pg_stat_statements.c File Reference

#include "postgres.h"
#include <math.h>
#include <sys/stat.h>
#include <unistd.h>
#include "access/htup_details.h"
#include "access/parallel.h"
#include "catalog/pg_authid.h"
#include "executor/instrument.h"
#include "funcapi.h"
#include "jit/jit.h"
#include "mb/pg_wchar.h"
#include "miscadmin.h"
#include "nodes/queryjumble.h"
#include "optimizer/planner.h"
#include "parser/analyze.h"
#include "pgstat.h"
#include "storage/fd.h"
#include "storage/ipc.h"
#include "storage/lwlock.h"
#include "storage/shmem.h"
#include "storage/spin.h"
#include "tcop/utility.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/memutils.h"
#include "utils/timestamp.h"
#include "utils/tuplestore.h"

Include dependency graph for pg_stat_statements.c:

Go to the source code of this file.

Data Structures
struct	pgssHashKey
struct	Counters
struct	pgssGlobalStats
struct	pgssEntry
struct	pgssSharedState

Macros
#define	PGSS_DUMP_FILE   PGSTAT_STAT_PERMANENT_DIRECTORY "/pg_stat_statements.stat"
#define	PGSS_TEXT_FILE   PG_STAT_TMP_DIR "/pgss_query_texts.stat"
#define	USAGE_EXEC(duration)   (1.0)
#define	USAGE_INIT   (1.0) /* including initial planning */
#define	ASSUMED_MEDIAN_INIT   (10.0) /* initial assumed median usage */
#define	ASSUMED_LENGTH_INIT   1024 /* initial assumed mean query length */
#define	USAGE_DECREASE_FACTOR   (0.99) /* decreased every entry_dealloc */
#define	STICKY_DECREASE_FACTOR   (0.50) /* factor for sticky entries */
#define	USAGE_DEALLOC_PERCENT   5 /* free this % of entries at once */
#define	IS_STICKY(c)   ((c.calls[PGSS_PLAN] + c.calls[PGSS_EXEC]) == 0)
#define	PGSS_NUMKIND   (PGSS_EXEC + 1)
#define	pgss_enabled(level)
#define	record_gc_qtexts()
#define	PG_STAT_STATEMENTS_COLS_V1_0   14
#define	PG_STAT_STATEMENTS_COLS_V1_1   18
#define	PG_STAT_STATEMENTS_COLS_V1_2   19
#define	PG_STAT_STATEMENTS_COLS_V1_3   23
#define	PG_STAT_STATEMENTS_COLS_V1_8   32
#define	PG_STAT_STATEMENTS_COLS_V1_9   33
#define	PG_STAT_STATEMENTS_COLS_V1_10   43
#define	PG_STAT_STATEMENTS_COLS_V1_11   49
#define	PG_STAT_STATEMENTS_COLS_V1_12   52
#define	PG_STAT_STATEMENTS_COLS_V1_13   54
#define	PG_STAT_STATEMENTS_COLS   54 /* maximum of above */
#define	PG_STAT_STATEMENTS_INFO_COLS   2
#define	SINGLE_ENTRY_RESET(e)

Typedefs
typedef enum pgssVersion	pgssVersion
typedef enum pgssStoreKind	pgssStoreKind
typedef struct pgssHashKey	pgssHashKey
typedef struct Counters	Counters
typedef struct pgssGlobalStats	pgssGlobalStats
typedef struct pgssEntry	pgssEntry
typedef struct pgssSharedState	pgssSharedState

Enumerations
enum	pgssVersion {   PGSS_V1_0 = 0 , PGSS_V1_1 , PGSS_V1_2 , PGSS_V1_3 ,   PGSS_V1_8 , PGSS_V1_9 , PGSS_V1_10 , PGSS_V1_11 ,   PGSS_V1_12 , PGSS_V1_13 }
enum	pgssStoreKind { PGSS_INVALID = -1 , PGSS_PLAN = 0 , PGSS_EXEC }
enum	PGSSTrackLevel { PGSS_TRACK_NONE , PGSS_TRACK_TOP , PGSS_TRACK_ALL }

Functions
	PG_MODULE_MAGIC_EXT (.name="pg_stat_statements",.version=PG_VERSION)
static void	pgss_shmem_request (void *arg)
static void	pgss_shmem_init (void *arg)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_reset)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_reset_1_7)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_reset_1_11)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_2)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_3)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_8)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_9)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_10)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_11)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_12)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_1_13)
	PG_FUNCTION_INFO_V1 (pg_stat_statements)
	PG_FUNCTION_INFO_V1 (pg_stat_statements_info)
static void	pgss_shmem_shutdown (int code, Datum arg)
static void	pgss_post_parse_analyze (ParseState *pstate, Query *query, const JumbleState *jstate)
static PlannedStmt *	pgss_planner (Query *parse, const char *query_string, int cursorOptions, ParamListInfo boundParams, ExplainState *es)
static void	pgss_ExecutorStart (QueryDesc *queryDesc, int eflags)
static void	pgss_ExecutorRun (QueryDesc *queryDesc, ScanDirection direction, uint64 count)
static void	pgss_ExecutorFinish (QueryDesc *queryDesc)
static void	pgss_ExecutorEnd (QueryDesc *queryDesc)
static void	pgss_ProcessUtility (PlannedStmt *pstmt, const char *queryString, bool readOnlyTree, ProcessUtilityContext context, ParamListInfo params, QueryEnvironment *queryEnv, DestReceiver *dest, QueryCompletion *qc)
static void	pgss_store (const char *query, int64 queryId, int query_location, int query_len, pgssStoreKind kind, double total_time, uint64 rows, const BufferUsage *bufusage, const WalUsage *walusage, const struct JitInstrumentation *jitusage, const JumbleState *jstate, int parallel_workers_to_launch, int parallel_workers_launched, PlannedStmtOrigin planOrigin)
static void	pg_stat_statements_internal (FunctionCallInfo fcinfo, pgssVersion api_version, bool showtext)
static pgssEntry *	entry_alloc (pgssHashKey *key, Size query_offset, int query_len, int encoding, bool sticky)
static void	entry_dealloc (void)
static bool	qtext_store (const char *query, int query_len, Size *query_offset, int *gc_count)
static char *	qtext_load_file (Size *buffer_size)
static char *	qtext_fetch (Size query_offset, int query_len, char *buffer, Size buffer_size)
static bool	need_gc_qtexts (void)
static void	gc_qtexts (void)
static TimestampTz	entry_reset (Oid userid, Oid dbid, int64 queryid, bool minmax_only)
static char *	generate_normalized_query (const JumbleState *jstate, const char *query, int query_loc, int *query_len_p)
void	_PG_init (void)
Datum	pg_stat_statements_reset_1_7 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_reset_1_11 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_reset (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_13 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_12 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_11 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_10 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_9 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_8 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_3 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_1_2 (PG_FUNCTION_ARGS)
Datum	pg_stat_statements (PG_FUNCTION_ARGS)
Datum	pg_stat_statements_info (PG_FUNCTION_ARGS)
static int	entry_cmp (const void *lhs, const void *rhs)

Variables
static const uint32	PGSS_FILE_HEADER = 0x20250731
static const uint32	PGSS_PG_MAJOR_VERSION = PG_VERSION_NUM / 100
static pgssSharedState *	pgss
static HTAB *	pgss_hash
static const ShmemCallbacks	pgss_shmem_callbacks
static int	nesting_level = 0
static post_parse_analyze_hook_type	prev_post_parse_analyze_hook = NULL
static planner_hook_type	prev_planner_hook = NULL
static ExecutorStart_hook_type	prev_ExecutorStart = NULL
static ExecutorRun_hook_type	prev_ExecutorRun = NULL
static ExecutorFinish_hook_type	prev_ExecutorFinish = NULL
static ExecutorEnd_hook_type	prev_ExecutorEnd = NULL
static ProcessUtility_hook_type	prev_ProcessUtility = NULL
static const struct config_enum_entry	track_options []
static int	pgss_max = 5000
static int	pgss_track = PGSS_TRACK_TOP
static bool	pgss_track_utility = true
static bool	pgss_track_planning = false
static bool	pgss_save = true

Macro Definition Documentation

ASSUMED_LENGTH_INIT

#define ASSUMED_LENGTH_INIT   1024 /* initial assumed mean query length */

Definition at line 97 of file pg_stat_statements.c.

ASSUMED_MEDIAN_INIT

#define ASSUMED_MEDIAN_INIT   (10.0) /* initial assumed median usage */

Definition at line 96 of file pg_stat_statements.c.

IS_STICKY

#define IS_STICKY

(

c

)

((c.calls[PGSS_PLAN] + c.calls[PGSS_EXEC]) == 0)

Definition at line 101 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS

#define PG_STAT_STATEMENTS_COLS   54 /* maximum of above */

Definition at line 1559 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_0

#define PG_STAT_STATEMENTS_COLS_V1_0   14

Definition at line 1549 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_1

#define PG_STAT_STATEMENTS_COLS_V1_1   18

Definition at line 1550 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_10

#define PG_STAT_STATEMENTS_COLS_V1_10   43

Definition at line 1555 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_11

#define PG_STAT_STATEMENTS_COLS_V1_11   49

Definition at line 1556 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_12

#define PG_STAT_STATEMENTS_COLS_V1_12   52

Definition at line 1557 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_13

#define PG_STAT_STATEMENTS_COLS_V1_13   54

Definition at line 1558 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_2

#define PG_STAT_STATEMENTS_COLS_V1_2   19

Definition at line 1551 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_3

#define PG_STAT_STATEMENTS_COLS_V1_3   23

Definition at line 1552 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_8

#define PG_STAT_STATEMENTS_COLS_V1_8   32

Definition at line 1553 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_COLS_V1_9

#define PG_STAT_STATEMENTS_COLS_V1_9   33

Definition at line 1554 of file pg_stat_statements.c.

PG_STAT_STATEMENTS_INFO_COLS

#define PG_STAT_STATEMENTS_INFO_COLS   2

Definition at line 2029 of file pg_stat_statements.c.

PGSS_DUMP_FILE

#define PGSS_DUMP_FILE   PGSTAT_STAT_PERMANENT_DIRECTORY "/pg_stat_statements.stat"

Definition at line 80 of file pg_stat_statements.c.

pgss_enabled

#define pgss_enabled

(

level

)

Value:

    (!IsParallelWorker() && \
    (pgss_track == PGSS_TRACK_ALL || \
    (pgss_track == PGSS_TRACK_TOP && (level) == 0)))

Definition at line 310 of file pg_stat_statements.c.

       { \
		SpinLockAcquire(&pgss->mutex); \
        pgss->gc_count++; \
		SpinLockRelease(&pgss->mutex); \
    } while(0)
 
/*---- Function declarations ----*/
 
PG_FUNCTION_INFO_V1(pg_stat_statements_reset);
PG_FUNCTION_INFO_V1(pg_stat_statements_reset_1_7);
PG_FUNCTION_INFO_V1(pg_stat_statements_reset_1_11);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_2);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_3);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_8);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_9);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_10);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_11);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_12);
PG_FUNCTION_INFO_V1(pg_stat_statements_1_13);
PG_FUNCTION_INFO_V1(pg_stat_statements);
PG_FUNCTION_INFO_V1(pg_stat_statements_info);
 
static void pgss_shmem_shutdown(int code, Datum arg);
static void pgss_post_parse_analyze(ParseState *pstate, Query *query,
                                    const JumbleState *jstate);
static PlannedStmt *pgss_planner(Query *parse,
                                 const char *query_string,
                                 int cursorOptions,
                                 ParamListInfo boundParams,
                                 ExplainState *es);
static void pgss_ExecutorStart(QueryDesc *queryDesc, int eflags);
static void pgss_ExecutorRun(QueryDesc *queryDesc,
                             ScanDirection direction,
                             uint64 count);
static void pgss_ExecutorFinish(QueryDesc *queryDesc);
static void pgss_ExecutorEnd(QueryDesc *queryDesc);
static void pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
                                bool readOnlyTree,
                                ProcessUtilityContext context, ParamListInfo params,
                                QueryEnvironment *queryEnv,
                                DestReceiver *dest, QueryCompletion *qc);
static void pgss_store(const char *query, int64 queryId,
                       int query_location, int query_len,
                       pgssStoreKind kind,
                       double total_time, uint64 rows,
                       const BufferUsage *bufusage,
                       const WalUsage *walusage,
                       const struct JitInstrumentation *jitusage,
                       const JumbleState *jstate,
                       int parallel_workers_to_launch,
                       int parallel_workers_launched,
                       PlannedStmtOrigin planOrigin);
static void pg_stat_statements_internal(FunctionCallInfo fcinfo,
                                        pgssVersion api_version,
                                        bool showtext);
static pgssEntry *entry_alloc(pgssHashKey *key, Size query_offset, int query_len,
                              int encoding, bool sticky);
static void entry_dealloc(void);
static bool qtext_store(const char *query, int query_len,
                        Size *query_offset, int *gc_count);
static char *qtext_load_file(Size *buffer_size);
static char *qtext_fetch(Size query_offset, int query_len,
                         char *buffer, Size buffer_size);
static bool need_gc_qtexts(void);
static void gc_qtexts(void);
static TimestampTz entry_reset(Oid userid, Oid dbid, int64 queryid, bool minmax_only);
static char *generate_normalized_query(const JumbleState *jstate,
                                       const char *query,
                                       int query_loc, int *query_len_p);
 
/*
 * Module load callback
 */
void
_PG_init(void)
{
    /*
     * In order to create our shared memory area, we have to be loaded via
     * shared_preload_libraries.  If not, fall out without hooking into any of
     * the main system.  (We don't throw error here because it seems useful to
     * allow the pg_stat_statements functions to be created even when the
     * module isn't active.  The functions must protect themselves against
     * being called then, however.)
     */
    if (!process_shared_preload_libraries_in_progress)
        return;
 
    /*
     * Inform the postmaster that we want to enable query_id calculation if
     * compute_query_id is set to auto.
     */
    EnableQueryId();
 
    /*
     * Define (or redefine) custom GUC variables.
     */
    DefineCustomIntVariable("pg_stat_statements.max",
                            "Sets the maximum number of statements tracked by pg_stat_statements.",
                            NULL,
                            &pgss_max,
                            5000,
                            100,
                            INT_MAX / 2,
                            PGC_POSTMASTER,
                            0,
                            NULL,
                            NULL,
                            NULL);
 
    DefineCustomEnumVariable("pg_stat_statements.track",
                             "Selects which statements are tracked by pg_stat_statements.",
                             NULL,
                             &pgss_track,
                             PGSS_TRACK_TOP,
                             track_options,
                             PGC_SUSET,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    DefineCustomBoolVariable("pg_stat_statements.track_utility",
                             "Selects whether utility commands are tracked by pg_stat_statements.",
                             NULL,
                             &pgss_track_utility,
                             true,
                             PGC_SUSET,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    DefineCustomBoolVariable("pg_stat_statements.track_planning",
                             "Selects whether planning duration is tracked by pg_stat_statements.",
                             NULL,
                             &pgss_track_planning,
                             false,
                             PGC_SUSET,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    DefineCustomBoolVariable("pg_stat_statements.save",
                             "Save pg_stat_statements statistics across server shutdowns.",
                             NULL,
                             &pgss_save,
                             true,
                             PGC_SIGHUP,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    MarkGUCPrefixReserved("pg_stat_statements");
 
    /*
     * Register our shared memory needs.
     */
    RegisterShmemCallbacks(&pgss_shmem_callbacks);
 
    /*
     * Install hooks.
     */
    prev_post_parse_analyze_hook = post_parse_analyze_hook;
    post_parse_analyze_hook = pgss_post_parse_analyze;
    prev_planner_hook = planner_hook;
    planner_hook = pgss_planner;
    prev_ExecutorStart = ExecutorStart_hook;
    ExecutorStart_hook = pgss_ExecutorStart;
    prev_ExecutorRun = ExecutorRun_hook;
    ExecutorRun_hook = pgss_ExecutorRun;
    prev_ExecutorFinish = ExecutorFinish_hook;
    ExecutorFinish_hook = pgss_ExecutorFinish;
    prev_ExecutorEnd = ExecutorEnd_hook;
    ExecutorEnd_hook = pgss_ExecutorEnd;
    prev_ProcessUtility = ProcessUtility_hook;
    ProcessUtility_hook = pgss_ProcessUtility;
}
 
/*
 * shmem request callback: Request shared memory resources.
 *
 * This is called at postmaster startup.  Note that the shared memory isn't
 * allocated here yet, this merely register our needs.
 *
 * In EXEC_BACKEND mode, this is also called in each backend, to re-attach to
 * the shared memory area that was already initialized.
 */
static void
pgss_shmem_request(void *arg)
{
    ShmemRequestHash(.name = "pg_stat_statements hash",
                     .nelems = pgss_max,
                     .hash_info.keysize = sizeof(pgssHashKey),
                     .hash_info.entrysize = sizeof(pgssEntry),
                     .hash_flags = HASH_ELEM | HASH_BLOBS,
                     .ptr = &pgss_hash,
        );
    ShmemRequestStruct(.name = "pg_stat_statements",
                       .size = sizeof(pgssSharedState),
                       .ptr = (void **) &pgss,
        );
}
 
/*
 * shmem init callback: Initialize our shared memory data structures at
 * postmaster startup.
 *
 * Load any pre-existing statistics from file.  Also create and load the
 * query-texts file, which is expected to exist (even if empty) while the
 * module is enabled.
 */
static void
pgss_shmem_init(void *arg)
{
    int         tranche_id;
    FILE       *file = NULL;
    FILE       *qfile = NULL;
    uint32      header;
    int32       num;
    int32       pgver;
    int32       i;
    int         buffer_size;
    char       *buffer = NULL;
 
    /*
     * We already checked that we're loaded from shared_preload_libraries in
     * _PG_init(), so we should not get here after postmaster startup.
     */
    Assert(!IsUnderPostmaster);
 
    /*
     * Initialize the shmem area with no statistics.
     */
    tranche_id = LWLockNewTrancheId("pg_stat_statements");
    LWLockInitialize(&pgss->lock.lock, tranche_id);
    pgss->cur_median_usage = ASSUMED_MEDIAN_INIT;
    pgss->mean_query_len = ASSUMED_LENGTH_INIT;
    SpinLockInit(&pgss->mutex);
    pgss->extent = 0;
    pgss->n_writers = 0;
    pgss->gc_count = 0;
    pgss->stats.dealloc = 0;
    pgss->stats.stats_reset = GetCurrentTimestamp();
 
    /* The hash table must've also been initialized by now */
    Assert(pgss_hash != NULL);
 
    /*
     * Set up a shmem exit hook to dump the statistics to disk on postmaster
     * (or standalone backend) exit.
     */
    on_shmem_exit(pgss_shmem_shutdown, (Datum) 0);
 
    /*
     * Load any pre-existing statistics from file.
     *
     * Note: we don't bother with locks here, because there should be no other
     * processes running when this code is reached.
     */
 
    /* Unlink query text file possibly left over from crash */
    unlink(PGSS_TEXT_FILE);
 
    /* Allocate new query text temp file */
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
        goto write_error;
 
    /*
     * If we were told not to load old statistics, we're done.  (Note we do
     * not try to unlink any old dump file in this case.  This seems a bit
     * questionable but it's the historical behavior.)
     */
    if (!pgss_save)
    {
        FreeFile(qfile);
        return;
    }
 
    /*
     * Attempt to load old statistics from the dump file.
     */
    file = AllocateFile(PGSS_DUMP_FILE, PG_BINARY_R);
    if (file == NULL)
    {
        if (errno != ENOENT)
            goto read_error;
        /* No existing persisted stats file, so we're done */
        FreeFile(qfile);
        return;
    }
 
    buffer_size = 2048;
    buffer = (char *) palloc(buffer_size);
 
    if (fread(&header, sizeof(uint32), 1, file) != 1 ||
        fread(&pgver, sizeof(uint32), 1, file) != 1 ||
        fread(&num, sizeof(int32), 1, file) != 1)
        goto read_error;
 
    if (header != PGSS_FILE_HEADER ||
        pgver != PGSS_PG_MAJOR_VERSION)
        goto data_error;
 
    for (i = 0; i < num; i++)
    {
        pgssEntry   temp;
        pgssEntry  *entry;
        Size        query_offset;
 
        if (fread(&temp, sizeof(pgssEntry), 1, file) != 1)
            goto read_error;
 
        /* Encoding is the only field we can easily sanity-check */
        if (!PG_VALID_BE_ENCODING(temp.encoding))
            goto data_error;
 
        /* Resize buffer as needed */
        if (temp.query_len >= buffer_size)
        {
            buffer_size = Max(buffer_size * 2, temp.query_len + 1);
            buffer = repalloc(buffer, buffer_size);
        }
 
        if (fread(buffer, 1, temp.query_len + 1, file) != temp.query_len + 1)
            goto read_error;
 
        /* Should have a trailing null, but let's make sure */
        buffer[temp.query_len] = '\0';
 
        /* Skip loading "sticky" entries */
        if (IS_STICKY(temp.counters))
            continue;
 
        /* Store the query text */
        query_offset = pgss->extent;
        if (fwrite(buffer, 1, temp.query_len + 1, qfile) != temp.query_len + 1)
            goto write_error;
        pgss->extent += temp.query_len + 1;
 
        /* make the hashtable entry (discards old entries if too many) */
        entry = entry_alloc(&temp.key, query_offset, temp.query_len,
                            temp.encoding,
                            false);
 
        /* copy in the actual stats */
        entry->counters = temp.counters;
        entry->stats_since = temp.stats_since;
        entry->minmax_stats_since = temp.minmax_stats_since;
    }
 
    /* Read global statistics for pg_stat_statements */
    if (fread(&pgss->stats, sizeof(pgssGlobalStats), 1, file) != 1)
        goto read_error;
 
    pfree(buffer);
    FreeFile(file);
    FreeFile(qfile);
 
    /*
     * Remove the persisted stats file so it's not included in
     * backups/replication standbys, etc.  A new file will be written on next
     * shutdown.
     *
     * Note: it's okay if the PGSS_TEXT_FILE is included in a basebackup,
     * because we remove that file on startup; it acts inversely to
     * PGSS_DUMP_FILE, in that it is only supposed to be around when the
     * server is running, whereas PGSS_DUMP_FILE is only supposed to be around
     * when the server is not running.  Leaving the file creates no danger of
     * a newly restored database having a spurious record of execution costs,
     * which is what we're really concerned about here.
     */
    unlink(PGSS_DUMP_FILE);
 
    return;
 
read_error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not read file \"%s\": %m",
                    PGSS_DUMP_FILE)));
    goto fail;
data_error:
    ereport(LOG,
            (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
             errmsg("ignoring invalid data in file \"%s\"",
                    PGSS_DUMP_FILE)));
    goto fail;
write_error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not write file \"%s\": %m",
                    PGSS_TEXT_FILE)));
fail:
    if (buffer)
        pfree(buffer);
    if (file)
        FreeFile(file);
    if (qfile)
        FreeFile(qfile);
    /* If possible, throw away the bogus file; ignore any error */
    unlink(PGSS_DUMP_FILE);
 
    /*
     * Don't unlink PGSS_TEXT_FILE here; it should always be around while the
     * server is running with pg_stat_statements enabled
     */
}
 
/*
 * shmem_shutdown hook: Dump statistics into file.
 *
 * Note: we don't bother with acquiring lock, because there should be no
 * other processes running when this is called.
 */
static void
pgss_shmem_shutdown(int code, Datum arg)
{
    FILE       *file;
    char       *qbuffer = NULL;
    Size        qbuffer_size = 0;
    HASH_SEQ_STATUS hash_seq;
    int32       num_entries;
    pgssEntry  *entry;
 
    /* Don't try to dump during a crash. */
    if (code)
        return;
 
    /* Safety check ... shouldn't get here unless shmem is set up. */
    if (!pgss || !pgss_hash)
        return;
 
    /* Don't dump if told not to. */
    if (!pgss_save)
        return;
 
    file = AllocateFile(PGSS_DUMP_FILE ".tmp", PG_BINARY_W);
    if (file == NULL)
        goto error;
 
    if (fwrite(&PGSS_FILE_HEADER, sizeof(uint32), 1, file) != 1)
        goto error;
    if (fwrite(&PGSS_PG_MAJOR_VERSION, sizeof(uint32), 1, file) != 1)
        goto error;
    num_entries = hash_get_num_entries(pgss_hash);
    if (fwrite(&num_entries, sizeof(int32), 1, file) != 1)
        goto error;
 
    qbuffer = qtext_load_file(&qbuffer_size);
    if (qbuffer == NULL)
        goto error;
 
    /*
     * When serializing to disk, we store query texts immediately after their
     * entry data.  Any orphaned query texts are thereby excluded.
     */
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        int         len = entry->query_len;
        char       *qstr = qtext_fetch(entry->query_offset, len,
                                       qbuffer, qbuffer_size);
 
        if (qstr == NULL)
            continue;           /* Ignore any entries with bogus texts */
 
        if (fwrite(entry, sizeof(pgssEntry), 1, file) != 1 ||
            fwrite(qstr, 1, len + 1, file) != len + 1)
        {
            /* note: we assume hash_seq_term won't change errno */
            hash_seq_term(&hash_seq);
            goto error;
        }
    }
 
    /* Dump global statistics for pg_stat_statements */
    if (fwrite(&pgss->stats, sizeof(pgssGlobalStats), 1, file) != 1)
        goto error;
 
    pfree(qbuffer);
    qbuffer = NULL;
 
    if (FreeFile(file))
    {
        file = NULL;
        goto error;
    }
 
    /*
     * Rename file into place, so we atomically replace any old one.
     */
    (void) durable_rename(PGSS_DUMP_FILE ".tmp", PGSS_DUMP_FILE, LOG);
 
    /* Unlink query-texts file; it's not needed while shutdown */
    unlink(PGSS_TEXT_FILE);
 
    return;
 
error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not write file \"%s\": %m",
                    PGSS_DUMP_FILE ".tmp")));
    if (qbuffer)
        pfree(qbuffer);
    if (file)
        FreeFile(file);
    unlink(PGSS_DUMP_FILE ".tmp");
    unlink(PGSS_TEXT_FILE);
}
 
/*
 * Post-parse-analysis hook: mark query with a queryId
 */
static void
pgss_post_parse_analyze(ParseState *pstate, Query *query, const JumbleState *jstate)
{
    if (prev_post_parse_analyze_hook)
        prev_post_parse_analyze_hook(pstate, query, jstate);
 
    /* Safety check... */
    if (!pgss || !pgss_hash || !pgss_enabled(nesting_level))
        return;
 
    /*
     * If it's EXECUTE, clear the queryId so that stats will accumulate for
     * the underlying PREPARE.  But don't do this if we're not tracking
     * utility statements, to avoid messing up another extension that might be
     * tracking them.
     */
    if (query->utilityStmt)
    {
        if (pgss_track_utility && IsA(query->utilityStmt, ExecuteStmt))
        {
            query->queryId = INT64CONST(0);
            return;
        }
    }
 
    /*
     * If query jumbling were able to identify any ignorable constants, we
     * immediately create a hash table entry for the query, so that we can
     * record the normalized form of the query string.  If there were no such
     * constants, the normalized string would be the same as the query text
     * anyway, so there's no need for an early entry.
     */
    if (jstate && jstate->clocations_count > 0)
        pgss_store(pstate->p_sourcetext,
                   query->queryId,
                   query->stmt_location,
                   query->stmt_len,
                   PGSS_INVALID,
                   0,
                   0,
                   NULL,
                   NULL,
                   NULL,
                   jstate,
                   0,
                   0,
                   PLAN_STMT_UNKNOWN);
}
 
/*
 * Planner hook: forward to regular planner, but measure planning time
 * if needed.
 */
static PlannedStmt *
pgss_planner(Query *parse,
             const char *query_string,
             int cursorOptions,
             ParamListInfo boundParams,
             ExplainState *es)
{
    PlannedStmt *result;
 
    /*
     * We can't process the query if no query_string is provided, as
     * pgss_store needs it.  We also ignore query without queryid, as it would
     * be treated as a utility statement, which may not be the case.
     */
    if (pgss_enabled(nesting_level)
        && pgss_track_planning && query_string
        && parse->queryId != INT64CONST(0))
    {
        instr_time  start;
        instr_time  duration;
        BufferUsage bufusage_start,
                    bufusage;
        WalUsage    walusage_start,
                    walusage;
 
        /* We need to track buffer usage as the planner can access them. */
        bufusage_start = pgBufferUsage;
 
        /*
         * Similarly the planner could write some WAL records in some cases
         * (e.g. setting a hint bit with those being WAL-logged)
         */
        walusage_start = pgWalUsage;
        INSTR_TIME_SET_CURRENT(start);
 
        nesting_level++;
        PG_TRY();
        {
            if (prev_planner_hook)
                result = prev_planner_hook(parse, query_string, cursorOptions,
                                           boundParams, es);
            else
                result = standard_planner(parse, query_string, cursorOptions,
                                          boundParams, es);
        }
        PG_FINALLY();
        {
            nesting_level--;
        }
        PG_END_TRY();
 
        INSTR_TIME_SET_CURRENT(duration);
        INSTR_TIME_SUBTRACT(duration, start);
 
        /* calc differences of buffer counters. */
        memset(&bufusage, 0, sizeof(BufferUsage));
        BufferUsageAccumDiff(&bufusage, &pgBufferUsage, &bufusage_start);
 
        /* calc differences of WAL counters. */
        memset(&walusage, 0, sizeof(WalUsage));
        WalUsageAccumDiff(&walusage, &pgWalUsage, &walusage_start);
 
        pgss_store(query_string,
                   parse->queryId,
                   parse->stmt_location,
                   parse->stmt_len,
                   PGSS_PLAN,
                   INSTR_TIME_GET_MILLISEC(duration),
                   0,
                   &bufusage,
                   &walusage,
                   NULL,
                   NULL,
                   0,
                   0,
                   result->planOrigin);
    }
    else
    {
        /*
         * Even though we're not tracking plan time for this statement, we
         * must still increment the nesting level, to ensure that functions
         * evaluated during planning are not seen as top-level calls.
         */
        nesting_level++;
        PG_TRY();
        {
            if (prev_planner_hook)
                result = prev_planner_hook(parse, query_string, cursorOptions,
                                           boundParams, es);
            else
                result = standard_planner(parse, query_string, cursorOptions,
                                          boundParams, es);
        }
        PG_FINALLY();
        {
            nesting_level--;
        }
        PG_END_TRY();
    }
 
    return result;
}
 
/*
 * ExecutorStart hook: start up tracking if needed
 */
static void
pgss_ExecutorStart(QueryDesc *queryDesc, int eflags)
{
    /*
     * If query has queryId zero, don't track it.  This prevents double
     * counting of optimizable statements that are directly contained in
     * utility statements.
     */
    if (pgss_enabled(nesting_level) && queryDesc->plannedstmt->queryId != INT64CONST(0))
    {
        /* Request all summary instrumentation, i.e. timing, buffers and WAL */
        queryDesc->query_instr_options |= INSTRUMENT_ALL;
    }
 
    if (prev_ExecutorStart)
        prev_ExecutorStart(queryDesc, eflags);
    else
        standard_ExecutorStart(queryDesc, eflags);
}
 
/*
 * ExecutorRun hook: all we need do is track nesting depth
 */
static void
pgss_ExecutorRun(QueryDesc *queryDesc, ScanDirection direction, uint64 count)
{
    nesting_level++;
    PG_TRY();
    {
        if (prev_ExecutorRun)
            prev_ExecutorRun(queryDesc, direction, count);
        else
            standard_ExecutorRun(queryDesc, direction, count);
    }
    PG_FINALLY();
    {
        nesting_level--;
    }
    PG_END_TRY();
}
 
/*
 * ExecutorFinish hook: all we need do is track nesting depth
 */
static void
pgss_ExecutorFinish(QueryDesc *queryDesc)
{
    nesting_level++;
    PG_TRY();
    {
        if (prev_ExecutorFinish)
            prev_ExecutorFinish(queryDesc);
        else
            standard_ExecutorFinish(queryDesc);
    }
    PG_FINALLY();
    {
        nesting_level--;
    }
    PG_END_TRY();
}
 
/*
 * ExecutorEnd hook: store results if needed
 */
static void
pgss_ExecutorEnd(QueryDesc *queryDesc)
{
    int64       queryId = queryDesc->plannedstmt->queryId;
 
    if (queryId != INT64CONST(0) && queryDesc->query_instr &&
        pgss_enabled(nesting_level))
    {
        pgss_store(queryDesc->sourceText,
                   queryId,
                   queryDesc->plannedstmt->stmt_location,
                   queryDesc->plannedstmt->stmt_len,
                   PGSS_EXEC,
                   INSTR_TIME_GET_MILLISEC(queryDesc->query_instr->total),
                   queryDesc->estate->es_total_processed,
                   &queryDesc->query_instr->bufusage,
                   &queryDesc->query_instr->walusage,
                   queryDesc->estate->es_jit ? &queryDesc->estate->es_jit->instr : NULL,
                   NULL,
                   queryDesc->estate->es_parallel_workers_to_launch,
                   queryDesc->estate->es_parallel_workers_launched,
                   queryDesc->plannedstmt->planOrigin);
    }
 
    if (prev_ExecutorEnd)
        prev_ExecutorEnd(queryDesc);
    else
        standard_ExecutorEnd(queryDesc);
}
 
/*
 * ProcessUtility hook
 */
static void
pgss_ProcessUtility(PlannedStmt *pstmt, const char *queryString,
                    bool readOnlyTree,
                    ProcessUtilityContext context,
                    ParamListInfo params, QueryEnvironment *queryEnv,
                    DestReceiver *dest, QueryCompletion *qc)
{
    Node       *parsetree = pstmt->utilityStmt;
    int64       saved_queryId = pstmt->queryId;
    int         saved_stmt_location = pstmt->stmt_location;
    int         saved_stmt_len = pstmt->stmt_len;
    bool        enabled = pgss_track_utility && pgss_enabled(nesting_level);
 
    /*
     * Force utility statements to get queryId zero.  We do this even in cases
     * where the statement contains an optimizable statement for which a
     * queryId could be derived (such as EXPLAIN or DECLARE CURSOR).  For such
     * cases, runtime control will first go through ProcessUtility and then
     * the executor, and we don't want the executor hooks to do anything,
     * since we are already measuring the statement's costs at the utility
     * level.
     *
     * Note that this is only done if pg_stat_statements is enabled and
     * configured to track utility statements, in the unlikely possibility
     * that user configured another extension to handle utility statements
     * only.
     */
    if (enabled)
        pstmt->queryId = INT64CONST(0);
 
    /*
     * If it's an EXECUTE statement, we don't track it and don't increment the
     * nesting level.  This allows the cycles to be charged to the underlying
     * PREPARE instead (by the Executor hooks), which is much more useful.
     *
     * We also don't track execution of PREPARE.  If we did, we would get one
     * hash table entry for the PREPARE (with hash calculated from the query
     * string), and then a different one with the same query string (but hash
     * calculated from the query tree) would be used to accumulate costs of
     * ensuing EXECUTEs.  This would be confusing.  Since PREPARE doesn't
     * actually run the planner (only parse+rewrite), its costs are generally
     * pretty negligible and it seems okay to just ignore it.
     */
    if (enabled &&
        !IsA(parsetree, ExecuteStmt) &&
        !IsA(parsetree, PrepareStmt))
    {
        instr_time  start;
        instr_time  duration;
        uint64      rows;
        BufferUsage bufusage_start,
                    bufusage;
        WalUsage    walusage_start,
                    walusage;
 
        bufusage_start = pgBufferUsage;
        walusage_start = pgWalUsage;
        INSTR_TIME_SET_CURRENT(start);
 
        nesting_level++;
        PG_TRY();
        {
            if (prev_ProcessUtility)
                prev_ProcessUtility(pstmt, queryString, readOnlyTree,
                                    context, params, queryEnv,
                                    dest, qc);
            else
                standard_ProcessUtility(pstmt, queryString, readOnlyTree,
                                        context, params, queryEnv,
                                        dest, qc);
        }
        PG_FINALLY();
        {
            nesting_level--;
        }
        PG_END_TRY();
 
        /*
         * CAUTION: do not access the *pstmt data structure again below here.
         * If it was a ROLLBACK or similar, that data structure may have been
         * freed.  We must copy everything we still need into local variables,
         * which we did above.
         *
         * For the same reason, we can't risk restoring pstmt->queryId to its
         * former value, which'd otherwise be a good idea.
         */
 
        INSTR_TIME_SET_CURRENT(duration);
        INSTR_TIME_SUBTRACT(duration, start);
 
        /*
         * Track the total number of rows retrieved or affected by the utility
         * statements of COPY, FETCH, CREATE TABLE AS, CREATE MATERIALIZED
         * VIEW, REFRESH MATERIALIZED VIEW and SELECT INTO.
         */
        rows = (qc && (qc->commandTag == CMDTAG_COPY ||
                       qc->commandTag == CMDTAG_FETCH ||
                       qc->commandTag == CMDTAG_SELECT ||
                       qc->commandTag == CMDTAG_REFRESH_MATERIALIZED_VIEW)) ?
            qc->nprocessed : 0;
 
        /* calc differences of buffer counters. */
        memset(&bufusage, 0, sizeof(BufferUsage));
        BufferUsageAccumDiff(&bufusage, &pgBufferUsage, &bufusage_start);
 
        /* calc differences of WAL counters. */
        memset(&walusage, 0, sizeof(WalUsage));
        WalUsageAccumDiff(&walusage, &pgWalUsage, &walusage_start);
 
        pgss_store(queryString,
                   saved_queryId,
                   saved_stmt_location,
                   saved_stmt_len,
                   PGSS_EXEC,
                   INSTR_TIME_GET_MILLISEC(duration),
                   rows,
                   &bufusage,
                   &walusage,
                   NULL,
                   NULL,
                   0,
                   0,
                   pstmt->planOrigin);
    }
    else
    {
        /*
         * Even though we're not tracking execution time for this statement,
         * we must still increment the nesting level, to ensure that functions
         * evaluated within it are not seen as top-level calls.  But don't do
         * so for EXECUTE; that way, when control reaches pgss_planner or
         * pgss_ExecutorStart, we will treat the costs as top-level if
         * appropriate.  Likewise, don't bump for PREPARE, so that parse
         * analysis will treat the statement as top-level if appropriate.
         *
         * To be absolutely certain we don't mess up the nesting level,
         * evaluate the bump_level condition just once.
         */
        bool        bump_level =
            !IsA(parsetree, ExecuteStmt) &&
            !IsA(parsetree, PrepareStmt);
 
        if (bump_level)
            nesting_level++;
        PG_TRY();
        {
            if (prev_ProcessUtility)
                prev_ProcessUtility(pstmt, queryString, readOnlyTree,
                                    context, params, queryEnv,
                                    dest, qc);
            else
                standard_ProcessUtility(pstmt, queryString, readOnlyTree,
                                        context, params, queryEnv,
                                        dest, qc);
        }
        PG_FINALLY();
        {
            if (bump_level)
                nesting_level--;
        }
        PG_END_TRY();
    }
}
 
/*
 * Store some statistics for a statement.
 *
 * If jstate is not NULL then we're trying to create an entry for which
 * we have no statistics as yet; we just want to record the normalized
 * query string.  total_time, rows, bufusage and walusage are ignored in this
 * case.
 *
 * If kind is PGSS_PLAN or PGSS_EXEC, its value is used as the array position
 * for the arrays in the Counters field.
 */
static void
pgss_store(const char *query, int64 queryId,
           int query_location, int query_len,
           pgssStoreKind kind,
           double total_time, uint64 rows,
           const BufferUsage *bufusage,
           const WalUsage *walusage,
           const struct JitInstrumentation *jitusage,
           const JumbleState *jstate,
           int parallel_workers_to_launch,
           int parallel_workers_launched,
           PlannedStmtOrigin planOrigin)
{
    pgssHashKey key;
    pgssEntry  *entry;
    char       *norm_query = NULL;
    int         encoding = GetDatabaseEncoding();
 
    Assert(query != NULL);
 
    /* Safety check... */
    if (!pgss || !pgss_hash)
        return;
 
    /*
     * Nothing to do if compute_query_id isn't enabled and no other module
     * computed a query identifier.
     */
    if (queryId == INT64CONST(0))
        return;
 
    /*
     * Confine our attention to the relevant part of the string, if the query
     * is a portion of a multi-statement source string, and update query
     * location and length if needed.
     */
    query = CleanQuerytext(query, &query_location, &query_len);
 
    /* Set up key for hashtable search */
 
    /* clear padding */
    memset(&key, 0, sizeof(pgssHashKey));
 
    key.userid = GetUserId();
    key.dbid = MyDatabaseId;
    key.queryid = queryId;
    key.toplevel = (nesting_level == 0);
 
    /* Lookup the hash table entry with shared lock. */
    LWLockAcquire(&pgss->lock.lock, LW_SHARED);
 
    entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
 
    /* Create new entry, if not present */
    if (!entry)
    {
        Size        query_offset;
        int         gc_count;
        bool        stored;
        bool        do_gc;
 
        /*
         * Create a new, normalized query string if caller asked.  We don't
         * need to hold the lock while doing this work.  (Note: in any case,
         * it's possible that someone else creates a duplicate hashtable entry
         * in the interval where we don't hold the lock below.  That case is
         * handled by entry_alloc.)
         */
        if (jstate)
        {
            LWLockRelease(&pgss->lock.lock);
            norm_query = generate_normalized_query(jstate, query,
                                                   query_location,
                                                   &query_len);
            LWLockAcquire(&pgss->lock.lock, LW_SHARED);
        }
 
        /* Append new query text to file with only shared lock held */
        stored = qtext_store(norm_query ? norm_query : query, query_len,
                             &query_offset, &gc_count);
 
        /*
         * Determine whether we need to garbage collect external query texts
         * while the shared lock is still held.  This micro-optimization
         * avoids taking the time to decide this while holding exclusive lock.
         */
        do_gc = need_gc_qtexts();
 
        /* Need exclusive lock to make a new hashtable entry - promote */
        LWLockRelease(&pgss->lock.lock);
        LWLockAcquire(&pgss->lock.lock, LW_EXCLUSIVE);
 
        /*
         * A garbage collection may have occurred while we weren't holding the
         * lock.  In the unlikely event that this happens, the query text we
         * stored above will have been garbage collected, so write it again.
         * This should be infrequent enough that doing it while holding
         * exclusive lock isn't a performance problem.
         */
        if (!stored || pgss->gc_count != gc_count)
            stored = qtext_store(norm_query ? norm_query : query, query_len,
                                 &query_offset, NULL);
 
        /* If we failed to write to the text file, give up */
        if (!stored)
            goto done;
 
        /* OK to create a new hashtable entry */
        entry = entry_alloc(&key, query_offset, query_len, encoding,
                            jstate != NULL);
 
        /* If needed, perform garbage collection while exclusive lock held */
        if (do_gc)
            gc_qtexts();
    }
 
    /* Increment the counts, except when jstate is not NULL */
    if (!jstate)
    {
        Assert(kind == PGSS_PLAN || kind == PGSS_EXEC);
 
        /*
         * Grab the spinlock while updating the counters (see comment about
         * locking rules at the head of the file)
         */
        SpinLockAcquire(&entry->mutex);
 
        /* "Unstick" entry if it was previously sticky */
        if (IS_STICKY(entry->counters))
            entry->counters.usage = USAGE_INIT;
 
        entry->counters.calls[kind] += 1;
        entry->counters.total_time[kind] += total_time;
 
        if (entry->counters.calls[kind] == 1)
        {
            entry->counters.min_time[kind] = total_time;
            entry->counters.max_time[kind] = total_time;
            entry->counters.mean_time[kind] = total_time;
        }
        else
        {
            /*
             * Welford's method for accurately computing variance. See
             * <http://www.johndcook.com/blog/standard_deviation/>
             */
            double      old_mean = entry->counters.mean_time[kind];
 
            entry->counters.mean_time[kind] +=
                (total_time - old_mean) / entry->counters.calls[kind];
            entry->counters.sum_var_time[kind] +=
                (total_time - old_mean) * (total_time - entry->counters.mean_time[kind]);
 
            /*
             * Calculate min and max time. min = 0 and max = 0 means that the
             * min/max statistics were reset
             */
            if (entry->counters.min_time[kind] == 0
                && entry->counters.max_time[kind] == 0)
            {
                entry->counters.min_time[kind] = total_time;
                entry->counters.max_time[kind] = total_time;
            }
            else
            {
                if (entry->counters.min_time[kind] > total_time)
                    entry->counters.min_time[kind] = total_time;
                if (entry->counters.max_time[kind] < total_time)
                    entry->counters.max_time[kind] = total_time;
            }
        }
        entry->counters.rows += rows;
        entry->counters.shared_blks_hit += bufusage->shared_blks_hit;
        entry->counters.shared_blks_read += bufusage->shared_blks_read;
        entry->counters.shared_blks_dirtied += bufusage->shared_blks_dirtied;
        entry->counters.shared_blks_written += bufusage->shared_blks_written;
        entry->counters.local_blks_hit += bufusage->local_blks_hit;
        entry->counters.local_blks_read += bufusage->local_blks_read;
        entry->counters.local_blks_dirtied += bufusage->local_blks_dirtied;
        entry->counters.local_blks_written += bufusage->local_blks_written;
        entry->counters.temp_blks_read += bufusage->temp_blks_read;
        entry->counters.temp_blks_written += bufusage->temp_blks_written;
        entry->counters.shared_blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->shared_blk_read_time);
        entry->counters.shared_blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->shared_blk_write_time);
        entry->counters.local_blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->local_blk_read_time);
        entry->counters.local_blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->local_blk_write_time);
        entry->counters.temp_blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->temp_blk_read_time);
        entry->counters.temp_blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->temp_blk_write_time);
        entry->counters.usage += USAGE_EXEC(total_time);
        entry->counters.wal_records += walusage->wal_records;
        entry->counters.wal_fpi += walusage->wal_fpi;
        entry->counters.wal_bytes += walusage->wal_bytes;
        entry->counters.wal_buffers_full += walusage->wal_buffers_full;
        if (jitusage)
        {
            entry->counters.jit_functions += jitusage->created_functions;
            entry->counters.jit_generation_time += INSTR_TIME_GET_MILLISEC(jitusage->generation_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->deform_counter))
                entry->counters.jit_deform_count++;
            entry->counters.jit_deform_time += INSTR_TIME_GET_MILLISEC(jitusage->deform_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->inlining_counter))
                entry->counters.jit_inlining_count++;
            entry->counters.jit_inlining_time += INSTR_TIME_GET_MILLISEC(jitusage->inlining_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->optimization_counter))
                entry->counters.jit_optimization_count++;
            entry->counters.jit_optimization_time += INSTR_TIME_GET_MILLISEC(jitusage->optimization_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->emission_counter))
                entry->counters.jit_emission_count++;
            entry->counters.jit_emission_time += INSTR_TIME_GET_MILLISEC(jitusage->emission_counter);
        }
 
        /* parallel worker counters */
        entry->counters.parallel_workers_to_launch += parallel_workers_to_launch;
        entry->counters.parallel_workers_launched += parallel_workers_launched;
 
        /* plan cache counters */
        if (planOrigin == PLAN_STMT_CACHE_GENERIC)
            entry->counters.generic_plan_calls++;
        else if (planOrigin == PLAN_STMT_CACHE_CUSTOM)
            entry->counters.custom_plan_calls++;
 
        SpinLockRelease(&entry->mutex);
    }
 
done:
    LWLockRelease(&pgss->lock.lock);
 
    /* We postpone this clean-up until we're out of the lock */
    if (norm_query)
        pfree(norm_query);
}
 
/*
 * Reset statement statistics corresponding to userid, dbid, and queryid.
 */
Datum
pg_stat_statements_reset_1_7(PG_FUNCTION_ARGS)
{
    Oid         userid;
    Oid         dbid;
    int64       queryid;
 
    userid = PG_GETARG_OID(0);
    dbid = PG_GETARG_OID(1);
    queryid = PG_GETARG_INT64(2);
 
    entry_reset(userid, dbid, queryid, false);
 
    PG_RETURN_VOID();
}
 
Datum
pg_stat_statements_reset_1_11(PG_FUNCTION_ARGS)
{
    Oid         userid;
    Oid         dbid;
    int64       queryid;
    bool        minmax_only;
 
    userid = PG_GETARG_OID(0);
    dbid = PG_GETARG_OID(1);
    queryid = PG_GETARG_INT64(2);
    minmax_only = PG_GETARG_BOOL(3);
 
    PG_RETURN_TIMESTAMPTZ(entry_reset(userid, dbid, queryid, minmax_only));
}
 
/*
 * Reset statement statistics.
 */
Datum
pg_stat_statements_reset(PG_FUNCTION_ARGS)
{
    entry_reset(0, 0, 0, false);
 
    PG_RETURN_VOID();
}
 
/* Number of output arguments (columns) for various API versions */
#define PG_STAT_STATEMENTS_COLS_V1_0    14
#define PG_STAT_STATEMENTS_COLS_V1_1    18
#define PG_STAT_STATEMENTS_COLS_V1_2    19
#define PG_STAT_STATEMENTS_COLS_V1_3    23
#define PG_STAT_STATEMENTS_COLS_V1_8    32
#define PG_STAT_STATEMENTS_COLS_V1_9    33
#define PG_STAT_STATEMENTS_COLS_V1_10   43
#define PG_STAT_STATEMENTS_COLS_V1_11   49
#define PG_STAT_STATEMENTS_COLS_V1_12   52
#define PG_STAT_STATEMENTS_COLS_V1_13   54
#define PG_STAT_STATEMENTS_COLS         54  /* maximum of above */
 
/*
 * Retrieve statement statistics.
 *
 * The SQL API of this function has changed multiple times, and will likely
 * do so again in future.  To support the case where a newer version of this
 * loadable module is being used with an old SQL declaration of the function,
 * we continue to support the older API versions.  For 1.2 and later, the
 * expected API version is identified by embedding it in the C name of the
 * function.  Unfortunately we weren't bright enough to do that for 1.1.
 */
Datum
pg_stat_statements_1_13(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_13, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_12(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_12, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_11(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_11, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_10(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_10, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_9(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_9, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_8(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_8, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_3(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_3, showtext);
 
    return (Datum) 0;
}
 
Datum
pg_stat_statements_1_2(PG_FUNCTION_ARGS)
{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_2, showtext);
 
    return (Datum) 0;
}
 
/*
 * Legacy entry point for pg_stat_statements() API versions 1.0 and 1.1.
 * This can be removed someday, perhaps.
 */
Datum
pg_stat_statements(PG_FUNCTION_ARGS)
{
    /* If it's really API 1.1, we'll figure that out below */
    pg_stat_statements_internal(fcinfo, PGSS_V1_0, true);
 
    return (Datum) 0;
}
 
/* Common code for all versions of pg_stat_statements() */
static void
pg_stat_statements_internal(FunctionCallInfo fcinfo,
                            pgssVersion api_version,
                            bool showtext)
{
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    Oid         userid = GetUserId();
    bool        is_allowed_role = false;
    char       *qbuffer = NULL;
    Size        qbuffer_size = 0;
    Size        extent = 0;
    int         gc_count = 0;
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
 
    /*
     * Superusers or roles with the privileges of pg_read_all_stats members
     * are allowed
     */
    is_allowed_role = has_privs_of_role(userid, ROLE_PG_READ_ALL_STATS);
 
    /* hash table must exist already */
    if (!pgss || !pgss_hash)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_stat_statements must be loaded via \"shared_preload_libraries\"")));
 
    InitMaterializedSRF(fcinfo, 0);
 
    /*
     * Check we have the expected number of output arguments.  Aside from
     * being a good safety check, we need a kluge here to detect API version
     * 1.1, which was wedged into the code in an ill-considered way.
     */
    switch (rsinfo->setDesc->natts)
    {
        case PG_STAT_STATEMENTS_COLS_V1_0:
            if (api_version != PGSS_V1_0)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_1:
            /* pg_stat_statements() should have told us 1.0 */
            if (api_version != PGSS_V1_0)
                elog(ERROR, "incorrect number of output arguments");
            api_version = PGSS_V1_1;
            break;
        case PG_STAT_STATEMENTS_COLS_V1_2:
            if (api_version != PGSS_V1_2)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_3:
            if (api_version != PGSS_V1_3)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_8:
            if (api_version != PGSS_V1_8)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_9:
            if (api_version != PGSS_V1_9)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_10:
            if (api_version != PGSS_V1_10)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_11:
            if (api_version != PGSS_V1_11)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_12:
            if (api_version != PGSS_V1_12)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_13:
            if (api_version != PGSS_V1_13)
                elog(ERROR, "incorrect number of output arguments");
            break;
        default:
            elog(ERROR, "incorrect number of output arguments");
    }
 
    /*
     * We'd like to load the query text file (if needed) while not holding any
     * lock on pgss->lock.  In the worst case we'll have to do this again
     * after we have the lock, but it's unlikely enough to make this a win
     * despite occasional duplicated work.  We need to reload if anybody
     * writes to the file (either a retail qtext_store(), or a garbage
     * collection) between this point and where we've gotten shared lock.  If
     * a qtext_store is actually in progress when we look, we might as well
     * skip the speculative load entirely.
     */
    if (showtext)
    {
        int         n_writers;
 
        /* Take the mutex so we can examine variables */
        SpinLockAcquire(&pgss->mutex);
        extent = pgss->extent;
        n_writers = pgss->n_writers;
        gc_count = pgss->gc_count;
        SpinLockRelease(&pgss->mutex);
 
        /* No point in loading file now if there are active writers */
        if (n_writers == 0)
            qbuffer = qtext_load_file(&qbuffer_size);
    }
 
    /*
     * Get shared lock, load or reload the query text file if we must, and
     * iterate over the hashtable entries.
     *
     * With a large hash table, we might be holding the lock rather longer
     * than one could wish.  However, this only blocks creation of new hash
     * table entries, and the larger the hash table the less likely that is to
     * be needed.  So we can hope this is okay.  Perhaps someday we'll decide
     * we need to partition the hash table to limit the time spent holding any
     * one lock.
     */
    LWLockAcquire(&pgss->lock.lock, LW_SHARED);
 
    if (showtext)
    {
        /*
         * Here it is safe to examine extent and gc_count without taking the
         * mutex.  Note that although other processes might change
         * pgss->extent just after we look at it, the strings they then write
         * into the file cannot yet be referenced in the hashtable, so we
         * don't care whether we see them or not.
         *
         * If qtext_load_file fails, we just press on; we'll return NULL for
         * every query text.
         */
        if (qbuffer == NULL ||
            pgss->extent != extent ||
            pgss->gc_count != gc_count)
        {
            if (qbuffer)
                pfree(qbuffer);
            qbuffer = qtext_load_file(&qbuffer_size);
        }
    }
 
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        Datum       values[PG_STAT_STATEMENTS_COLS];
        bool        nulls[PG_STAT_STATEMENTS_COLS];
        int         i = 0;
        Counters    tmp;
        double      stddev;
        int64       queryid = entry->key.queryid;
        TimestampTz stats_since;
        TimestampTz minmax_stats_since;
 
        memset(values, 0, sizeof(values));
        memset(nulls, 0, sizeof(nulls));
 
        values[i++] = ObjectIdGetDatum(entry->key.userid);
        values[i++] = ObjectIdGetDatum(entry->key.dbid);
        if (api_version >= PGSS_V1_9)
            values[i++] = BoolGetDatum(entry->key.toplevel);
 
        if (is_allowed_role || entry->key.userid == userid)
        {
            if (api_version >= PGSS_V1_2)
                values[i++] = Int64GetDatumFast(queryid);
 
            if (showtext)
            {
                char       *qstr = qtext_fetch(entry->query_offset,
                                               entry->query_len,
                                               qbuffer,
                                               qbuffer_size);
 
                if (qstr)
                {
                    char       *enc;
 
                    enc = pg_any_to_server(qstr,
                                           entry->query_len,
                                           entry->encoding);
 
                    values[i++] = CStringGetTextDatum(enc);
 
                    if (enc != qstr)
                        pfree(enc);
                }
                else
                {
                    /* Just return a null if we fail to find the text */
                    nulls[i++] = true;
                }
            }
            else
            {
                /* Query text not requested */
                nulls[i++] = true;
            }
        }
        else
        {
            /* Don't show queryid */
            if (api_version >= PGSS_V1_2)
                nulls[i++] = true;
 
            /*
             * Don't show query text, but hint as to the reason for not doing
             * so if it was requested
             */
            if (showtext)
                values[i++] = CStringGetTextDatum("<insufficient privilege>");
            else
                nulls[i++] = true;
        }
 
        /* copy counters to a local variable to keep locking time short */
        SpinLockAcquire(&entry->mutex);
        tmp = entry->counters;
        SpinLockRelease(&entry->mutex);
 
        /*
         * The spinlock is not required when reading these two as they are
         * always updated when holding pgss->lock exclusively.
         */
        stats_since = entry->stats_since;
        minmax_stats_since = entry->minmax_stats_since;
 
        /* Skip entry if unexecuted (ie, it's a pending "sticky" entry) */
        if (IS_STICKY(tmp))
            continue;
 
        /* Note that we rely on PGSS_PLAN being 0 and PGSS_EXEC being 1. */
        for (int kind = 0; kind < PGSS_NUMKIND; kind++)
        {
            if (kind == PGSS_EXEC || api_version >= PGSS_V1_8)
            {
                values[i++] = Int64GetDatumFast(tmp.calls[kind]);
                values[i++] = Float8GetDatumFast(tmp.total_time[kind]);
            }
 
            if ((kind == PGSS_EXEC && api_version >= PGSS_V1_3) ||
                api_version >= PGSS_V1_8)
            {
                values[i++] = Float8GetDatumFast(tmp.min_time[kind]);
                values[i++] = Float8GetDatumFast(tmp.max_time[kind]);
                values[i++] = Float8GetDatumFast(tmp.mean_time[kind]);
 
                /*
                 * Note we are calculating the population variance here, not
                 * the sample variance, as we have data for the whole
                 * population, so Bessel's correction is not used, and we
                 * don't divide by tmp.calls - 1.
                 */
                if (tmp.calls[kind] > 1)
                    stddev = sqrt(tmp.sum_var_time[kind] / tmp.calls[kind]);
                else
                    stddev = 0.0;
                values[i++] = Float8GetDatumFast(stddev);
            }
        }
        values[i++] = Int64GetDatumFast(tmp.rows);
        values[i++] = Int64GetDatumFast(tmp.shared_blks_hit);
        values[i++] = Int64GetDatumFast(tmp.shared_blks_read);
        if (api_version >= PGSS_V1_1)
            values[i++] = Int64GetDatumFast(tmp.shared_blks_dirtied);
        values[i++] = Int64GetDatumFast(tmp.shared_blks_written);
        values[i++] = Int64GetDatumFast(tmp.local_blks_hit);
        values[i++] = Int64GetDatumFast(tmp.local_blks_read);
        if (api_version >= PGSS_V1_1)
            values[i++] = Int64GetDatumFast(tmp.local_blks_dirtied);
        values[i++] = Int64GetDatumFast(tmp.local_blks_written);
        values[i++] = Int64GetDatumFast(tmp.temp_blks_read);
        values[i++] = Int64GetDatumFast(tmp.temp_blks_written);
        if (api_version >= PGSS_V1_1)
        {
            values[i++] = Float8GetDatumFast(tmp.shared_blk_read_time);
            values[i++] = Float8GetDatumFast(tmp.shared_blk_write_time);
        }
        if (api_version >= PGSS_V1_11)
        {
            values[i++] = Float8GetDatumFast(tmp.local_blk_read_time);
            values[i++] = Float8GetDatumFast(tmp.local_blk_write_time);
        }
        if (api_version >= PGSS_V1_10)
        {
            values[i++] = Float8GetDatumFast(tmp.temp_blk_read_time);
            values[i++] = Float8GetDatumFast(tmp.temp_blk_write_time);
        }
        if (api_version >= PGSS_V1_8)
        {
            char        buf[256];
            Datum       wal_bytes;
 
            values[i++] = Int64GetDatumFast(tmp.wal_records);
            values[i++] = Int64GetDatumFast(tmp.wal_fpi);
 
            snprintf(buf, sizeof buf, UINT64_FORMAT, tmp.wal_bytes);
 
            /* Convert to numeric. */
            wal_bytes = DirectFunctionCall3(numeric_in,
                                            CStringGetDatum(buf),
                                            ObjectIdGetDatum(0),
                                            Int32GetDatum(-1));
            values[i++] = wal_bytes;
        }
        if (api_version >= PGSS_V1_12)
        {
            values[i++] = Int64GetDatumFast(tmp.wal_buffers_full);
        }
        if (api_version >= PGSS_V1_10)
        {
            values[i++] = Int64GetDatumFast(tmp.jit_functions);
            values[i++] = Float8GetDatumFast(tmp.jit_generation_time);
            values[i++] = Int64GetDatumFast(tmp.jit_inlining_count);
            values[i++] = Float8GetDatumFast(tmp.jit_inlining_time);
            values[i++] = Int64GetDatumFast(tmp.jit_optimization_count);
            values[i++] = Float8GetDatumFast(tmp.jit_optimization_time);
            values[i++] = Int64GetDatumFast(tmp.jit_emission_count);
            values[i++] = Float8GetDatumFast(tmp.jit_emission_time);
        }
        if (api_version >= PGSS_V1_11)
        {
            values[i++] = Int64GetDatumFast(tmp.jit_deform_count);
            values[i++] = Float8GetDatumFast(tmp.jit_deform_time);
        }
        if (api_version >= PGSS_V1_12)
        {
            values[i++] = Int64GetDatumFast(tmp.parallel_workers_to_launch);
            values[i++] = Int64GetDatumFast(tmp.parallel_workers_launched);
        }
        if (api_version >= PGSS_V1_13)
        {
            values[i++] = Int64GetDatumFast(tmp.generic_plan_calls);
            values[i++] = Int64GetDatumFast(tmp.custom_plan_calls);
        }
        if (api_version >= PGSS_V1_11)
        {
            values[i++] = TimestampTzGetDatum(stats_since);
            values[i++] = TimestampTzGetDatum(minmax_stats_since);
        }
 
        Assert(i == (api_version == PGSS_V1_0 ? PG_STAT_STATEMENTS_COLS_V1_0 :
                     api_version == PGSS_V1_1 ? PG_STAT_STATEMENTS_COLS_V1_1 :
                     api_version == PGSS_V1_2 ? PG_STAT_STATEMENTS_COLS_V1_2 :
                     api_version == PGSS_V1_3 ? PG_STAT_STATEMENTS_COLS_V1_3 :
                     api_version == PGSS_V1_8 ? PG_STAT_STATEMENTS_COLS_V1_8 :
                     api_version == PGSS_V1_9 ? PG_STAT_STATEMENTS_COLS_V1_9 :
                     api_version == PGSS_V1_10 ? PG_STAT_STATEMENTS_COLS_V1_10 :
                     api_version == PGSS_V1_11 ? PG_STAT_STATEMENTS_COLS_V1_11 :
                     api_version == PGSS_V1_12 ? PG_STAT_STATEMENTS_COLS_V1_12 :
                     api_version == PGSS_V1_13 ? PG_STAT_STATEMENTS_COLS_V1_13 :
                     -1 /* fail if you forget to update this assert */ ));
 
        tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
    }
 
    LWLockRelease(&pgss->lock.lock);
 
    if (qbuffer)
        pfree(qbuffer);
}
 
/* Number of output arguments (columns) for pg_stat_statements_info */
#define PG_STAT_STATEMENTS_INFO_COLS    2
 
/*
 * Return statistics of pg_stat_statements.
 */
Datum
pg_stat_statements_info(PG_FUNCTION_ARGS)
{
    pgssGlobalStats stats;
    TupleDesc   tupdesc;
    Datum       values[PG_STAT_STATEMENTS_INFO_COLS] = {0};
    bool        nulls[PG_STAT_STATEMENTS_INFO_COLS] = {0};
 
    if (!pgss || !pgss_hash)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_stat_statements must be loaded via \"shared_preload_libraries\"")));
 
    /* Build a tuple descriptor for our result type */
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* Read global statistics for pg_stat_statements */
    SpinLockAcquire(&pgss->mutex);
    stats = pgss->stats;
    SpinLockRelease(&pgss->mutex);
 
    values[0] = Int64GetDatum(stats.dealloc);
    values[1] = TimestampTzGetDatum(stats.stats_reset);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}
 
/*
 * Allocate a new hashtable entry.
 * caller must hold an exclusive lock on pgss->lock
 *
 * "query" need not be null-terminated; we rely on query_len instead
 *
 * If "sticky" is true, make the new entry artificially sticky so that it will
 * probably still be there when the query finishes execution.  We do this by
 * giving it a median usage value rather than the normal value.  (Strictly
 * speaking, query strings are normalized on a best effort basis, though it
 * would be difficult to demonstrate this even under artificial conditions.)
 *
 * Note: despite needing exclusive lock, it's not an error for the target
 * entry to already exist.  This is because pgss_store releases and
 * reacquires lock after failing to find a match; so someone else could
 * have made the entry while we waited to get exclusive lock.
 */
static pgssEntry *
entry_alloc(pgssHashKey *key, Size query_offset, int query_len, int encoding,
            bool sticky)
{
    pgssEntry  *entry;
    bool        found;
 
    /* Make space if needed */
    while (hash_get_num_entries(pgss_hash) >= pgss_max)
        entry_dealloc();
 
    /* Find or create an entry with desired hash code */
    entry = (pgssEntry *) hash_search(pgss_hash, key, HASH_ENTER, &found);
 
    if (!found)
    {
        /* New entry, initialize it */
 
        /* reset the statistics */
        memset(&entry->counters, 0, sizeof(Counters));
        /* set the appropriate initial usage count */
        entry->counters.usage = sticky ? pgss->cur_median_usage : USAGE_INIT;
        /* re-initialize the mutex each time ... we assume no one using it */
        SpinLockInit(&entry->mutex);
        /* ... and don't forget the query text metadata */
        Assert(query_len >= 0);
        entry->query_offset = query_offset;
        entry->query_len = query_len;
        entry->encoding = encoding;
        entry->stats_since = GetCurrentTimestamp();
        entry->minmax_stats_since = entry->stats_since;
    }
 
    return entry;
}
 
/*
 * qsort comparator for sorting into increasing usage order
 */
static int
entry_cmp(const void *lhs, const void *rhs)
{
    double      l_usage = (*(pgssEntry *const *) lhs)->counters.usage;
    double      r_usage = (*(pgssEntry *const *) rhs)->counters.usage;
 
    if (l_usage < r_usage)
        return -1;
    else if (l_usage > r_usage)
        return +1;
    else
        return 0;
}
 
/*
 * Deallocate least-used entries.
 *
 * Caller must hold an exclusive lock on pgss->lock.
 */
static void
entry_dealloc(void)
{
    HASH_SEQ_STATUS hash_seq;
    pgssEntry **entries;
    pgssEntry  *entry;
    int         nvictims;
    int         i;
    Size        tottextlen;
    int         nvalidtexts;
 
    /*
     * Sort entries by usage and deallocate USAGE_DEALLOC_PERCENT of them.
     * While we're scanning the table, apply the decay factor to the usage
     * values, and update the mean query length.
     *
     * Note that the mean query length is almost immediately obsolete, since
     * we compute it before not after discarding the least-used entries.
     * Hopefully, that doesn't affect the mean too much; it doesn't seem worth
     * making two passes to get a more current result.  Likewise, the new
     * cur_median_usage includes the entries we're about to zap.
     */
 
    entries = palloc(hash_get_num_entries(pgss_hash) * sizeof(pgssEntry *));
 
    i = 0;
    tottextlen = 0;
    nvalidtexts = 0;
 
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        entries[i++] = entry;
        /* "Sticky" entries get a different usage decay rate. */
        if (IS_STICKY(entry->counters))
            entry->counters.usage *= STICKY_DECREASE_FACTOR;
        else
            entry->counters.usage *= USAGE_DECREASE_FACTOR;
        /* In the mean length computation, ignore dropped texts. */
        if (entry->query_len >= 0)
        {
            tottextlen += entry->query_len + 1;
            nvalidtexts++;
        }
    }
 
    /* Sort into increasing order by usage */
    qsort(entries, i, sizeof(pgssEntry *), entry_cmp);
 
    /* Record the (approximate) median usage */
    if (i > 0)
        pgss->cur_median_usage = entries[i / 2]->counters.usage;
    /* Record the mean query length */
    if (nvalidtexts > 0)
        pgss->mean_query_len = tottextlen / nvalidtexts;
    else
        pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
    /* Now zap an appropriate fraction of lowest-usage entries */
    nvictims = Max(10, i * USAGE_DEALLOC_PERCENT / 100);
    nvictims = Min(nvictims, i);
 
    for (i = 0; i < nvictims; i++)
    {
        hash_search(pgss_hash, &entries[i]->key, HASH_REMOVE, NULL);
    }
 
    pfree(entries);
 
    /* Increment the number of times entries are deallocated */
    SpinLockAcquire(&pgss->mutex);
    pgss->stats.dealloc += 1;
    SpinLockRelease(&pgss->mutex);
}
 
/*
 * Given a query string (not necessarily null-terminated), allocate a new
 * entry in the external query text file and store the string there.
 *
 * If successful, returns true, and stores the new entry's offset in the file
 * into *query_offset.  Also, if gc_count isn't NULL, *gc_count is set to the
 * number of garbage collections that have occurred so far.
 *
 * On failure, returns false.
 *
 * At least a shared lock on pgss->lock must be held by the caller, so as
 * to prevent a concurrent garbage collection.  Share-lock-holding callers
 * should pass a gc_count pointer to obtain the number of garbage collections,
 * so that they can recheck the count after obtaining exclusive lock to
 * detect whether a garbage collection occurred (and removed this entry).
 */
static bool
qtext_store(const char *query, int query_len,
            Size *query_offset, int *gc_count)
{
    Size        off;
    int         fd;
 
    /*
     * We use a spinlock to protect extent/n_writers/gc_count, so that
     * multiple processes may execute this function concurrently.
     */
    SpinLockAcquire(&pgss->mutex);
    off = pgss->extent;
    pgss->extent += query_len + 1;
    pgss->n_writers++;
    if (gc_count)
        *gc_count = pgss->gc_count;
    SpinLockRelease(&pgss->mutex);
 
    *query_offset = off;
 
    /*
     * Don't allow the file to grow larger than what qtext_load_file can
     * (theoretically) handle.  This has been seen to be reachable on 32-bit
     * platforms.
     */
    if (unlikely(query_len >= MaxAllocHugeSize - off))
    {
        errno = EFBIG;          /* not quite right, but it'll do */
        fd = -1;
        goto error;
    }
 
    /* Now write the data into the successfully-reserved part of the file */
    fd = OpenTransientFile(PGSS_TEXT_FILE, O_RDWR | O_CREAT | PG_BINARY);
    if (fd < 0)
        goto error;
 
    if (pg_pwrite(fd, query, query_len, off) != query_len)
        goto error;
    if (pg_pwrite(fd, "\0", 1, off + query_len) != 1)
        goto error;
 
    CloseTransientFile(fd);
 
    /* Mark our write complete */
    SpinLockAcquire(&pgss->mutex);
    pgss->n_writers--;
    SpinLockRelease(&pgss->mutex);
 
    return true;
 
error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not write file \"%s\": %m",
                    PGSS_TEXT_FILE)));
 
    if (fd >= 0)
        CloseTransientFile(fd);
 
    /* Mark our write complete */
    SpinLockAcquire(&pgss->mutex);
    pgss->n_writers--;
    SpinLockRelease(&pgss->mutex);
 
    return false;
}
 
/*
 * Read the external query text file into a palloc'd buffer.
 *
 * Returns NULL (without throwing an error) if unable to read, eg
 * file not there or insufficient memory.
 *
 * On success, the buffer size is also returned into *buffer_size.
 *
 * This can be called without any lock on pgss->lock, but in that case
 * the caller is responsible for verifying that the result is sane.
 */
static char *
qtext_load_file(Size *buffer_size)
{
    char       *buf;
    int         fd;
    struct stat stat;
    Size        nread;
 
    fd = OpenTransientFile(PGSS_TEXT_FILE, O_RDONLY | PG_BINARY);
    if (fd < 0)
    {
        if (errno != ENOENT)
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not read file \"%s\": %m",
                            PGSS_TEXT_FILE)));
        return NULL;
    }
 
    /* Get file length */
    if (fstat(fd, &stat))
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not stat file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        CloseTransientFile(fd);
        return NULL;
    }
 
    /* Allocate buffer; beware that off_t might be wider than size_t */
    if (stat.st_size <= MaxAllocHugeSize)
        buf = (char *) palloc_extended(stat.st_size, MCXT_ALLOC_HUGE | MCXT_ALLOC_NO_OOM);
    else
        buf = NULL;
    if (buf == NULL)
    {
        ereport(LOG,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("out of memory"),
                 errdetail("Could not allocate enough memory to read file \"%s\".",
                           PGSS_TEXT_FILE)));
        CloseTransientFile(fd);
        return NULL;
    }
 
    /*
     * OK, slurp in the file.  Windows fails if we try to read more than
     * INT_MAX bytes at once, and other platforms might not like that either,
     * so read a very large file in 1GB segments.
     */
    nread = 0;
    while (nread < stat.st_size)
    {
        int         toread = Min(1024 * 1024 * 1024, stat.st_size - nread);
 
        /*
         * If we get a short read and errno doesn't get set, the reason is
         * probably that garbage collection truncated the file since we did
         * the fstat(), so we don't log a complaint --- but we don't return
         * the data, either, since it's most likely corrupt due to concurrent
         * writes from garbage collection.
         */
        errno = 0;
        if (read(fd, buf + nread, toread) != toread)
        {
            if (errno)
                ereport(LOG,
                        (errcode_for_file_access(),
                         errmsg("could not read file \"%s\": %m",
                                PGSS_TEXT_FILE)));
            pfree(buf);
            CloseTransientFile(fd);
            return NULL;
        }
        nread += toread;
    }
 
    if (CloseTransientFile(fd) != 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not close file \"%s\": %m", PGSS_TEXT_FILE)));
 
    *buffer_size = nread;
    return buf;
}
 
/*
 * Locate a query text in the file image previously read by qtext_load_file().
 *
 * We validate the given offset/length, and return NULL if bogus.  Otherwise,
 * the result points to a null-terminated string within the buffer.
 */
static char *
qtext_fetch(Size query_offset, int query_len,
            char *buffer, Size buffer_size)
{
    /* File read failed? */
    if (buffer == NULL)
        return NULL;
    /* Bogus offset/length? */
    if (query_len < 0 ||
        query_offset + query_len >= buffer_size)
        return NULL;
    /* As a further sanity check, make sure there's a trailing null */
    if (buffer[query_offset + query_len] != '\0')
        return NULL;
    /* Looks OK */
    return buffer + query_offset;
}
 
/*
 * Do we need to garbage-collect the external query text file?
 *
 * Caller should hold at least a shared lock on pgss->lock.
 */
static bool
need_gc_qtexts(void)
{
    Size        extent;
 
    /* Read shared extent pointer */
    SpinLockAcquire(&pgss->mutex);
    extent = pgss->extent;
    SpinLockRelease(&pgss->mutex);
 
    /*
     * Don't proceed if file does not exceed 512 bytes per possible entry.
     *
     * Here and in the next test, 32-bit machines have overflow hazards if
     * pgss_max and/or mean_query_len are large.  Force the multiplications
     * and comparisons to be done in uint64 arithmetic to forestall trouble.
     */
    if ((uint64) extent < (uint64) 512 * pgss_max)
        return false;
 
    /*
     * Don't proceed if file is less than about 50% bloat.  Nothing can or
     * should be done in the event of unusually large query texts accounting
     * for file's large size.  We go to the trouble of maintaining the mean
     * query length in order to prevent garbage collection from thrashing
     * uselessly.
     */
    if ((uint64) extent < (uint64) pgss->mean_query_len * pgss_max * 2)
        return false;
 
    return true;
}
 
/*
 * Garbage-collect orphaned query texts in external file.
 *
 * This won't be called often in the typical case, since it's likely that
 * there won't be too much churn, and besides, a similar compaction process
 * occurs when serializing to disk at shutdown or as part of resetting.
 * Despite this, it seems prudent to plan for the edge case where the file
 * becomes unreasonably large, with no other method of compaction likely to
 * occur in the foreseeable future.
 *
 * The caller must hold an exclusive lock on pgss->lock.
 *
 * At the first sign of trouble we unlink the query text file to get a clean
 * slate (although existing statistics are retained), rather than risk
 * thrashing by allowing the same problem case to recur indefinitely.
 */
static void
gc_qtexts(void)
{
    char       *qbuffer;
    Size        qbuffer_size;
    FILE       *qfile = NULL;
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
    Size        extent;
    int         nentries;
 
    /*
     * When called from pgss_store, some other session might have proceeded
     * with garbage collection in the no-lock-held interim of lock strength
     * escalation.  Check once more that this is actually necessary.
     */
    if (!need_gc_qtexts())
        return;
 
    /*
     * Load the old texts file.  If we fail (out of memory, for instance),
     * invalidate query texts.  Hopefully this is rare.  It might seem better
     * to leave things alone on an OOM failure, but the problem is that the
     * file is only going to get bigger; hoping for a future non-OOM result is
     * risky and can easily lead to complete denial of service.
     */
    qbuffer = qtext_load_file(&qbuffer_size);
    if (qbuffer == NULL)
        goto gc_fail;
 
    /*
     * We overwrite the query texts file in place, so as to reduce the risk of
     * an out-of-disk-space failure.  Since the file is guaranteed not to get
     * larger, this should always work on traditional filesystems; though we
     * could still lose on copy-on-write filesystems.
     */
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not write file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        goto gc_fail;
    }
 
    extent = 0;
    nentries = 0;
 
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        int         query_len = entry->query_len;
        char       *qry = qtext_fetch(entry->query_offset,
                                      query_len,
                                      qbuffer,
                                      qbuffer_size);
 
        if (qry == NULL)
        {
            /* Trouble ... drop the text */
            entry->query_offset = 0;
            entry->query_len = -1;
            /* entry will not be counted in mean query length computation */
            continue;
        }
 
        if (fwrite(qry, 1, query_len + 1, qfile) != query_len + 1)
        {
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not write file \"%s\": %m",
                            PGSS_TEXT_FILE)));
            hash_seq_term(&hash_seq);
            goto gc_fail;
        }
 
        entry->query_offset = extent;
        extent += query_len + 1;
        nentries++;
    }
 
    /*
     * Truncate away any now-unused space.  If this fails for some odd reason,
     * we log it, but there's no need to fail.
     */
    if (ftruncate(fileno(qfile), extent) != 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not truncate file \"%s\": %m",
                        PGSS_TEXT_FILE)));
 
    if (FreeFile(qfile))
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not write file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        qfile = NULL;
        goto gc_fail;
    }
 
    elog(DEBUG1, "pgss gc of queries file shrunk size from %zu to %zu",
         pgss->extent, extent);
 
    /* Reset the shared extent pointer */
    pgss->extent = extent;
 
    /*
     * Also update the mean query length, to be sure that need_gc_qtexts()
     * won't still think we have a problem.
     */
    if (nentries > 0)
        pgss->mean_query_len = extent / nentries;
    else
        pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
    pfree(qbuffer);
 
    /*
     * OK, count a garbage collection cycle.  (Note: even though we have
     * exclusive lock on pgss->lock, we must take pgss->mutex for this, since
     * other processes may examine gc_count while holding only the mutex.
     * Also, we have to advance the count *after* we've rewritten the file,
     * else other processes might not realize they read a stale file.)
     */
    record_gc_qtexts();
 
    return;
 
gc_fail:
    /* clean up resources */
    if (qfile)
        FreeFile(qfile);
    if (qbuffer)
        pfree(qbuffer);
 
    /*
     * Since the contents of the external file are now uncertain, mark all
     * hashtable entries as having invalid texts.
     */
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        entry->query_offset = 0;
        entry->query_len = -1;
    }
 
    /*
     * Destroy the query text file and create a new, empty one
     */
    (void) unlink(PGSS_TEXT_FILE);
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not recreate file \"%s\": %m",
                        PGSS_TEXT_FILE)));
    else
        FreeFile(qfile);
 
    /* Reset the shared extent pointer */
    pgss->extent = 0;
 
    /* Reset mean_query_len to match the new state */
    pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
    /*
     * Bump the GC count even though we failed.
     *
     * This is needed to make concurrent readers of file without any lock on
     * pgss->lock notice existence of new version of file.  Once readers
     * subsequently observe a change in GC count with pgss->lock held, that
     * forces a safe reopen of file.  Writers also require that we bump here,
     * of course.  (As required by locking protocol, readers and writers don't
     * trust earlier file contents until gc_count is found unchanged after
     * pgss->lock acquired in shared or exclusive mode respectively.)
     */
    record_gc_qtexts();
}
 
#define SINGLE_ENTRY_RESET(e) \
if (e) { \
    if (minmax_only) { \
        /* When requested reset only min/max statistics of an entry */ \
        for (int kind = 0; kind < PGSS_NUMKIND; kind++) \
        { \
            e->counters.max_time[kind] = 0; \
            e->counters.min_time[kind] = 0; \
        } \
        e->minmax_stats_since = stats_reset; \
    } \
    else \
    { \
        /* Remove the key otherwise  */ \
        hash_search(pgss_hash, &e->key, HASH_REMOVE, NULL); \
        num_remove++; \
    } \
}
 
/*
 * Reset entries corresponding to parameters passed.
 */
static TimestampTz
entry_reset(Oid userid, Oid dbid, int64 queryid, bool minmax_only)
{
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
    FILE       *qfile;
    int64       num_entries;
    int64       num_remove = 0;
    pgssHashKey key;
    TimestampTz stats_reset;
 
    if (!pgss || !pgss_hash)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_stat_statements must be loaded via \"shared_preload_libraries\"")));
 
    LWLockAcquire(&pgss->lock.lock, LW_EXCLUSIVE);
    num_entries = hash_get_num_entries(pgss_hash);
 
    stats_reset = GetCurrentTimestamp();
 
    if (userid != 0 && dbid != 0 && queryid != INT64CONST(0))
    {
        /* If all the parameters are available, use the fast path. */
        memset(&key, 0, sizeof(pgssHashKey));
        key.userid = userid;
        key.dbid = dbid;
        key.queryid = queryid;
 
        /*
         * Reset the entry if it exists, starting with the non-top-level
         * entry.
         */
        key.toplevel = false;
        entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
 
        SINGLE_ENTRY_RESET(entry);
 
        /* Also reset the top-level entry if it exists. */
        key.toplevel = true;
        entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
 
        SINGLE_ENTRY_RESET(entry);
    }
    else if (userid != 0 || dbid != 0 || queryid != INT64CONST(0))
    {
        /* Reset entries corresponding to valid parameters. */
        hash_seq_init(&hash_seq, pgss_hash);
        while ((entry = hash_seq_search(&hash_seq)) != NULL)
        {
            if ((!userid || entry->key.userid == userid) &&
                (!dbid || entry->key.dbid == dbid) &&
                (!queryid || entry->key.queryid == queryid))
            {
                SINGLE_ENTRY_RESET(entry);
            }
        }
    }
    else
    {
        /* Reset all entries. */
        hash_seq_init(&hash_seq, pgss_hash);
        while ((entry = hash_seq_search(&hash_seq)) != NULL)
        {
            SINGLE_ENTRY_RESET(entry);
        }
    }
 
    /* All entries are removed? */
    if (num_entries != num_remove)
        goto release_lock;
 
    /*
     * Reset global statistics for pg_stat_statements since all entries are
     * removed.
     */
    SpinLockAcquire(&pgss->mutex);
    pgss->stats.dealloc = 0;
    pgss->stats.stats_reset = stats_reset;
    SpinLockRelease(&pgss->mutex);
 
    /*
     * Write new empty query file, perhaps even creating a new one to recover
     * if the file was missing.
     */
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not create file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        goto done;
    }
 
    /* If ftruncate fails, log it, but it's not a fatal problem */
    if (ftruncate(fileno(qfile), 0) != 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not truncate file \"%s\": %m",
                        PGSS_TEXT_FILE)));
 
    FreeFile(qfile);
 
done:
    pgss->extent = 0;
    /* This counts as a query text garbage collection for our purposes */
    record_gc_qtexts();
 
release_lock:
    LWLockRelease(&pgss->lock.lock);
 
    return stats_reset;
}
 
/*
 * Generate a normalized version of the query string that will be used to
 * represent all similar queries.
 *
 * Note that the normalized representation may well vary depending on
 * just which "equivalent" query is used to create the hashtable entry.
 * We assume this is OK.
 *
 * If query_loc > 0, then "query" has been advanced by that much compared to
 * the original string start, so we need to translate the provided locations
 * to compensate.  (This lets us avoid re-scanning statements before the one
 * of interest, so it's worth doing.)
 *
 * *query_len_p contains the input string length, and is updated with
 * the result string length on exit.  The resulting string might be longer
 * or shorter depending on what happens with replacement of constants.
 *
 * Returns a palloc'd string.
 */
static char *
generate_normalized_query(const JumbleState *jstate, const char *query,
                          int query_loc, int *query_len_p)
{
    char       *norm_query;
    int         query_len = *query_len_p;
    int         norm_query_buflen,  /* Space allowed for norm_query */
                len_to_wrt,     /* Length (in bytes) to write */
                quer_loc = 0,   /* Source query byte location */
                n_quer_loc = 0, /* Normalized query byte location */
                last_off = 0,   /* Offset from start for previous tok */
                last_tok_len = 0;   /* Length (in bytes) of that tok */
    int         num_constants_replaced = 0;
    LocationLen *locs = NULL;
 
    /*
     * Determine constants' lengths (core system only gives us locations), and
     * return a sorted copy of jstate's LocationLen data with lengths filled
     * in.
     */
    locs = ComputeConstantLengths(jstate, query, query_loc);
 
    /*
     * Allow for $n symbols to be longer than the constants they replace.
     * Constants must take at least one byte in text form, while a $n symbol
     * certainly isn't more than 11 bytes, even if n reaches INT_MAX.  We
     * could refine that limit based on the max value of n for the current
     * query, but it hardly seems worth any extra effort to do so.
     */
    norm_query_buflen = query_len + jstate->clocations_count * 10;
 
    /* Allocate result buffer */
    norm_query = palloc(norm_query_buflen + 1);
 
    for (int i = 0; i < jstate->clocations_count; i++)
    {
        int         off,        /* Offset from start for cur tok */
                    tok_len;    /* Length (in bytes) of that tok */
 
        /*
         * If we have an external param at this location, but no lists are
         * being squashed across the query, then we skip here; this will make
         * us print the characters found in the original query that represent
         * the parameter in the next iteration (or after the loop is done),
         * which is a bit odd but seems to work okay in most cases.
         */
        if (locs[i].extern_param && !jstate->has_squashed_lists)
            continue;
 
        off = locs[i].location;
 
        /* Adjust recorded location if we're dealing with partial string */
        off -= query_loc;
 
        tok_len = locs[i].length;
 
        if (tok_len < 0)
            continue;           /* ignore any duplicates */
 
        /* Copy next chunk (what precedes the next constant) */
        len_to_wrt = off - last_off;
        len_to_wrt -= last_tok_len;
        Assert(len_to_wrt >= 0);
        memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
        n_quer_loc += len_to_wrt;
 
        /*
         * And insert a param symbol in place of the constant token; and, if
         * we have a squashable list, insert a placeholder comment starting
         * from the list's second value.
         */
        n_quer_loc += sprintf(norm_query + n_quer_loc, "$%d%s",
                              num_constants_replaced + 1 + jstate->highest_extern_param_id,
                              locs[i].squashed ? " /*, ... */" : "");
        num_constants_replaced++;
 
        /* move forward */
        quer_loc = off + tok_len;
        last_off = off;
        last_tok_len = tok_len;
    }
 
    /* Clean up, if needed */
    if (locs)
        pfree(locs);
 
    /*
     * We've copied up until the last ignorable constant.  Copy over the
     * remaining bytes of the original query string.
     */
    len_to_wrt = query_len - quer_loc;
 
    Assert(len_to_wrt >= 0);
    memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
    n_quer_loc += len_to_wrt;
 
    Assert(n_quer_loc <= norm_query_buflen);
    norm_query[n_quer_loc] = '\0';
 
    *query_len_p = n_quer_loc;
    return norm_query;
}

PGSS_NUMKIND

#define PGSS_NUMKIND   (PGSS_EXEC + 1)

Definition at line 133 of file pg_stat_statements.c.

PGSS_TEXT_FILE

#define PGSS_TEXT_FILE   PG_STAT_TMP_DIR "/pgss_query_texts.stat"

Definition at line 85 of file pg_stat_statements.c.

record_gc_qtexts

#define record_gc_qtexts

(

)

Value:

    do { \
		SpinLockAcquire(&pgss->mutex); \
        pgss->gc_count++; \
		SpinLockRelease(&pgss->mutex); \
    } while(0)

Definition at line 315 of file pg_stat_statements.c.

       { \
		SpinLockAcquire(&pgss->mutex); \
        pgss->gc_count++; \
		SpinLockRelease(&pgss->mutex); \
    } while(0)

SINGLE_ENTRY_RESET

#define SINGLE_ENTRY_RESET

(

e

)

Value:

if (e) { \
	if (minmax_only) { \
        /* When requested reset only min/max statistics of an entry */ \
		for (int kind = 0; kind < PGSS_NUMKIND; kind++) \
        { \
            e->counters.max_time[kind] = 0; \
            e->counters.min_time[kind] = 0; \
        } \
        e->minmax_stats_since = stats_reset; \
    } \
    else \
    { \
        /* Remove the key otherwise  */ \
		hash_search(pgss_hash, &e->key, HASH_REMOVE, NULL); \
        num_remove++; \
    } \
}

Definition at line 2654 of file pg_stat_statements.c.

       { \
	if (minmax_only) { \
        /* When requested reset only min/max statistics of an entry */ \
		for (int kind = 0; kind < PGSS_NUMKIND; kind++) \
        { \
            e->counters.max_time[kind] = 0; \
            e->counters.min_time[kind] = 0; \
        } \
        e->minmax_stats_since = stats_reset; \
    } \
    else \
    { \
        /* Remove the key otherwise  */ \
		hash_search(pgss_hash, &e->key, HASH_REMOVE, NULL); \
        num_remove++; \
    } \
}

STICKY_DECREASE_FACTOR

#define STICKY_DECREASE_FACTOR   (0.50) /* factor for sticky entries */

Definition at line 99 of file pg_stat_statements.c.

USAGE_DEALLOC_PERCENT

#define USAGE_DEALLOC_PERCENT   5 /* free this % of entries at once */

Definition at line 100 of file pg_stat_statements.c.

USAGE_DECREASE_FACTOR

#define USAGE_DECREASE_FACTOR   (0.99) /* decreased every entry_dealloc */

Definition at line 98 of file pg_stat_statements.c.

USAGE_EXEC

#define USAGE_EXEC

(

duration

)

(1.0)

Definition at line 94 of file pg_stat_statements.c.

USAGE_INIT

#define USAGE_INIT   (1.0) /* including initial planning */

Definition at line 95 of file pg_stat_statements.c.

Typedef Documentation

Counters

typedef struct Counters Counters

pgssEntry

typedef struct pgssEntry pgssEntry

pgssGlobalStats

typedef struct pgssGlobalStats pgssGlobalStats

pgssHashKey

typedef struct pgssHashKey pgssHashKey

pgssSharedState

typedef struct pgssSharedState pgssSharedState

pgssStoreKind

typedef enum pgssStoreKind pgssStoreKind

pgssVersion

typedef enum pgssVersion pgssVersion

Enumeration Type Documentation

pgssStoreKind

enum pgssStoreKind

Enumerator
PGSS_INVALID
PGSS_PLAN
PGSS_EXEC

Definition at line 120 of file pg_stat_statements.c.

{
    PGSS_INVALID = -1,
 
    /*
     * PGSS_PLAN and PGSS_EXEC must be respectively 0 and 1 as they're used to
     * reference the underlying values in the arrays in the Counters struct,
     * and this order is required in pg_stat_statements_internal().
     */
    PGSS_PLAN = 0,
    PGSS_EXEC,
} pgssStoreKind;

PGSSTrackLevel

enum PGSSTrackLevel

Enumerator
PGSS_TRACK_NONE
PGSS_TRACK_TOP
PGSS_TRACK_ALL

Definition at line 288 of file pg_stat_statements.c.

{
    PGSS_TRACK_NONE,            /* track no statements */
    PGSS_TRACK_TOP,             /* only top level statements */
    PGSS_TRACK_ALL,             /* all statements, including nested ones */
}           PGSSTrackLevel;

pgssVersion

enum pgssVersion

Enumerator
PGSS_V1_0
PGSS_V1_1
PGSS_V1_2
PGSS_V1_3
PGSS_V1_8
PGSS_V1_9
PGSS_V1_10
PGSS_V1_11
PGSS_V1_12
PGSS_V1_13

Definition at line 106 of file pg_stat_statements.c.

{
    PGSS_V1_0 = 0,
    PGSS_V1_1,
    PGSS_V1_2,
    PGSS_V1_3,
    PGSS_V1_8,
    PGSS_V1_9,
    PGSS_V1_10,
    PGSS_V1_11,
    PGSS_V1_12,
    PGSS_V1_13,
} pgssVersion;

Function Documentation

_PG_init()

void _PG_init

(

void

)

Definition at line 390 of file pg_stat_statements.c.

{
    /*
     * In order to create our shared memory area, we have to be loaded via
     * shared_preload_libraries.  If not, fall out without hooking into any of
     * the main system.  (We don't throw error here because it seems useful to
     * allow the pg_stat_statements functions to be created even when the
     * module isn't active.  The functions must protect themselves against
     * being called then, however.)
     */
    if (!process_shared_preload_libraries_in_progress)
        return;
 
    /*
     * Inform the postmaster that we want to enable query_id calculation if
     * compute_query_id is set to auto.
     */
    EnableQueryId();
 
    /*
     * Define (or redefine) custom GUC variables.
     */
    DefineCustomIntVariable("pg_stat_statements.max",
                            "Sets the maximum number of statements tracked by pg_stat_statements.",
                            NULL,
                            &pgss_max,
                            5000,
                            100,
                            INT_MAX / 2,
                            PGC_POSTMASTER,
                            0,
                            NULL,
                            NULL,
                            NULL);
 
    DefineCustomEnumVariable("pg_stat_statements.track",
                             "Selects which statements are tracked by pg_stat_statements.",
                             NULL,
                             &pgss_track,
                             PGSS_TRACK_TOP,
                             track_options,
                             PGC_SUSET,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    DefineCustomBoolVariable("pg_stat_statements.track_utility",
                             "Selects whether utility commands are tracked by pg_stat_statements.",
                             NULL,
                             &pgss_track_utility,
                             true,
                             PGC_SUSET,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    DefineCustomBoolVariable("pg_stat_statements.track_planning",
                             "Selects whether planning duration is tracked by pg_stat_statements.",
                             NULL,
                             &pgss_track_planning,
                             false,
                             PGC_SUSET,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    DefineCustomBoolVariable("pg_stat_statements.save",
                             "Save pg_stat_statements statistics across server shutdowns.",
                             NULL,
                             &pgss_save,
                             true,
                             PGC_SIGHUP,
                             0,
                             NULL,
                             NULL,
                             NULL);
 
    MarkGUCPrefixReserved("pg_stat_statements");
 
    /*
     * Register our shared memory needs.
     */
    RegisterShmemCallbacks(&pgss_shmem_callbacks);
 
    /*
     * Install hooks.
     */
    prev_post_parse_analyze_hook = post_parse_analyze_hook;
    post_parse_analyze_hook = pgss_post_parse_analyze;
    prev_planner_hook = planner_hook;
    planner_hook = pgss_planner;
    prev_ExecutorStart = ExecutorStart_hook;
    ExecutorStart_hook = pgss_ExecutorStart;
    prev_ExecutorRun = ExecutorRun_hook;
    ExecutorRun_hook = pgss_ExecutorRun;
    prev_ExecutorFinish = ExecutorFinish_hook;
    ExecutorFinish_hook = pgss_ExecutorFinish;
    prev_ExecutorEnd = ExecutorEnd_hook;
    ExecutorEnd_hook = pgss_ExecutorEnd;
    prev_ProcessUtility = ProcessUtility_hook;
    ProcessUtility_hook = pgss_ProcessUtility;
}

References DefineCustomBoolVariable(), DefineCustomEnumVariable(), DefineCustomIntVariable(), EnableQueryId(), ExecutorEnd_hook, ExecutorFinish_hook, ExecutorRun_hook, ExecutorStart_hook, fb(), MarkGUCPrefixReserved(), PGC_POSTMASTER, PGC_SIGHUP, PGC_SUSET, pgss_ExecutorEnd(), pgss_ExecutorFinish(), pgss_ExecutorRun(), pgss_ExecutorStart(), pgss_max, pgss_planner(), pgss_post_parse_analyze(), pgss_ProcessUtility(), pgss_save, pgss_shmem_callbacks, pgss_track, pgss_track_planning, PGSS_TRACK_TOP, pgss_track_utility, planner_hook, post_parse_analyze_hook, prev_ExecutorEnd, prev_ExecutorFinish, prev_ExecutorRun, prev_ExecutorStart, prev_planner_hook, prev_post_parse_analyze_hook, prev_ProcessUtility, process_shared_preload_libraries_in_progress, ProcessUtility_hook, RegisterShmemCallbacks(), and track_options.

entry_alloc()

static pgssEntry * entry_alloc ( pgssHashKey *  key, Size  query_offset, int  query_len, int  encoding, bool  sticky  )

static

Definition at line 2080 of file pg_stat_statements.c.

{
    pgssEntry  *entry;
    bool        found;
 
    /* Make space if needed */
    while (hash_get_num_entries(pgss_hash) >= pgss_max)
        entry_dealloc();
 
    /* Find or create an entry with desired hash code */
    entry = (pgssEntry *) hash_search(pgss_hash, key, HASH_ENTER, &found);
 
    if (!found)
    {
        /* New entry, initialize it */
 
        /* reset the statistics */
        memset(&entry->counters, 0, sizeof(Counters));
        /* set the appropriate initial usage count */
        entry->counters.usage = sticky ? pgss->cur_median_usage : USAGE_INIT;
        /* re-initialize the mutex each time ... we assume no one using it */
        SpinLockInit(&entry->mutex);
        /* ... and don't forget the query text metadata */
        Assert(query_len >= 0);
        entry->query_offset = query_offset;
        entry->query_len = query_len;
        entry->encoding = encoding;
        entry->stats_since = GetCurrentTimestamp();
        entry->minmax_stats_since = entry->stats_since;
    }
 
    return entry;
}

References Assert, pgssEntry::counters, pgssSharedState::cur_median_usage, pgssEntry::encoding, encoding, entry_dealloc(), fb(), GetCurrentTimestamp(), HASH_ENTER, hash_get_num_entries(), hash_search(), pgssEntry::minmax_stats_since, pgssEntry::mutex, pgss, pgss_hash, pgss_max, pgssEntry::query_len, pgssEntry::query_offset, SpinLockInit(), pgssEntry::stats_since, Counters::usage, and USAGE_INIT.

Referenced by pgss_shmem_init(), and pgss_store().

entry_cmp()

static int entry_cmp ( const void *  lhs, const void *  rhs  )

static

Definition at line 2119 of file pg_stat_statements.c.

{
    double      l_usage = (*(pgssEntry *const *) lhs)->counters.usage;
    double      r_usage = (*(pgssEntry *const *) rhs)->counters.usage;
 
    if (l_usage < r_usage)
        return -1;
    else if (l_usage > r_usage)
        return +1;
    else
        return 0;
}

References pgssEntry::counters, fb(), and Counters::usage.

Referenced by entry_dealloc().

entry_dealloc()

static void entry_dealloc ( void  )

static

Definition at line 2138 of file pg_stat_statements.c.

{
    HASH_SEQ_STATUS hash_seq;
    pgssEntry **entries;
    pgssEntry  *entry;
    int         nvictims;
    int         i;
    Size        tottextlen;
    int         nvalidtexts;
 
    /*
     * Sort entries by usage and deallocate USAGE_DEALLOC_PERCENT of them.
     * While we're scanning the table, apply the decay factor to the usage
     * values, and update the mean query length.
     *
     * Note that the mean query length is almost immediately obsolete, since
     * we compute it before not after discarding the least-used entries.
     * Hopefully, that doesn't affect the mean too much; it doesn't seem worth
     * making two passes to get a more current result.  Likewise, the new
     * cur_median_usage includes the entries we're about to zap.
     */
 
    entries = palloc(hash_get_num_entries(pgss_hash) * sizeof(pgssEntry *));
 
    i = 0;
    tottextlen = 0;
    nvalidtexts = 0;
 
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        entries[i++] = entry;
        /* "Sticky" entries get a different usage decay rate. */
        if (IS_STICKY(entry->counters))
            entry->counters.usage *= STICKY_DECREASE_FACTOR;
        else
            entry->counters.usage *= USAGE_DECREASE_FACTOR;
        /* In the mean length computation, ignore dropped texts. */
        if (entry->query_len >= 0)
        {
            tottextlen += entry->query_len + 1;
            nvalidtexts++;
        }
    }
 
    /* Sort into increasing order by usage */
    qsort(entries, i, sizeof(pgssEntry *), entry_cmp);
 
    /* Record the (approximate) median usage */
    if (i > 0)
        pgss->cur_median_usage = entries[i / 2]->counters.usage;
    /* Record the mean query length */
    if (nvalidtexts > 0)
        pgss->mean_query_len = tottextlen / nvalidtexts;
    else
        pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
    /* Now zap an appropriate fraction of lowest-usage entries */
    nvictims = Max(10, i * USAGE_DEALLOC_PERCENT / 100);
    nvictims = Min(nvictims, i);
 
    for (i = 0; i < nvictims; i++)
    {
        hash_search(pgss_hash, &entries[i]->key, HASH_REMOVE, NULL);
    }
 
    pfree(entries);
 
    /* Increment the number of times entries are deallocated */
    SpinLockAcquire(&pgss->mutex);
    pgss->stats.dealloc += 1;
    SpinLockRelease(&pgss->mutex);
}

References ASSUMED_LENGTH_INIT, pgssEntry::counters, pgssSharedState::cur_median_usage, pgssGlobalStats::dealloc, entry_cmp(), fb(), hash_get_num_entries(), HASH_REMOVE, hash_search(), hash_seq_init(), hash_seq_search(), i, IS_STICKY, Max, pgssSharedState::mean_query_len, Min, pgssSharedState::mutex, palloc(), pfree(), pgss, pgss_hash, qsort, pgssEntry::query_len, SpinLockAcquire(), SpinLockRelease(), pgssSharedState::stats, STICKY_DECREASE_FACTOR, Counters::usage, USAGE_DEALLOC_PERCENT, and USAGE_DECREASE_FACTOR.

Referenced by entry_alloc().

entry_reset()

static TimestampTz entry_reset ( Oid  userid, Oid  dbid, int64  queryid, bool  minmax_only  )

static

Definition at line 2677 of file pg_stat_statements.c.

{
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
    FILE       *qfile;
    int64       num_entries;
    int64       num_remove = 0;
    pgssHashKey key;
    TimestampTz stats_reset;
 
    if (!pgss || !pgss_hash)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_stat_statements must be loaded via \"shared_preload_libraries\"")));
 
    LWLockAcquire(&pgss->lock.lock, LW_EXCLUSIVE);
    num_entries = hash_get_num_entries(pgss_hash);
 
    stats_reset = GetCurrentTimestamp();
 
    if (userid != 0 && dbid != 0 && queryid != INT64CONST(0))
    {
        /* If all the parameters are available, use the fast path. */
        memset(&key, 0, sizeof(pgssHashKey));
        key.userid = userid;
        key.dbid = dbid;
        key.queryid = queryid;
 
        /*
         * Reset the entry if it exists, starting with the non-top-level
         * entry.
         */
        key.toplevel = false;
        entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
 
        SINGLE_ENTRY_RESET(entry);
 
        /* Also reset the top-level entry if it exists. */
        key.toplevel = true;
        entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
 
        SINGLE_ENTRY_RESET(entry);
    }
    else if (userid != 0 || dbid != 0 || queryid != INT64CONST(0))
    {
        /* Reset entries corresponding to valid parameters. */
        hash_seq_init(&hash_seq, pgss_hash);
        while ((entry = hash_seq_search(&hash_seq)) != NULL)
        {
            if ((!userid || entry->key.userid == userid) &&
                (!dbid || entry->key.dbid == dbid) &&
                (!queryid || entry->key.queryid == queryid))
            {
                SINGLE_ENTRY_RESET(entry);
            }
        }
    }
    else
    {
        /* Reset all entries. */
        hash_seq_init(&hash_seq, pgss_hash);
        while ((entry = hash_seq_search(&hash_seq)) != NULL)
        {
            SINGLE_ENTRY_RESET(entry);
        }
    }
 
    /* All entries are removed? */
    if (num_entries != num_remove)
        goto release_lock;
 
    /*
     * Reset global statistics for pg_stat_statements since all entries are
     * removed.
     */
    SpinLockAcquire(&pgss->mutex);
    pgss->stats.dealloc = 0;
    pgss->stats.stats_reset = stats_reset;
    SpinLockRelease(&pgss->mutex);
 
    /*
     * Write new empty query file, perhaps even creating a new one to recover
     * if the file was missing.
     */
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not create file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        goto done;
    }
 
    /* If ftruncate fails, log it, but it's not a fatal problem */
    if (ftruncate(fileno(qfile), 0) != 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not truncate file \"%s\": %m",
                        PGSS_TEXT_FILE)));
 
    FreeFile(qfile);
 
done:
    pgss->extent = 0;
    /* This counts as a query text garbage collection for our purposes */
    record_gc_qtexts();
 
release_lock:
    LWLockRelease(&pgss->lock.lock);
 
    return stats_reset;
}

References AllocateFile(), pgssHashKey::dbid, pgssGlobalStats::dealloc, ereport, errcode(), errcode_for_file_access(), errmsg, ERROR, pgssSharedState::extent, fb(), FreeFile(), GetCurrentTimestamp(), HASH_FIND, hash_get_num_entries(), hash_search(), hash_seq_init(), hash_seq_search(), INT64CONST, pgssEntry::key, pgssSharedState::lock, LWLockPadded::lock, LOG, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), pgssSharedState::mutex, PG_BINARY_W, pgss, pgss_hash, PGSS_TEXT_FILE, pgssHashKey::queryid, record_gc_qtexts, SINGLE_ENTRY_RESET, SpinLockAcquire(), SpinLockRelease(), pgssSharedState::stats, pgssGlobalStats::stats_reset, and pgssHashKey::userid.

Referenced by pg_stat_statements_reset(), pg_stat_statements_reset_1_11(), and pg_stat_statements_reset_1_7().

gc_qtexts()

static void gc_qtexts ( void  )

static

Definition at line 2474 of file pg_stat_statements.c.

{
    char       *qbuffer;
    Size        qbuffer_size;
    FILE       *qfile = NULL;
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
    Size        extent;
    int         nentries;
 
    /*
     * When called from pgss_store, some other session might have proceeded
     * with garbage collection in the no-lock-held interim of lock strength
     * escalation.  Check once more that this is actually necessary.
     */
    if (!need_gc_qtexts())
        return;
 
    /*
     * Load the old texts file.  If we fail (out of memory, for instance),
     * invalidate query texts.  Hopefully this is rare.  It might seem better
     * to leave things alone on an OOM failure, but the problem is that the
     * file is only going to get bigger; hoping for a future non-OOM result is
     * risky and can easily lead to complete denial of service.
     */
    qbuffer = qtext_load_file(&qbuffer_size);
    if (qbuffer == NULL)
        goto gc_fail;
 
    /*
     * We overwrite the query texts file in place, so as to reduce the risk of
     * an out-of-disk-space failure.  Since the file is guaranteed not to get
     * larger, this should always work on traditional filesystems; though we
     * could still lose on copy-on-write filesystems.
     */
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not write file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        goto gc_fail;
    }
 
    extent = 0;
    nentries = 0;
 
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        int         query_len = entry->query_len;
        char       *qry = qtext_fetch(entry->query_offset,
                                      query_len,
                                      qbuffer,
                                      qbuffer_size);
 
        if (qry == NULL)
        {
            /* Trouble ... drop the text */
            entry->query_offset = 0;
            entry->query_len = -1;
            /* entry will not be counted in mean query length computation */
            continue;
        }
 
        if (fwrite(qry, 1, query_len + 1, qfile) != query_len + 1)
        {
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not write file \"%s\": %m",
                            PGSS_TEXT_FILE)));
            hash_seq_term(&hash_seq);
            goto gc_fail;
        }
 
        entry->query_offset = extent;
        extent += query_len + 1;
        nentries++;
    }
 
    /*
     * Truncate away any now-unused space.  If this fails for some odd reason,
     * we log it, but there's no need to fail.
     */
    if (ftruncate(fileno(qfile), extent) != 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not truncate file \"%s\": %m",
                        PGSS_TEXT_FILE)));
 
    if (FreeFile(qfile))
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not write file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        qfile = NULL;
        goto gc_fail;
    }
 
    elog(DEBUG1, "pgss gc of queries file shrunk size from %zu to %zu",
         pgss->extent, extent);
 
    /* Reset the shared extent pointer */
    pgss->extent = extent;
 
    /*
     * Also update the mean query length, to be sure that need_gc_qtexts()
     * won't still think we have a problem.
     */
    if (nentries > 0)
        pgss->mean_query_len = extent / nentries;
    else
        pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
    pfree(qbuffer);
 
    /*
     * OK, count a garbage collection cycle.  (Note: even though we have
     * exclusive lock on pgss->lock, we must take pgss->mutex for this, since
     * other processes may examine gc_count while holding only the mutex.
     * Also, we have to advance the count *after* we've rewritten the file,
     * else other processes might not realize they read a stale file.)
     */
    record_gc_qtexts();
 
    return;
 
gc_fail:
    /* clean up resources */
    if (qfile)
        FreeFile(qfile);
    if (qbuffer)
        pfree(qbuffer);
 
    /*
     * Since the contents of the external file are now uncertain, mark all
     * hashtable entries as having invalid texts.
     */
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        entry->query_offset = 0;
        entry->query_len = -1;
    }
 
    /*
     * Destroy the query text file and create a new, empty one
     */
    (void) unlink(PGSS_TEXT_FILE);
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not recreate file \"%s\": %m",
                        PGSS_TEXT_FILE)));
    else
        FreeFile(qfile);
 
    /* Reset the shared extent pointer */
    pgss->extent = 0;
 
    /* Reset mean_query_len to match the new state */
    pgss->mean_query_len = ASSUMED_LENGTH_INIT;
 
    /*
     * Bump the GC count even though we failed.
     *
     * This is needed to make concurrent readers of file without any lock on
     * pgss->lock notice existence of new version of file.  Once readers
     * subsequently observe a change in GC count with pgss->lock held, that
     * forces a safe reopen of file.  Writers also require that we bump here,
     * of course.  (As required by locking protocol, readers and writers don't
     * trust earlier file contents until gc_count is found unchanged after
     * pgss->lock acquired in shared or exclusive mode respectively.)
     */
    record_gc_qtexts();
}

References AllocateFile(), ASSUMED_LENGTH_INIT, DEBUG1, elog, ereport, errcode_for_file_access(), errmsg, pgssSharedState::extent, fb(), FreeFile(), hash_seq_init(), hash_seq_search(), hash_seq_term(), LOG, pgssSharedState::mean_query_len, need_gc_qtexts(), pfree(), PG_BINARY_W, pgss, pgss_hash, PGSS_TEXT_FILE, qtext_fetch(), qtext_load_file(), pgssEntry::query_len, pgssEntry::query_offset, and record_gc_qtexts.

Referenced by pgss_store().

generate_normalized_query()

static char * generate_normalized_query ( const JumbleState *  jstate, const char *  query, int  query_loc, int *  query_len_p  )

static

Definition at line 2811 of file pg_stat_statements.c.

{
    char       *norm_query;
    int         query_len = *query_len_p;
    int         norm_query_buflen,  /* Space allowed for norm_query */
                len_to_wrt,     /* Length (in bytes) to write */
                quer_loc = 0,   /* Source query byte location */
                n_quer_loc = 0, /* Normalized query byte location */
                last_off = 0,   /* Offset from start for previous tok */
                last_tok_len = 0;   /* Length (in bytes) of that tok */
    int         num_constants_replaced = 0;
    LocationLen *locs = NULL;
 
    /*
     * Determine constants' lengths (core system only gives us locations), and
     * return a sorted copy of jstate's LocationLen data with lengths filled
     * in.
     */
    locs = ComputeConstantLengths(jstate, query, query_loc);
 
    /*
     * Allow for $n symbols to be longer than the constants they replace.
     * Constants must take at least one byte in text form, while a $n symbol
     * certainly isn't more than 11 bytes, even if n reaches INT_MAX.  We
     * could refine that limit based on the max value of n for the current
     * query, but it hardly seems worth any extra effort to do so.
     */
    norm_query_buflen = query_len + jstate->clocations_count * 10;
 
    /* Allocate result buffer */
    norm_query = palloc(norm_query_buflen + 1);
 
    for (int i = 0; i < jstate->clocations_count; i++)
    {
        int         off,        /* Offset from start for cur tok */
                    tok_len;    /* Length (in bytes) of that tok */
 
        /*
         * If we have an external param at this location, but no lists are
         * being squashed across the query, then we skip here; this will make
         * us print the characters found in the original query that represent
         * the parameter in the next iteration (or after the loop is done),
         * which is a bit odd but seems to work okay in most cases.
         */
        if (locs[i].extern_param && !jstate->has_squashed_lists)
            continue;
 
        off = locs[i].location;
 
        /* Adjust recorded location if we're dealing with partial string */
        off -= query_loc;
 
        tok_len = locs[i].length;
 
        if (tok_len < 0)
            continue;           /* ignore any duplicates */
 
        /* Copy next chunk (what precedes the next constant) */
        len_to_wrt = off - last_off;
        len_to_wrt -= last_tok_len;
        Assert(len_to_wrt >= 0);
        memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
        n_quer_loc += len_to_wrt;
 
        /*
         * And insert a param symbol in place of the constant token; and, if
         * we have a squashable list, insert a placeholder comment starting
         * from the list's second value.
         */
        n_quer_loc += sprintf(norm_query + n_quer_loc, "$%d%s",
                              num_constants_replaced + 1 + jstate->highest_extern_param_id,
                              locs[i].squashed ? " /*, ... */" : "");
        num_constants_replaced++;
 
        /* move forward */
        quer_loc = off + tok_len;
        last_off = off;
        last_tok_len = tok_len;
    }
 
    /* Clean up, if needed */
    if (locs)
        pfree(locs);
 
    /*
     * We've copied up until the last ignorable constant.  Copy over the
     * remaining bytes of the original query string.
     */
    len_to_wrt = query_len - quer_loc;
 
    Assert(len_to_wrt >= 0);
    memcpy(norm_query + n_quer_loc, query + quer_loc, len_to_wrt);
    n_quer_loc += len_to_wrt;
 
    Assert(n_quer_loc <= norm_query_buflen);
    norm_query[n_quer_loc] = '\0';
 
    *query_len_p = n_quer_loc;
    return norm_query;
}

References Assert, ComputeConstantLengths(), fb(), i, memcpy(), palloc(), pfree(), and sprintf.

Referenced by pgss_store().

need_gc_qtexts()

static bool need_gc_qtexts ( void  )

static

Definition at line 2425 of file pg_stat_statements.c.

{
    Size        extent;
 
    /* Read shared extent pointer */
    SpinLockAcquire(&pgss->mutex);
    extent = pgss->extent;
    SpinLockRelease(&pgss->mutex);
 
    /*
     * Don't proceed if file does not exceed 512 bytes per possible entry.
     *
     * Here and in the next test, 32-bit machines have overflow hazards if
     * pgss_max and/or mean_query_len are large.  Force the multiplications
     * and comparisons to be done in uint64 arithmetic to forestall trouble.
     */
    if ((uint64) extent < (uint64) 512 * pgss_max)
        return false;
 
    /*
     * Don't proceed if file is less than about 50% bloat.  Nothing can or
     * should be done in the event of unusually large query texts accounting
     * for file's large size.  We go to the trouble of maintaining the mean
     * query length in order to prevent garbage collection from thrashing
     * uselessly.
     */
    if ((uint64) extent < (uint64) pgss->mean_query_len * pgss_max * 2)
        return false;
 
    return true;
}

References pgssSharedState::extent, pgssSharedState::mean_query_len, pgssSharedState::mutex, pgss, pgss_max, SpinLockAcquire(), and SpinLockRelease().

Referenced by gc_qtexts(), and pgss_store().

PG_FUNCTION_INFO_V1() [1/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements

)

PG_FUNCTION_INFO_V1() [2/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_10

)

PG_FUNCTION_INFO_V1() [3/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_11

)

PG_FUNCTION_INFO_V1() [4/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_12

)

PG_FUNCTION_INFO_V1() [5/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_13

)

PG_FUNCTION_INFO_V1() [6/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_2

)

PG_FUNCTION_INFO_V1() [7/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_3

)

PG_FUNCTION_INFO_V1() [8/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_8

)

PG_FUNCTION_INFO_V1() [9/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_1_9

)

PG_FUNCTION_INFO_V1() [10/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_info

)

PG_FUNCTION_INFO_V1() [11/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_reset

)

PG_FUNCTION_INFO_V1() [12/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_reset_1_11

)

PG_FUNCTION_INFO_V1() [13/13]

PG_FUNCTION_INFO_V1

(

pg_stat_statements_reset_1_7

)

PG_MODULE_MAGIC_EXT()

PG_MODULE_MAGIC_EXT	(	.	name = "pg_stat_statements",
		.	version = PG_VERSION
	)

pg_stat_statements()

Datum pg_stat_statements

(

PG_FUNCTION_ARGS

)

Definition at line 1656 of file pg_stat_statements.c.

{
    /* If it's really API 1.1, we'll figure that out below */
    pg_stat_statements_internal(fcinfo, PGSS_V1_0, true);
 
    return (Datum) 0;
}

References pg_stat_statements_internal(), and PGSS_V1_0.

pg_stat_statements_1_10()

Datum pg_stat_statements_1_10

(

PG_FUNCTION_ARGS

)

Definition at line 1602 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_10, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_10.

pg_stat_statements_1_11()

Datum pg_stat_statements_1_11

(

PG_FUNCTION_ARGS

)

Definition at line 1592 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_11, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_11.

pg_stat_statements_1_12()

Datum pg_stat_statements_1_12

(

PG_FUNCTION_ARGS

)

Definition at line 1582 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_12, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_12.

pg_stat_statements_1_13()

Datum pg_stat_statements_1_13

(

PG_FUNCTION_ARGS

)

Definition at line 1572 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_13, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_13.

pg_stat_statements_1_2()

Datum pg_stat_statements_1_2

(

PG_FUNCTION_ARGS

)

Definition at line 1642 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_2, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_2.

pg_stat_statements_1_3()

Datum pg_stat_statements_1_3

(

PG_FUNCTION_ARGS

)

Definition at line 1632 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_3, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_3.

pg_stat_statements_1_8()

Datum pg_stat_statements_1_8

(

PG_FUNCTION_ARGS

)

Definition at line 1622 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_8, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_8.

pg_stat_statements_1_9()

Datum pg_stat_statements_1_9

(

PG_FUNCTION_ARGS

)

Definition at line 1612 of file pg_stat_statements.c.

{
    bool        showtext = PG_GETARG_BOOL(0);
 
    pg_stat_statements_internal(fcinfo, PGSS_V1_9, showtext);
 
    return (Datum) 0;
}

References fb(), PG_GETARG_BOOL, pg_stat_statements_internal(), and PGSS_V1_9.

pg_stat_statements_info()

Datum pg_stat_statements_info

(

PG_FUNCTION_ARGS

)

Definition at line 2035 of file pg_stat_statements.c.

{
    pgssGlobalStats stats;
    TupleDesc   tupdesc;
    Datum       values[PG_STAT_STATEMENTS_INFO_COLS] = {0};
    bool        nulls[PG_STAT_STATEMENTS_INFO_COLS] = {0};
 
    if (!pgss || !pgss_hash)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_stat_statements must be loaded via \"shared_preload_libraries\"")));
 
    /* Build a tuple descriptor for our result type */
    if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
        elog(ERROR, "return type must be a row type");
 
    /* Read global statistics for pg_stat_statements */
    SpinLockAcquire(&pgss->mutex);
    stats = pgss->stats;
    SpinLockRelease(&pgss->mutex);
 
    values[0] = Int64GetDatum(stats.dealloc);
    values[1] = TimestampTzGetDatum(stats.stats_reset);
 
    PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
}

References pgssGlobalStats::dealloc, elog, ereport, errcode(), errmsg, ERROR, fb(), get_call_result_type(), heap_form_tuple(), HeapTupleGetDatum(), Int64GetDatum(), pgssSharedState::mutex, PG_RETURN_DATUM, PG_STAT_STATEMENTS_INFO_COLS, pgss, pgss_hash, SpinLockAcquire(), SpinLockRelease(), pgssSharedState::stats, pgssGlobalStats::stats_reset, TimestampTzGetDatum(), TYPEFUNC_COMPOSITE, and values.

pg_stat_statements_internal()

static void pg_stat_statements_internal ( FunctionCallInfo  fcinfo, pgssVersion  api_version, bool  showtext  )

static

Definition at line 1666 of file pg_stat_statements.c.

{
    ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
    Oid         userid = GetUserId();
    bool        is_allowed_role = false;
    char       *qbuffer = NULL;
    Size        qbuffer_size = 0;
    Size        extent = 0;
    int         gc_count = 0;
    HASH_SEQ_STATUS hash_seq;
    pgssEntry  *entry;
 
    /*
     * Superusers or roles with the privileges of pg_read_all_stats members
     * are allowed
     */
    is_allowed_role = has_privs_of_role(userid, ROLE_PG_READ_ALL_STATS);
 
    /* hash table must exist already */
    if (!pgss || !pgss_hash)
        ereport(ERROR,
                (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
                 errmsg("pg_stat_statements must be loaded via \"shared_preload_libraries\"")));
 
    InitMaterializedSRF(fcinfo, 0);
 
    /*
     * Check we have the expected number of output arguments.  Aside from
     * being a good safety check, we need a kluge here to detect API version
     * 1.1, which was wedged into the code in an ill-considered way.
     */
    switch (rsinfo->setDesc->natts)
    {
        case PG_STAT_STATEMENTS_COLS_V1_0:
            if (api_version != PGSS_V1_0)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_1:
            /* pg_stat_statements() should have told us 1.0 */
            if (api_version != PGSS_V1_0)
                elog(ERROR, "incorrect number of output arguments");
            api_version = PGSS_V1_1;
            break;
        case PG_STAT_STATEMENTS_COLS_V1_2:
            if (api_version != PGSS_V1_2)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_3:
            if (api_version != PGSS_V1_3)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_8:
            if (api_version != PGSS_V1_8)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_9:
            if (api_version != PGSS_V1_9)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_10:
            if (api_version != PGSS_V1_10)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_11:
            if (api_version != PGSS_V1_11)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_12:
            if (api_version != PGSS_V1_12)
                elog(ERROR, "incorrect number of output arguments");
            break;
        case PG_STAT_STATEMENTS_COLS_V1_13:
            if (api_version != PGSS_V1_13)
                elog(ERROR, "incorrect number of output arguments");
            break;
        default:
            elog(ERROR, "incorrect number of output arguments");
    }
 
    /*
     * We'd like to load the query text file (if needed) while not holding any
     * lock on pgss->lock.  In the worst case we'll have to do this again
     * after we have the lock, but it's unlikely enough to make this a win
     * despite occasional duplicated work.  We need to reload if anybody
     * writes to the file (either a retail qtext_store(), or a garbage
     * collection) between this point and where we've gotten shared lock.  If
     * a qtext_store is actually in progress when we look, we might as well
     * skip the speculative load entirely.
     */
    if (showtext)
    {
        int         n_writers;
 
        /* Take the mutex so we can examine variables */
        SpinLockAcquire(&pgss->mutex);
        extent = pgss->extent;
        n_writers = pgss->n_writers;
        gc_count = pgss->gc_count;
        SpinLockRelease(&pgss->mutex);
 
        /* No point in loading file now if there are active writers */
        if (n_writers == 0)
            qbuffer = qtext_load_file(&qbuffer_size);
    }
 
    /*
     * Get shared lock, load or reload the query text file if we must, and
     * iterate over the hashtable entries.
     *
     * With a large hash table, we might be holding the lock rather longer
     * than one could wish.  However, this only blocks creation of new hash
     * table entries, and the larger the hash table the less likely that is to
     * be needed.  So we can hope this is okay.  Perhaps someday we'll decide
     * we need to partition the hash table to limit the time spent holding any
     * one lock.
     */
    LWLockAcquire(&pgss->lock.lock, LW_SHARED);
 
    if (showtext)
    {
        /*
         * Here it is safe to examine extent and gc_count without taking the
         * mutex.  Note that although other processes might change
         * pgss->extent just after we look at it, the strings they then write
         * into the file cannot yet be referenced in the hashtable, so we
         * don't care whether we see them or not.
         *
         * If qtext_load_file fails, we just press on; we'll return NULL for
         * every query text.
         */
        if (qbuffer == NULL ||
            pgss->extent != extent ||
            pgss->gc_count != gc_count)
        {
            if (qbuffer)
                pfree(qbuffer);
            qbuffer = qtext_load_file(&qbuffer_size);
        }
    }
 
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        Datum       values[PG_STAT_STATEMENTS_COLS];
        bool        nulls[PG_STAT_STATEMENTS_COLS];
        int         i = 0;
        Counters    tmp;
        double      stddev;
        int64       queryid = entry->key.queryid;
        TimestampTz stats_since;
        TimestampTz minmax_stats_since;
 
        memset(values, 0, sizeof(values));
        memset(nulls, 0, sizeof(nulls));
 
        values[i++] = ObjectIdGetDatum(entry->key.userid);
        values[i++] = ObjectIdGetDatum(entry->key.dbid);
        if (api_version >= PGSS_V1_9)
            values[i++] = BoolGetDatum(entry->key.toplevel);
 
        if (is_allowed_role || entry->key.userid == userid)
        {
            if (api_version >= PGSS_V1_2)
                values[i++] = Int64GetDatumFast(queryid);
 
            if (showtext)
            {
                char       *qstr = qtext_fetch(entry->query_offset,
                                               entry->query_len,
                                               qbuffer,
                                               qbuffer_size);
 
                if (qstr)
                {
                    char       *enc;
 
                    enc = pg_any_to_server(qstr,
                                           entry->query_len,
                                           entry->encoding);
 
                    values[i++] = CStringGetTextDatum(enc);
 
                    if (enc != qstr)
                        pfree(enc);
                }
                else
                {
                    /* Just return a null if we fail to find the text */
                    nulls[i++] = true;
                }
            }
            else
            {
                /* Query text not requested */
                nulls[i++] = true;
            }
        }
        else
        {
            /* Don't show queryid */
            if (api_version >= PGSS_V1_2)
                nulls[i++] = true;
 
            /*
             * Don't show query text, but hint as to the reason for not doing
             * so if it was requested
             */
            if (showtext)
                values[i++] = CStringGetTextDatum("<insufficient privilege>");
            else
                nulls[i++] = true;
        }
 
        /* copy counters to a local variable to keep locking time short */
        SpinLockAcquire(&entry->mutex);
        tmp = entry->counters;
        SpinLockRelease(&entry->mutex);
 
        /*
         * The spinlock is not required when reading these two as they are
         * always updated when holding pgss->lock exclusively.
         */
        stats_since = entry->stats_since;
        minmax_stats_since = entry->minmax_stats_since;
 
        /* Skip entry if unexecuted (ie, it's a pending "sticky" entry) */
        if (IS_STICKY(tmp))
            continue;
 
        /* Note that we rely on PGSS_PLAN being 0 and PGSS_EXEC being 1. */
        for (int kind = 0; kind < PGSS_NUMKIND; kind++)
        {
            if (kind == PGSS_EXEC || api_version >= PGSS_V1_8)
            {
                values[i++] = Int64GetDatumFast(tmp.calls[kind]);
                values[i++] = Float8GetDatumFast(tmp.total_time[kind]);
            }
 
            if ((kind == PGSS_EXEC && api_version >= PGSS_V1_3) ||
                api_version >= PGSS_V1_8)
            {
                values[i++] = Float8GetDatumFast(tmp.min_time[kind]);
                values[i++] = Float8GetDatumFast(tmp.max_time[kind]);
                values[i++] = Float8GetDatumFast(tmp.mean_time[kind]);
 
                /*
                 * Note we are calculating the population variance here, not
                 * the sample variance, as we have data for the whole
                 * population, so Bessel's correction is not used, and we
                 * don't divide by tmp.calls - 1.
                 */
                if (tmp.calls[kind] > 1)
                    stddev = sqrt(tmp.sum_var_time[kind] / tmp.calls[kind]);
                else
                    stddev = 0.0;
                values[i++] = Float8GetDatumFast(stddev);
            }
        }
        values[i++] = Int64GetDatumFast(tmp.rows);
        values[i++] = Int64GetDatumFast(tmp.shared_blks_hit);
        values[i++] = Int64GetDatumFast(tmp.shared_blks_read);
        if (api_version >= PGSS_V1_1)
            values[i++] = Int64GetDatumFast(tmp.shared_blks_dirtied);
        values[i++] = Int64GetDatumFast(tmp.shared_blks_written);
        values[i++] = Int64GetDatumFast(tmp.local_blks_hit);
        values[i++] = Int64GetDatumFast(tmp.local_blks_read);
        if (api_version >= PGSS_V1_1)
            values[i++] = Int64GetDatumFast(tmp.local_blks_dirtied);
        values[i++] = Int64GetDatumFast(tmp.local_blks_written);
        values[i++] = Int64GetDatumFast(tmp.temp_blks_read);
        values[i++] = Int64GetDatumFast(tmp.temp_blks_written);
        if (api_version >= PGSS_V1_1)
        {
            values[i++] = Float8GetDatumFast(tmp.shared_blk_read_time);
            values[i++] = Float8GetDatumFast(tmp.shared_blk_write_time);
        }
        if (api_version >= PGSS_V1_11)
        {
            values[i++] = Float8GetDatumFast(tmp.local_blk_read_time);
            values[i++] = Float8GetDatumFast(tmp.local_blk_write_time);
        }
        if (api_version >= PGSS_V1_10)
        {
            values[i++] = Float8GetDatumFast(tmp.temp_blk_read_time);
            values[i++] = Float8GetDatumFast(tmp.temp_blk_write_time);
        }
        if (api_version >= PGSS_V1_8)
        {
            char        buf[256];
            Datum       wal_bytes;
 
            values[i++] = Int64GetDatumFast(tmp.wal_records);
            values[i++] = Int64GetDatumFast(tmp.wal_fpi);
 
            snprintf(buf, sizeof buf, UINT64_FORMAT, tmp.wal_bytes);
 
            /* Convert to numeric. */
            wal_bytes = DirectFunctionCall3(numeric_in,
                                            CStringGetDatum(buf),
                                            ObjectIdGetDatum(0),
                                            Int32GetDatum(-1));
            values[i++] = wal_bytes;
        }
        if (api_version >= PGSS_V1_12)
        {
            values[i++] = Int64GetDatumFast(tmp.wal_buffers_full);
        }
        if (api_version >= PGSS_V1_10)
        {
            values[i++] = Int64GetDatumFast(tmp.jit_functions);
            values[i++] = Float8GetDatumFast(tmp.jit_generation_time);
            values[i++] = Int64GetDatumFast(tmp.jit_inlining_count);
            values[i++] = Float8GetDatumFast(tmp.jit_inlining_time);
            values[i++] = Int64GetDatumFast(tmp.jit_optimization_count);
            values[i++] = Float8GetDatumFast(tmp.jit_optimization_time);
            values[i++] = Int64GetDatumFast(tmp.jit_emission_count);
            values[i++] = Float8GetDatumFast(tmp.jit_emission_time);
        }
        if (api_version >= PGSS_V1_11)
        {
            values[i++] = Int64GetDatumFast(tmp.jit_deform_count);
            values[i++] = Float8GetDatumFast(tmp.jit_deform_time);
        }
        if (api_version >= PGSS_V1_12)
        {
            values[i++] = Int64GetDatumFast(tmp.parallel_workers_to_launch);
            values[i++] = Int64GetDatumFast(tmp.parallel_workers_launched);
        }
        if (api_version >= PGSS_V1_13)
        {
            values[i++] = Int64GetDatumFast(tmp.generic_plan_calls);
            values[i++] = Int64GetDatumFast(tmp.custom_plan_calls);
        }
        if (api_version >= PGSS_V1_11)
        {
            values[i++] = TimestampTzGetDatum(stats_since);
            values[i++] = TimestampTzGetDatum(minmax_stats_since);
        }
 
        Assert(i == (api_version == PGSS_V1_0 ? PG_STAT_STATEMENTS_COLS_V1_0 :
                     api_version == PGSS_V1_1 ? PG_STAT_STATEMENTS_COLS_V1_1 :
                     api_version == PGSS_V1_2 ? PG_STAT_STATEMENTS_COLS_V1_2 :
                     api_version == PGSS_V1_3 ? PG_STAT_STATEMENTS_COLS_V1_3 :
                     api_version == PGSS_V1_8 ? PG_STAT_STATEMENTS_COLS_V1_8 :
                     api_version == PGSS_V1_9 ? PG_STAT_STATEMENTS_COLS_V1_9 :
                     api_version == PGSS_V1_10 ? PG_STAT_STATEMENTS_COLS_V1_10 :
                     api_version == PGSS_V1_11 ? PG_STAT_STATEMENTS_COLS_V1_11 :
                     api_version == PGSS_V1_12 ? PG_STAT_STATEMENTS_COLS_V1_12 :
                     api_version == PGSS_V1_13 ? PG_STAT_STATEMENTS_COLS_V1_13 :
                     -1 /* fail if you forget to update this assert */ ));
 
        tuplestore_putvalues(rsinfo->setResult, rsinfo->setDesc, values, nulls);
    }
 
    LWLockRelease(&pgss->lock.lock);
 
    if (qbuffer)
        pfree(qbuffer);
}

References Assert, BoolGetDatum(), buf, Counters::calls, pgssEntry::counters, CStringGetDatum(), CStringGetTextDatum, Counters::custom_plan_calls, pgssHashKey::dbid, DirectFunctionCall3, elog, enc, pgssEntry::encoding, ereport, errcode(), errmsg, ERROR, pgssSharedState::extent, fb(), Float8GetDatumFast, pgssSharedState::gc_count, Counters::generic_plan_calls, GetUserId(), has_privs_of_role(), hash_seq_init(), hash_seq_search(), i, InitMaterializedSRF(), Int32GetDatum(), Int64GetDatumFast, IS_STICKY, Counters::jit_deform_count, Counters::jit_deform_time, Counters::jit_emission_count, Counters::jit_emission_time, Counters::jit_functions, Counters::jit_generation_time, Counters::jit_inlining_count, Counters::jit_inlining_time, Counters::jit_optimization_count, Counters::jit_optimization_time, pgssEntry::key, Counters::local_blk_read_time, Counters::local_blk_write_time, Counters::local_blks_dirtied, Counters::local_blks_hit, Counters::local_blks_read, Counters::local_blks_written, pgssSharedState::lock, LWLockPadded::lock, LW_SHARED, LWLockAcquire(), LWLockRelease(), Counters::max_time, Counters::mean_time, Counters::min_time, pgssEntry::minmax_stats_since, pgssEntry::mutex, pgssSharedState::mutex, pgssSharedState::n_writers, numeric_in(), ObjectIdGetDatum(), Counters::parallel_workers_launched, Counters::parallel_workers_to_launch, pfree(), pg_any_to_server(), PG_STAT_STATEMENTS_COLS, PG_STAT_STATEMENTS_COLS_V1_0, PG_STAT_STATEMENTS_COLS_V1_1, PG_STAT_STATEMENTS_COLS_V1_10, PG_STAT_STATEMENTS_COLS_V1_11, PG_STAT_STATEMENTS_COLS_V1_12, PG_STAT_STATEMENTS_COLS_V1_13, PG_STAT_STATEMENTS_COLS_V1_2, PG_STAT_STATEMENTS_COLS_V1_3, PG_STAT_STATEMENTS_COLS_V1_8, PG_STAT_STATEMENTS_COLS_V1_9, pgss, PGSS_EXEC, pgss_hash, PGSS_NUMKIND, PGSS_V1_0, PGSS_V1_1, PGSS_V1_10, PGSS_V1_11, PGSS_V1_12, PGSS_V1_13, PGSS_V1_2, PGSS_V1_3, PGSS_V1_8, PGSS_V1_9, qtext_fetch(), qtext_load_file(), pgssEntry::query_len, pgssEntry::query_offset, pgssHashKey::queryid, FunctionCallInfoBaseData::resultinfo, Counters::rows, Counters::shared_blk_read_time, Counters::shared_blk_write_time, Counters::shared_blks_dirtied, Counters::shared_blks_hit, Counters::shared_blks_read, Counters::shared_blks_written, snprintf, SpinLockAcquire(), SpinLockRelease(), pgssEntry::stats_since, Counters::sum_var_time, Counters::temp_blk_read_time, Counters::temp_blk_write_time, Counters::temp_blks_read, Counters::temp_blks_written, TimestampTzGetDatum(), pgssHashKey::toplevel, Counters::total_time, tuplestore_putvalues(), UINT64_FORMAT, pgssHashKey::userid, values, Counters::wal_buffers_full, Counters::wal_bytes, Counters::wal_fpi, and Counters::wal_records.

Referenced by pg_stat_statements(), pg_stat_statements_1_10(), pg_stat_statements_1_11(), pg_stat_statements_1_12(), pg_stat_statements_1_13(), pg_stat_statements_1_2(), pg_stat_statements_1_3(), pg_stat_statements_1_8(), and pg_stat_statements_1_9().

pg_stat_statements_reset()

Datum pg_stat_statements_reset

(

PG_FUNCTION_ARGS

)

Definition at line 1541 of file pg_stat_statements.c.

{
    entry_reset(0, 0, 0, false);
 
    PG_RETURN_VOID();
}

References entry_reset(), and PG_RETURN_VOID.

pg_stat_statements_reset_1_11()

Datum pg_stat_statements_reset_1_11

(

PG_FUNCTION_ARGS

)

Definition at line 1522 of file pg_stat_statements.c.

{
    Oid         userid;
    Oid         dbid;
    int64       queryid;
    bool        minmax_only;
 
    userid = PG_GETARG_OID(0);
    dbid = PG_GETARG_OID(1);
    queryid = PG_GETARG_INT64(2);
    minmax_only = PG_GETARG_BOOL(3);
 
    PG_RETURN_TIMESTAMPTZ(entry_reset(userid, dbid, queryid, minmax_only));
}

References entry_reset(), fb(), PG_GETARG_BOOL, PG_GETARG_INT64, PG_GETARG_OID, and PG_RETURN_TIMESTAMPTZ.

pg_stat_statements_reset_1_7()

Datum pg_stat_statements_reset_1_7

(

PG_FUNCTION_ARGS

)

Definition at line 1506 of file pg_stat_statements.c.

{
    Oid         userid;
    Oid         dbid;
    int64       queryid;
 
    userid = PG_GETARG_OID(0);
    dbid = PG_GETARG_OID(1);
    queryid = PG_GETARG_INT64(2);
 
    entry_reset(userid, dbid, queryid, false);
 
    PG_RETURN_VOID();
}

References entry_reset(), PG_GETARG_INT64, PG_GETARG_OID, and PG_RETURN_VOID.

pgss_ExecutorEnd()

static void pgss_ExecutorEnd ( QueryDesc *  queryDesc )

static

Definition at line 1059 of file pg_stat_statements.c.

{
    int64       queryId = queryDesc->plannedstmt->queryId;
 
    if (queryId != INT64CONST(0) && queryDesc->query_instr &&
        pgss_enabled(nesting_level))
    {
        pgss_store(queryDesc->sourceText,
                   queryId,
                   queryDesc->plannedstmt->stmt_location,
                   queryDesc->plannedstmt->stmt_len,
                   PGSS_EXEC,
                   INSTR_TIME_GET_MILLISEC(queryDesc->query_instr->total),
                   queryDesc->estate->es_total_processed,
                   &queryDesc->query_instr->bufusage,
                   &queryDesc->query_instr->walusage,
                   queryDesc->estate->es_jit ? &queryDesc->estate->es_jit->instr : NULL,
                   NULL,
                   queryDesc->estate->es_parallel_workers_to_launch,
                   queryDesc->estate->es_parallel_workers_launched,
                   queryDesc->plannedstmt->planOrigin);
    }
 
    if (prev_ExecutorEnd)
        prev_ExecutorEnd(queryDesc);
    else
        standard_ExecutorEnd(queryDesc);
}

References Instrumentation::bufusage, EState::es_jit, EState::es_parallel_workers_launched, EState::es_parallel_workers_to_launch, EState::es_total_processed, QueryDesc::estate, fb(), JitContext::instr, INSTR_TIME_GET_MILLISEC, INT64CONST, nesting_level, pgss_enabled, PGSS_EXEC, pgss_store(), QueryDesc::plannedstmt, PlannedStmt::planOrigin, prev_ExecutorEnd, QueryDesc::query_instr, PlannedStmt::queryId, QueryDesc::sourceText, standard_ExecutorEnd(), PlannedStmt::stmt_len, PlannedStmt::stmt_location, Instrumentation::total, and Instrumentation::walusage.

Referenced by _PG_init().

pgss_ExecutorFinish()

static void pgss_ExecutorFinish ( QueryDesc *  queryDesc )

static

Definition at line 1038 of file pg_stat_statements.c.

{
    nesting_level++;
    PG_TRY();
    {
        if (prev_ExecutorFinish)
            prev_ExecutorFinish(queryDesc);
        else
            standard_ExecutorFinish(queryDesc);
    }
    PG_FINALLY();
    {
        nesting_level--;
    }
    PG_END_TRY();
}

References nesting_level, PG_END_TRY, PG_FINALLY, PG_TRY, prev_ExecutorFinish, and standard_ExecutorFinish().

Referenced by _PG_init().

pgss_ExecutorRun()

static void pgss_ExecutorRun ( QueryDesc *  queryDesc, ScanDirection  direction, uint64  count  )

static

Definition at line 1017 of file pg_stat_statements.c.

{
    nesting_level++;
    PG_TRY();
    {
        if (prev_ExecutorRun)
            prev_ExecutorRun(queryDesc, direction, count);
        else
            standard_ExecutorRun(queryDesc, direction, count);
    }
    PG_FINALLY();
    {
        nesting_level--;
    }
    PG_END_TRY();
}

References nesting_level, PG_END_TRY, PG_FINALLY, PG_TRY, prev_ExecutorRun, and standard_ExecutorRun().

Referenced by _PG_init().

pgss_ExecutorStart()

static void pgss_ExecutorStart ( QueryDesc *  queryDesc, int  eflags  )

static

Definition at line 994 of file pg_stat_statements.c.

{
    /*
     * If query has queryId zero, don't track it.  This prevents double
     * counting of optimizable statements that are directly contained in
     * utility statements.
     */
    if (pgss_enabled(nesting_level) && queryDesc->plannedstmt->queryId != INT64CONST(0))
    {
        /* Request all summary instrumentation, i.e. timing, buffers and WAL */
        queryDesc->query_instr_options |= INSTRUMENT_ALL;
    }
 
    if (prev_ExecutorStart)
        prev_ExecutorStart(queryDesc, eflags);
    else
        standard_ExecutorStart(queryDesc, eflags);
}

References INSTRUMENT_ALL, INT64CONST, nesting_level, pgss_enabled, QueryDesc::plannedstmt, prev_ExecutorStart, QueryDesc::query_instr_options, PlannedStmt::queryId, and standard_ExecutorStart().

Referenced by _PG_init().

pgss_planner()

static PlannedStmt * pgss_planner ( Query *  parse, const char *  query_string, int  cursorOptions, ParamListInfo  boundParams, ExplainState *  es  )

static

Definition at line 887 of file pg_stat_statements.c.

{
    PlannedStmt *result;
 
    /*
     * We can't process the query if no query_string is provided, as
     * pgss_store needs it.  We also ignore query without queryid, as it would
     * be treated as a utility statement, which may not be the case.
     */
    if (pgss_enabled(nesting_level)
        && pgss_track_planning && query_string
        && parse->queryId != INT64CONST(0))
    {
        instr_time  start;
        instr_time  duration;
        BufferUsage bufusage_start,
                    bufusage;
        WalUsage    walusage_start,
                    walusage;
 
        /* We need to track buffer usage as the planner can access them. */
        bufusage_start = pgBufferUsage;
 
        /*
         * Similarly the planner could write some WAL records in some cases
         * (e.g. setting a hint bit with those being WAL-logged)
         */
        walusage_start = pgWalUsage;
        INSTR_TIME_SET_CURRENT(start);
 
        nesting_level++;
        PG_TRY();
        {
            if (prev_planner_hook)
                result = prev_planner_hook(parse, query_string, cursorOptions,
                                           boundParams, es);
            else
                result = standard_planner(parse, query_string, cursorOptions,
                                          boundParams, es);
        }
        PG_FINALLY();
        {
            nesting_level--;
        }
        PG_END_TRY();
 
        INSTR_TIME_SET_CURRENT(duration);
        INSTR_TIME_SUBTRACT(duration, start);
 
        /* calc differences of buffer counters. */
        memset(&bufusage, 0, sizeof(BufferUsage));
        BufferUsageAccumDiff(&bufusage, &pgBufferUsage, &bufusage_start);
 
        /* calc differences of WAL counters. */
        memset(&walusage, 0, sizeof(WalUsage));
        WalUsageAccumDiff(&walusage, &pgWalUsage, &walusage_start);
 
        pgss_store(query_string,
                   parse->queryId,
                   parse->stmt_location,
                   parse->stmt_len,
                   PGSS_PLAN,
                   INSTR_TIME_GET_MILLISEC(duration),
                   0,
                   &bufusage,
                   &walusage,
                   NULL,
                   NULL,
                   0,
                   0,
                   result->planOrigin);
    }
    else
    {
        /*
         * Even though we're not tracking plan time for this statement, we
         * must still increment the nesting level, to ensure that functions
         * evaluated during planning are not seen as top-level calls.
         */
        nesting_level++;
        PG_TRY();
        {
            if (prev_planner_hook)
                result = prev_planner_hook(parse, query_string, cursorOptions,
                                           boundParams, es);
            else
                result = standard_planner(parse, query_string, cursorOptions,
                                          boundParams, es);
        }
        PG_FINALLY();
        {
            nesting_level--;
        }
        PG_END_TRY();
    }
 
    return result;
}

References BufferUsageAccumDiff(), duration, fb(), INSTR_TIME_GET_MILLISEC, INSTR_TIME_SET_CURRENT, INSTR_TIME_SUBTRACT, INT64CONST, nesting_level, parse(), PG_END_TRY, PG_FINALLY, PG_TRY, pgBufferUsage, pgss_enabled, PGSS_PLAN, pgss_store(), pgss_track_planning, pgWalUsage, prev_planner_hook, result, standard_planner(), start, and WalUsageAccumDiff().

Referenced by _PG_init().

pgss_post_parse_analyze()

static void pgss_post_parse_analyze ( ParseState *  pstate, Query *  query, const JumbleState *  jstate  )

static

Definition at line 834 of file pg_stat_statements.c.

{
    if (prev_post_parse_analyze_hook)
        prev_post_parse_analyze_hook(pstate, query, jstate);
 
    /* Safety check... */
    if (!pgss || !pgss_hash || !pgss_enabled(nesting_level))
        return;
 
    /*
     * If it's EXECUTE, clear the queryId so that stats will accumulate for
     * the underlying PREPARE.  But don't do this if we're not tracking
     * utility statements, to avoid messing up another extension that might be
     * tracking them.
     */
    if (query->utilityStmt)
    {
        if (pgss_track_utility && IsA(query->utilityStmt, ExecuteStmt))
        {
            query->queryId = INT64CONST(0);
            return;
        }
    }
 
    /*
     * If query jumbling were able to identify any ignorable constants, we
     * immediately create a hash table entry for the query, so that we can
     * record the normalized form of the query string.  If there were no such
     * constants, the normalized string would be the same as the query text
     * anyway, so there's no need for an early entry.
     */
    if (jstate && jstate->clocations_count > 0)
        pgss_store(pstate->p_sourcetext,
                   query->queryId,
                   query->stmt_location,
                   query->stmt_len,
                   PGSS_INVALID,
                   0,
                   0,
                   NULL,
                   NULL,
                   NULL,
                   jstate,
                   0,
                   0,
                   PLAN_STMT_UNKNOWN);
}

References fb(), INT64CONST, IsA, nesting_level, ParseState::p_sourcetext, pgss, pgss_enabled, pgss_hash, PGSS_INVALID, pgss_store(), pgss_track_utility, PLAN_STMT_UNKNOWN, prev_post_parse_analyze_hook, Query::stmt_location, and Query::utilityStmt.

Referenced by _PG_init().

pgss_ProcessUtility()

static void pgss_ProcessUtility ( PlannedStmt *  pstmt, const char *  queryString, bool  readOnlyTree, ProcessUtilityContext  context, ParamListInfo  params, QueryEnvironment *  queryEnv, DestReceiver *  dest, QueryCompletion *  qc  )

static

Definition at line 1092 of file pg_stat_statements.c.

{
    Node       *parsetree = pstmt->utilityStmt;
    int64       saved_queryId = pstmt->queryId;
    int         saved_stmt_location = pstmt->stmt_location;
    int         saved_stmt_len = pstmt->stmt_len;
    bool        enabled = pgss_track_utility && pgss_enabled(nesting_level);
 
    /*
     * Force utility statements to get queryId zero.  We do this even in cases
     * where the statement contains an optimizable statement for which a
     * queryId could be derived (such as EXPLAIN or DECLARE CURSOR).  For such
     * cases, runtime control will first go through ProcessUtility and then
     * the executor, and we don't want the executor hooks to do anything,
     * since we are already measuring the statement's costs at the utility
     * level.
     *
     * Note that this is only done if pg_stat_statements is enabled and
     * configured to track utility statements, in the unlikely possibility
     * that user configured another extension to handle utility statements
     * only.
     */
    if (enabled)
        pstmt->queryId = INT64CONST(0);
 
    /*
     * If it's an EXECUTE statement, we don't track it and don't increment the
     * nesting level.  This allows the cycles to be charged to the underlying
     * PREPARE instead (by the Executor hooks), which is much more useful.
     *
     * We also don't track execution of PREPARE.  If we did, we would get one
     * hash table entry for the PREPARE (with hash calculated from the query
     * string), and then a different one with the same query string (but hash
     * calculated from the query tree) would be used to accumulate costs of
     * ensuing EXECUTEs.  This would be confusing.  Since PREPARE doesn't
     * actually run the planner (only parse+rewrite), its costs are generally
     * pretty negligible and it seems okay to just ignore it.
     */
    if (enabled &&
        !IsA(parsetree, ExecuteStmt) &&
        !IsA(parsetree, PrepareStmt))
    {
        instr_time  start;
        instr_time  duration;
        uint64      rows;
        BufferUsage bufusage_start,
                    bufusage;
        WalUsage    walusage_start,
                    walusage;
 
        bufusage_start = pgBufferUsage;
        walusage_start = pgWalUsage;
        INSTR_TIME_SET_CURRENT(start);
 
        nesting_level++;
        PG_TRY();
        {
            if (prev_ProcessUtility)
                prev_ProcessUtility(pstmt, queryString, readOnlyTree,
                                    context, params, queryEnv,
                                    dest, qc);
            else
                standard_ProcessUtility(pstmt, queryString, readOnlyTree,
                                        context, params, queryEnv,
                                        dest, qc);
        }
        PG_FINALLY();
        {
            nesting_level--;
        }
        PG_END_TRY();
 
        /*
         * CAUTION: do not access the *pstmt data structure again below here.
         * If it was a ROLLBACK or similar, that data structure may have been
         * freed.  We must copy everything we still need into local variables,
         * which we did above.
         *
         * For the same reason, we can't risk restoring pstmt->queryId to its
         * former value, which'd otherwise be a good idea.
         */
 
        INSTR_TIME_SET_CURRENT(duration);
        INSTR_TIME_SUBTRACT(duration, start);
 
        /*
         * Track the total number of rows retrieved or affected by the utility
         * statements of COPY, FETCH, CREATE TABLE AS, CREATE MATERIALIZED
         * VIEW, REFRESH MATERIALIZED VIEW and SELECT INTO.
         */
        rows = (qc && (qc->commandTag == CMDTAG_COPY ||
                       qc->commandTag == CMDTAG_FETCH ||
                       qc->commandTag == CMDTAG_SELECT ||
                       qc->commandTag == CMDTAG_REFRESH_MATERIALIZED_VIEW)) ?
            qc->nprocessed : 0;
 
        /* calc differences of buffer counters. */
        memset(&bufusage, 0, sizeof(BufferUsage));
        BufferUsageAccumDiff(&bufusage, &pgBufferUsage, &bufusage_start);
 
        /* calc differences of WAL counters. */
        memset(&walusage, 0, sizeof(WalUsage));
        WalUsageAccumDiff(&walusage, &pgWalUsage, &walusage_start);
 
        pgss_store(queryString,
                   saved_queryId,
                   saved_stmt_location,
                   saved_stmt_len,
                   PGSS_EXEC,
                   INSTR_TIME_GET_MILLISEC(duration),
                   rows,
                   &bufusage,
                   &walusage,
                   NULL,
                   NULL,
                   0,
                   0,
                   pstmt->planOrigin);
    }
    else
    {
        /*
         * Even though we're not tracking execution time for this statement,
         * we must still increment the nesting level, to ensure that functions
         * evaluated within it are not seen as top-level calls.  But don't do
         * so for EXECUTE; that way, when control reaches pgss_planner or
         * pgss_ExecutorStart, we will treat the costs as top-level if
         * appropriate.  Likewise, don't bump for PREPARE, so that parse
         * analysis will treat the statement as top-level if appropriate.
         *
         * To be absolutely certain we don't mess up the nesting level,
         * evaluate the bump_level condition just once.
         */
        bool        bump_level =
            !IsA(parsetree, ExecuteStmt) &&
            !IsA(parsetree, PrepareStmt);
 
        if (bump_level)
            nesting_level++;
        PG_TRY();
        {
            if (prev_ProcessUtility)
                prev_ProcessUtility(pstmt, queryString, readOnlyTree,
                                    context, params, queryEnv,
                                    dest, qc);
            else
                standard_ProcessUtility(pstmt, queryString, readOnlyTree,
                                        context, params, queryEnv,
                                        dest, qc);
        }
        PG_FINALLY();
        {
            if (bump_level)
                nesting_level--;
        }
        PG_END_TRY();
    }
}

References BufferUsageAccumDiff(), QueryCompletion::commandTag, duration, fb(), INSTR_TIME_GET_MILLISEC, INSTR_TIME_SET_CURRENT, INSTR_TIME_SUBTRACT, INT64CONST, IsA, nesting_level, QueryCompletion::nprocessed, PG_END_TRY, PG_FINALLY, PG_TRY, pgBufferUsage, pgss_enabled, PGSS_EXEC, pgss_store(), pgss_track_utility, pgWalUsage, PlannedStmt::planOrigin, prev_ProcessUtility, PlannedStmt::queryId, standard_ProcessUtility(), start, PlannedStmt::stmt_len, PlannedStmt::stmt_location, PlannedStmt::utilityStmt, and WalUsageAccumDiff().

Referenced by _PG_init().

pgss_shmem_init()

static void pgss_shmem_init ( void *  arg )

static

Definition at line 530 of file pg_stat_statements.c.

{
    int         tranche_id;
    FILE       *file = NULL;
    FILE       *qfile = NULL;
    uint32      header;
    int32       num;
    int32       pgver;
    int32       i;
    int         buffer_size;
    char       *buffer = NULL;
 
    /*
     * We already checked that we're loaded from shared_preload_libraries in
     * _PG_init(), so we should not get here after postmaster startup.
     */
    Assert(!IsUnderPostmaster);
 
    /*
     * Initialize the shmem area with no statistics.
     */
    tranche_id = LWLockNewTrancheId("pg_stat_statements");
    LWLockInitialize(&pgss->lock.lock, tranche_id);
    pgss->cur_median_usage = ASSUMED_MEDIAN_INIT;
    pgss->mean_query_len = ASSUMED_LENGTH_INIT;
    SpinLockInit(&pgss->mutex);
    pgss->extent = 0;
    pgss->n_writers = 0;
    pgss->gc_count = 0;
    pgss->stats.dealloc = 0;
    pgss->stats.stats_reset = GetCurrentTimestamp();
 
    /* The hash table must've also been initialized by now */
    Assert(pgss_hash != NULL);
 
    /*
     * Set up a shmem exit hook to dump the statistics to disk on postmaster
     * (or standalone backend) exit.
     */
    on_shmem_exit(pgss_shmem_shutdown, (Datum) 0);
 
    /*
     * Load any pre-existing statistics from file.
     *
     * Note: we don't bother with locks here, because there should be no other
     * processes running when this code is reached.
     */
 
    /* Unlink query text file possibly left over from crash */
    unlink(PGSS_TEXT_FILE);
 
    /* Allocate new query text temp file */
    qfile = AllocateFile(PGSS_TEXT_FILE, PG_BINARY_W);
    if (qfile == NULL)
        goto write_error;
 
    /*
     * If we were told not to load old statistics, we're done.  (Note we do
     * not try to unlink any old dump file in this case.  This seems a bit
     * questionable but it's the historical behavior.)
     */
    if (!pgss_save)
    {
        FreeFile(qfile);
        return;
    }
 
    /*
     * Attempt to load old statistics from the dump file.
     */
    file = AllocateFile(PGSS_DUMP_FILE, PG_BINARY_R);
    if (file == NULL)
    {
        if (errno != ENOENT)
            goto read_error;
        /* No existing persisted stats file, so we're done */
        FreeFile(qfile);
        return;
    }
 
    buffer_size = 2048;
    buffer = (char *) palloc(buffer_size);
 
    if (fread(&header, sizeof(uint32), 1, file) != 1 ||
        fread(&pgver, sizeof(uint32), 1, file) != 1 ||
        fread(&num, sizeof(int32), 1, file) != 1)
        goto read_error;
 
    if (header != PGSS_FILE_HEADER ||
        pgver != PGSS_PG_MAJOR_VERSION)
        goto data_error;
 
    for (i = 0; i < num; i++)
    {
        pgssEntry   temp;
        pgssEntry  *entry;
        Size        query_offset;
 
        if (fread(&temp, sizeof(pgssEntry), 1, file) != 1)
            goto read_error;
 
        /* Encoding is the only field we can easily sanity-check */
        if (!PG_VALID_BE_ENCODING(temp.encoding))
            goto data_error;
 
        /* Resize buffer as needed */
        if (temp.query_len >= buffer_size)
        {
            buffer_size = Max(buffer_size * 2, temp.query_len + 1);
            buffer = repalloc(buffer, buffer_size);
        }
 
        if (fread(buffer, 1, temp.query_len + 1, file) != temp.query_len + 1)
            goto read_error;
 
        /* Should have a trailing null, but let's make sure */
        buffer[temp.query_len] = '\0';
 
        /* Skip loading "sticky" entries */
        if (IS_STICKY(temp.counters))
            continue;
 
        /* Store the query text */
        query_offset = pgss->extent;
        if (fwrite(buffer, 1, temp.query_len + 1, qfile) != temp.query_len + 1)
            goto write_error;
        pgss->extent += temp.query_len + 1;
 
        /* make the hashtable entry (discards old entries if too many) */
        entry = entry_alloc(&temp.key, query_offset, temp.query_len,
                            temp.encoding,
                            false);
 
        /* copy in the actual stats */
        entry->counters = temp.counters;
        entry->stats_since = temp.stats_since;
        entry->minmax_stats_since = temp.minmax_stats_since;
    }
 
    /* Read global statistics for pg_stat_statements */
    if (fread(&pgss->stats, sizeof(pgssGlobalStats), 1, file) != 1)
        goto read_error;
 
    pfree(buffer);
    FreeFile(file);
    FreeFile(qfile);
 
    /*
     * Remove the persisted stats file so it's not included in
     * backups/replication standbys, etc.  A new file will be written on next
     * shutdown.
     *
     * Note: it's okay if the PGSS_TEXT_FILE is included in a basebackup,
     * because we remove that file on startup; it acts inversely to
     * PGSS_DUMP_FILE, in that it is only supposed to be around when the
     * server is running, whereas PGSS_DUMP_FILE is only supposed to be around
     * when the server is not running.  Leaving the file creates no danger of
     * a newly restored database having a spurious record of execution costs,
     * which is what we're really concerned about here.
     */
    unlink(PGSS_DUMP_FILE);
 
    return;
 
read_error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not read file \"%s\": %m",
                    PGSS_DUMP_FILE)));
    goto fail;
data_error:
    ereport(LOG,
            (errcode(ERRCODE_INVALID_PARAMETER_VALUE),
             errmsg("ignoring invalid data in file \"%s\"",
                    PGSS_DUMP_FILE)));
    goto fail;
write_error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not write file \"%s\": %m",
                    PGSS_TEXT_FILE)));
fail:
    if (buffer)
        pfree(buffer);
    if (file)
        FreeFile(file);
    if (qfile)
        FreeFile(qfile);
    /* If possible, throw away the bogus file; ignore any error */
    unlink(PGSS_DUMP_FILE);
 
    /*
     * Don't unlink PGSS_TEXT_FILE here; it should always be around while the
     * server is running with pg_stat_statements enabled
     */
}

References AllocateFile(), Assert, ASSUMED_LENGTH_INIT, ASSUMED_MEDIAN_INIT, pgssEntry::counters, pgssSharedState::cur_median_usage, pgssGlobalStats::dealloc, entry_alloc(), ereport, errcode(), errcode_for_file_access(), errmsg, pgssSharedState::extent, fb(), FreeFile(), pgssSharedState::gc_count, GetCurrentTimestamp(), i, IS_STICKY, IsUnderPostmaster, pgssSharedState::lock, LWLockPadded::lock, LOG, LWLockInitialize(), LWLockNewTrancheId(), Max, pgssSharedState::mean_query_len, pgssEntry::minmax_stats_since, pgssSharedState::mutex, pgssSharedState::n_writers, on_shmem_exit(), palloc(), pfree(), PG_BINARY_R, PG_BINARY_W, PG_VALID_BE_ENCODING, pgss, PGSS_DUMP_FILE, PGSS_FILE_HEADER, pgss_hash, PGSS_PG_MAJOR_VERSION, pgss_save, pgss_shmem_shutdown(), PGSS_TEXT_FILE, repalloc(), SpinLockInit(), pgssSharedState::stats, pgssGlobalStats::stats_reset, and pgssEntry::stats_since.

pgss_shmem_request()

static void pgss_shmem_request ( void *  arg )

static

Definition at line 506 of file pg_stat_statements.c.

{
    ShmemRequestHash(.name = "pg_stat_statements hash",
                     .nelems = pgss_max,
                     .hash_info.keysize = sizeof(pgssHashKey),
                     .hash_info.entrysize = sizeof(pgssEntry),
                     .hash_flags = HASH_ELEM | HASH_BLOBS,
                     .ptr = &pgss_hash,
        );
    ShmemRequestStruct(.name = "pg_stat_statements",
                       .size = sizeof(pgssSharedState),
                       .ptr = (void **) &pgss,
        );
}

References HASH_BLOBS, HASH_ELEM, name, pgss, pgss_hash, pgss_max, ShmemRequestHash, and ShmemRequestStruct.

pgss_shmem_shutdown()

static void pgss_shmem_shutdown ( int  code, Datum  arg  )

static

Definition at line 734 of file pg_stat_statements.c.

{
    FILE       *file;
    char       *qbuffer = NULL;
    Size        qbuffer_size = 0;
    HASH_SEQ_STATUS hash_seq;
    int32       num_entries;
    pgssEntry  *entry;
 
    /* Don't try to dump during a crash. */
    if (code)
        return;
 
    /* Safety check ... shouldn't get here unless shmem is set up. */
    if (!pgss || !pgss_hash)
        return;
 
    /* Don't dump if told not to. */
    if (!pgss_save)
        return;
 
    file = AllocateFile(PGSS_DUMP_FILE ".tmp", PG_BINARY_W);
    if (file == NULL)
        goto error;
 
    if (fwrite(&PGSS_FILE_HEADER, sizeof(uint32), 1, file) != 1)
        goto error;
    if (fwrite(&PGSS_PG_MAJOR_VERSION, sizeof(uint32), 1, file) != 1)
        goto error;
    num_entries = hash_get_num_entries(pgss_hash);
    if (fwrite(&num_entries, sizeof(int32), 1, file) != 1)
        goto error;
 
    qbuffer = qtext_load_file(&qbuffer_size);
    if (qbuffer == NULL)
        goto error;
 
    /*
     * When serializing to disk, we store query texts immediately after their
     * entry data.  Any orphaned query texts are thereby excluded.
     */
    hash_seq_init(&hash_seq, pgss_hash);
    while ((entry = hash_seq_search(&hash_seq)) != NULL)
    {
        int         len = entry->query_len;
        char       *qstr = qtext_fetch(entry->query_offset, len,
                                       qbuffer, qbuffer_size);
 
        if (qstr == NULL)
            continue;           /* Ignore any entries with bogus texts */
 
        if (fwrite(entry, sizeof(pgssEntry), 1, file) != 1 ||
            fwrite(qstr, 1, len + 1, file) != len + 1)
        {
            /* note: we assume hash_seq_term won't change errno */
            hash_seq_term(&hash_seq);
            goto error;
        }
    }
 
    /* Dump global statistics for pg_stat_statements */
    if (fwrite(&pgss->stats, sizeof(pgssGlobalStats), 1, file) != 1)
        goto error;
 
    pfree(qbuffer);
    qbuffer = NULL;
 
    if (FreeFile(file))
    {
        file = NULL;
        goto error;
    }
 
    /*
     * Rename file into place, so we atomically replace any old one.
     */
    (void) durable_rename(PGSS_DUMP_FILE ".tmp", PGSS_DUMP_FILE, LOG);
 
    /* Unlink query-texts file; it's not needed while shutdown */
    unlink(PGSS_TEXT_FILE);
 
    return;
 
error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not write file \"%s\": %m",
                    PGSS_DUMP_FILE ".tmp")));
    if (qbuffer)
        pfree(qbuffer);
    if (file)
        FreeFile(file);
    unlink(PGSS_DUMP_FILE ".tmp");
    unlink(PGSS_TEXT_FILE);
}

References AllocateFile(), durable_rename(), ereport, errcode_for_file_access(), errmsg, error(), fb(), FreeFile(), hash_get_num_entries(), hash_seq_init(), hash_seq_search(), hash_seq_term(), len, LOG, pfree(), PG_BINARY_W, pgss, PGSS_DUMP_FILE, PGSS_FILE_HEADER, pgss_hash, PGSS_PG_MAJOR_VERSION, pgss_save, PGSS_TEXT_FILE, qtext_fetch(), qtext_load_file(), pgssEntry::query_len, pgssEntry::query_offset, and pgssSharedState::stats.

Referenced by pgss_shmem_init().

pgss_store()

static void pgss_store ( const char *  query, int64  queryId, int  query_location, int  query_len, pgssStoreKind  kind, double  total_time, uint64  rows, const BufferUsage *  bufusage, const WalUsage *  walusage, const struct JitInstrumentation *  jitusage, const JumbleState *  jstate, int  parallel_workers_to_launch, int  parallel_workers_launched, PlannedStmtOrigin  planOrigin  )

static

Definition at line 1267 of file pg_stat_statements.c.

{
    pgssHashKey key;
    pgssEntry  *entry;
    char       *norm_query = NULL;
    int         encoding = GetDatabaseEncoding();
 
    Assert(query != NULL);
 
    /* Safety check... */
    if (!pgss || !pgss_hash)
        return;
 
    /*
     * Nothing to do if compute_query_id isn't enabled and no other module
     * computed a query identifier.
     */
    if (queryId == INT64CONST(0))
        return;
 
    /*
     * Confine our attention to the relevant part of the string, if the query
     * is a portion of a multi-statement source string, and update query
     * location and length if needed.
     */
    query = CleanQuerytext(query, &query_location, &query_len);
 
    /* Set up key for hashtable search */
 
    /* clear padding */
    memset(&key, 0, sizeof(pgssHashKey));
 
    key.userid = GetUserId();
    key.dbid = MyDatabaseId;
    key.queryid = queryId;
    key.toplevel = (nesting_level == 0);
 
    /* Lookup the hash table entry with shared lock. */
    LWLockAcquire(&pgss->lock.lock, LW_SHARED);
 
    entry = (pgssEntry *) hash_search(pgss_hash, &key, HASH_FIND, NULL);
 
    /* Create new entry, if not present */
    if (!entry)
    {
        Size        query_offset;
        int         gc_count;
        bool        stored;
        bool        do_gc;
 
        /*
         * Create a new, normalized query string if caller asked.  We don't
         * need to hold the lock while doing this work.  (Note: in any case,
         * it's possible that someone else creates a duplicate hashtable entry
         * in the interval where we don't hold the lock below.  That case is
         * handled by entry_alloc.)
         */
        if (jstate)
        {
            LWLockRelease(&pgss->lock.lock);
            norm_query = generate_normalized_query(jstate, query,
                                                   query_location,
                                                   &query_len);
            LWLockAcquire(&pgss->lock.lock, LW_SHARED);
        }
 
        /* Append new query text to file with only shared lock held */
        stored = qtext_store(norm_query ? norm_query : query, query_len,
                             &query_offset, &gc_count);
 
        /*
         * Determine whether we need to garbage collect external query texts
         * while the shared lock is still held.  This micro-optimization
         * avoids taking the time to decide this while holding exclusive lock.
         */
        do_gc = need_gc_qtexts();
 
        /* Need exclusive lock to make a new hashtable entry - promote */
        LWLockRelease(&pgss->lock.lock);
        LWLockAcquire(&pgss->lock.lock, LW_EXCLUSIVE);
 
        /*
         * A garbage collection may have occurred while we weren't holding the
         * lock.  In the unlikely event that this happens, the query text we
         * stored above will have been garbage collected, so write it again.
         * This should be infrequent enough that doing it while holding
         * exclusive lock isn't a performance problem.
         */
        if (!stored || pgss->gc_count != gc_count)
            stored = qtext_store(norm_query ? norm_query : query, query_len,
                                 &query_offset, NULL);
 
        /* If we failed to write to the text file, give up */
        if (!stored)
            goto done;
 
        /* OK to create a new hashtable entry */
        entry = entry_alloc(&key, query_offset, query_len, encoding,
                            jstate != NULL);
 
        /* If needed, perform garbage collection while exclusive lock held */
        if (do_gc)
            gc_qtexts();
    }
 
    /* Increment the counts, except when jstate is not NULL */
    if (!jstate)
    {
        Assert(kind == PGSS_PLAN || kind == PGSS_EXEC);
 
        /*
         * Grab the spinlock while updating the counters (see comment about
         * locking rules at the head of the file)
         */
        SpinLockAcquire(&entry->mutex);
 
        /* "Unstick" entry if it was previously sticky */
        if (IS_STICKY(entry->counters))
            entry->counters.usage = USAGE_INIT;
 
        entry->counters.calls[kind] += 1;
        entry->counters.total_time[kind] += total_time;
 
        if (entry->counters.calls[kind] == 1)
        {
            entry->counters.min_time[kind] = total_time;
            entry->counters.max_time[kind] = total_time;
            entry->counters.mean_time[kind] = total_time;
        }
        else
        {
            /*
             * Welford's method for accurately computing variance. See
             * <http://www.johndcook.com/blog/standard_deviation/>
             */
            double      old_mean = entry->counters.mean_time[kind];
 
            entry->counters.mean_time[kind] +=
                (total_time - old_mean) / entry->counters.calls[kind];
            entry->counters.sum_var_time[kind] +=
                (total_time - old_mean) * (total_time - entry->counters.mean_time[kind]);
 
            /*
             * Calculate min and max time. min = 0 and max = 0 means that the
             * min/max statistics were reset
             */
            if (entry->counters.min_time[kind] == 0
                && entry->counters.max_time[kind] == 0)
            {
                entry->counters.min_time[kind] = total_time;
                entry->counters.max_time[kind] = total_time;
            }
            else
            {
                if (entry->counters.min_time[kind] > total_time)
                    entry->counters.min_time[kind] = total_time;
                if (entry->counters.max_time[kind] < total_time)
                    entry->counters.max_time[kind] = total_time;
            }
        }
        entry->counters.rows += rows;
        entry->counters.shared_blks_hit += bufusage->shared_blks_hit;
        entry->counters.shared_blks_read += bufusage->shared_blks_read;
        entry->counters.shared_blks_dirtied += bufusage->shared_blks_dirtied;
        entry->counters.shared_blks_written += bufusage->shared_blks_written;
        entry->counters.local_blks_hit += bufusage->local_blks_hit;
        entry->counters.local_blks_read += bufusage->local_blks_read;
        entry->counters.local_blks_dirtied += bufusage->local_blks_dirtied;
        entry->counters.local_blks_written += bufusage->local_blks_written;
        entry->counters.temp_blks_read += bufusage->temp_blks_read;
        entry->counters.temp_blks_written += bufusage->temp_blks_written;
        entry->counters.shared_blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->shared_blk_read_time);
        entry->counters.shared_blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->shared_blk_write_time);
        entry->counters.local_blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->local_blk_read_time);
        entry->counters.local_blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->local_blk_write_time);
        entry->counters.temp_blk_read_time += INSTR_TIME_GET_MILLISEC(bufusage->temp_blk_read_time);
        entry->counters.temp_blk_write_time += INSTR_TIME_GET_MILLISEC(bufusage->temp_blk_write_time);
        entry->counters.usage += USAGE_EXEC(total_time);
        entry->counters.wal_records += walusage->wal_records;
        entry->counters.wal_fpi += walusage->wal_fpi;
        entry->counters.wal_bytes += walusage->wal_bytes;
        entry->counters.wal_buffers_full += walusage->wal_buffers_full;
        if (jitusage)
        {
            entry->counters.jit_functions += jitusage->created_functions;
            entry->counters.jit_generation_time += INSTR_TIME_GET_MILLISEC(jitusage->generation_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->deform_counter))
                entry->counters.jit_deform_count++;
            entry->counters.jit_deform_time += INSTR_TIME_GET_MILLISEC(jitusage->deform_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->inlining_counter))
                entry->counters.jit_inlining_count++;
            entry->counters.jit_inlining_time += INSTR_TIME_GET_MILLISEC(jitusage->inlining_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->optimization_counter))
                entry->counters.jit_optimization_count++;
            entry->counters.jit_optimization_time += INSTR_TIME_GET_MILLISEC(jitusage->optimization_counter);
 
            if (INSTR_TIME_GET_MILLISEC(jitusage->emission_counter))
                entry->counters.jit_emission_count++;
            entry->counters.jit_emission_time += INSTR_TIME_GET_MILLISEC(jitusage->emission_counter);
        }
 
        /* parallel worker counters */
        entry->counters.parallel_workers_to_launch += parallel_workers_to_launch;
        entry->counters.parallel_workers_launched += parallel_workers_launched;
 
        /* plan cache counters */
        if (planOrigin == PLAN_STMT_CACHE_GENERIC)
            entry->counters.generic_plan_calls++;
        else if (planOrigin == PLAN_STMT_CACHE_CUSTOM)
            entry->counters.custom_plan_calls++;
 
        SpinLockRelease(&entry->mutex);
    }
 
done:
    LWLockRelease(&pgss->lock.lock);
 
    /* We postpone this clean-up until we're out of the lock */
    if (norm_query)
        pfree(norm_query);
}

References Assert, Counters::calls, CleanQuerytext(), pgssEntry::counters, Counters::custom_plan_calls, encoding, entry_alloc(), fb(), pgssSharedState::gc_count, gc_qtexts(), generate_normalized_query(), Counters::generic_plan_calls, GetDatabaseEncoding(), GetUserId(), HASH_FIND, hash_search(), INSTR_TIME_GET_MILLISEC, INT64CONST, IS_STICKY, Counters::jit_deform_count, Counters::jit_deform_time, Counters::jit_emission_count, Counters::jit_emission_time, Counters::jit_functions, Counters::jit_generation_time, Counters::jit_inlining_count, Counters::jit_inlining_time, Counters::jit_optimization_count, Counters::jit_optimization_time, Counters::local_blk_read_time, BufferUsage::local_blk_read_time, Counters::local_blk_write_time, BufferUsage::local_blk_write_time, Counters::local_blks_dirtied, BufferUsage::local_blks_dirtied, Counters::local_blks_hit, BufferUsage::local_blks_hit, Counters::local_blks_read, BufferUsage::local_blks_read, Counters::local_blks_written, BufferUsage::local_blks_written, pgssSharedState::lock, LWLockPadded::lock, LW_EXCLUSIVE, LW_SHARED, LWLockAcquire(), LWLockRelease(), Counters::max_time, Counters::mean_time, Counters::min_time, pgssEntry::mutex, MyDatabaseId, need_gc_qtexts(), nesting_level, Counters::parallel_workers_launched, Counters::parallel_workers_to_launch, pfree(), pgss, PGSS_EXEC, pgss_hash, PGSS_PLAN, PLAN_STMT_CACHE_CUSTOM, PLAN_STMT_CACHE_GENERIC, qtext_store(), Counters::rows, Counters::shared_blk_read_time, BufferUsage::shared_blk_read_time, Counters::shared_blk_write_time, BufferUsage::shared_blk_write_time, Counters::shared_blks_dirtied, BufferUsage::shared_blks_dirtied, Counters::shared_blks_hit, BufferUsage::shared_blks_hit, Counters::shared_blks_read, BufferUsage::shared_blks_read, Counters::shared_blks_written, BufferUsage::shared_blks_written, SpinLockAcquire(), SpinLockRelease(), Counters::sum_var_time, Counters::temp_blk_read_time, BufferUsage::temp_blk_read_time, Counters::temp_blk_write_time, BufferUsage::temp_blk_write_time, Counters::temp_blks_read, BufferUsage::temp_blks_read, Counters::temp_blks_written, BufferUsage::temp_blks_written, Counters::total_time, Counters::usage, USAGE_EXEC, USAGE_INIT, Counters::wal_buffers_full, WalUsage::wal_buffers_full, Counters::wal_bytes, WalUsage::wal_bytes, Counters::wal_fpi, WalUsage::wal_fpi, Counters::wal_records, and WalUsage::wal_records.

Referenced by pgss_ExecutorEnd(), pgss_planner(), pgss_post_parse_analyze(), and pgss_ProcessUtility().

qtext_fetch()

static char * qtext_fetch ( Size  query_offset, int  query_len, char *  buffer, Size  buffer_size  )

static

Definition at line 2402 of file pg_stat_statements.c.

{
    /* File read failed? */
    if (buffer == NULL)
        return NULL;
    /* Bogus offset/length? */
    if (query_len < 0 ||
        query_offset + query_len >= buffer_size)
        return NULL;
    /* As a further sanity check, make sure there's a trailing null */
    if (buffer[query_offset + query_len] != '\0')
        return NULL;
    /* Looks OK */
    return buffer + query_offset;
}

References fb().

Referenced by gc_qtexts(), pg_stat_statements_internal(), and pgss_shmem_shutdown().

qtext_load_file()

static char * qtext_load_file ( Size *  buffer_size )

static

Definition at line 2309 of file pg_stat_statements.c.

{
    char       *buf;
    int         fd;
    struct stat stat;
    Size        nread;
 
    fd = OpenTransientFile(PGSS_TEXT_FILE, O_RDONLY | PG_BINARY);
    if (fd < 0)
    {
        if (errno != ENOENT)
            ereport(LOG,
                    (errcode_for_file_access(),
                     errmsg("could not read file \"%s\": %m",
                            PGSS_TEXT_FILE)));
        return NULL;
    }
 
    /* Get file length */
    if (fstat(fd, &stat))
    {
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not stat file \"%s\": %m",
                        PGSS_TEXT_FILE)));
        CloseTransientFile(fd);
        return NULL;
    }
 
    /* Allocate buffer; beware that off_t might be wider than size_t */
    if (stat.st_size <= MaxAllocHugeSize)
        buf = (char *) palloc_extended(stat.st_size, MCXT_ALLOC_HUGE | MCXT_ALLOC_NO_OOM);
    else
        buf = NULL;
    if (buf == NULL)
    {
        ereport(LOG,
                (errcode(ERRCODE_OUT_OF_MEMORY),
                 errmsg("out of memory"),
                 errdetail("Could not allocate enough memory to read file \"%s\".",
                           PGSS_TEXT_FILE)));
        CloseTransientFile(fd);
        return NULL;
    }
 
    /*
     * OK, slurp in the file.  Windows fails if we try to read more than
     * INT_MAX bytes at once, and other platforms might not like that either,
     * so read a very large file in 1GB segments.
     */
    nread = 0;
    while (nread < stat.st_size)
    {
        int         toread = Min(1024 * 1024 * 1024, stat.st_size - nread);
 
        /*
         * If we get a short read and errno doesn't get set, the reason is
         * probably that garbage collection truncated the file since we did
         * the fstat(), so we don't log a complaint --- but we don't return
         * the data, either, since it's most likely corrupt due to concurrent
         * writes from garbage collection.
         */
        errno = 0;
        if (read(fd, buf + nread, toread) != toread)
        {
            if (errno)
                ereport(LOG,
                        (errcode_for_file_access(),
                         errmsg("could not read file \"%s\": %m",
                                PGSS_TEXT_FILE)));
            pfree(buf);
            CloseTransientFile(fd);
            return NULL;
        }
        nread += toread;
    }
 
    if (CloseTransientFile(fd) != 0)
        ereport(LOG,
                (errcode_for_file_access(),
                 errmsg("could not close file \"%s\": %m", PGSS_TEXT_FILE)));
 
    *buffer_size = nread;
    return buf;
}

References buf, CloseTransientFile(), ereport, errcode(), errcode_for_file_access(), errdetail(), errmsg, fb(), fd(), fstat, LOG, MaxAllocHugeSize, MCXT_ALLOC_HUGE, MCXT_ALLOC_NO_OOM, Min, OpenTransientFile(), palloc_extended(), pfree(), PG_BINARY, PGSS_TEXT_FILE, read, and stat::st_size.

Referenced by gc_qtexts(), pg_stat_statements_internal(), and pgss_shmem_shutdown().

qtext_store()

static bool qtext_store ( const char *  query, int  query_len, Size *  query_offset, int *  gc_count  )

static

Definition at line 2229 of file pg_stat_statements.c.

{
    Size        off;
    int         fd;
 
    /*
     * We use a spinlock to protect extent/n_writers/gc_count, so that
     * multiple processes may execute this function concurrently.
     */
    SpinLockAcquire(&pgss->mutex);
    off = pgss->extent;
    pgss->extent += query_len + 1;
    pgss->n_writers++;
    if (gc_count)
        *gc_count = pgss->gc_count;
    SpinLockRelease(&pgss->mutex);
 
    *query_offset = off;
 
    /*
     * Don't allow the file to grow larger than what qtext_load_file can
     * (theoretically) handle.  This has been seen to be reachable on 32-bit
     * platforms.
     */
    if (unlikely(query_len >= MaxAllocHugeSize - off))
    {
        errno = EFBIG;          /* not quite right, but it'll do */
        fd = -1;
        goto error;
    }
 
    /* Now write the data into the successfully-reserved part of the file */
    fd = OpenTransientFile(PGSS_TEXT_FILE, O_RDWR | O_CREAT | PG_BINARY);
    if (fd < 0)
        goto error;
 
    if (pg_pwrite(fd, query, query_len, off) != query_len)
        goto error;
    if (pg_pwrite(fd, "\0", 1, off + query_len) != 1)
        goto error;
 
    CloseTransientFile(fd);
 
    /* Mark our write complete */
    SpinLockAcquire(&pgss->mutex);
    pgss->n_writers--;
    SpinLockRelease(&pgss->mutex);
 
    return true;
 
error:
    ereport(LOG,
            (errcode_for_file_access(),
             errmsg("could not write file \"%s\": %m",
                    PGSS_TEXT_FILE)));
 
    if (fd >= 0)
        CloseTransientFile(fd);
 
    /* Mark our write complete */
    SpinLockAcquire(&pgss->mutex);
    pgss->n_writers--;
    SpinLockRelease(&pgss->mutex);
 
    return false;
}

References CloseTransientFile(), ereport, errcode_for_file_access(), errmsg, error(), pgssSharedState::extent, fb(), fd(), pgssSharedState::gc_count, LOG, MaxAllocHugeSize, pgssSharedState::mutex, pgssSharedState::n_writers, OpenTransientFile(), PG_BINARY, pg_pwrite, pgss, PGSS_TEXT_FILE, SpinLockAcquire(), SpinLockRelease(), and unlikely.

Referenced by pgss_store().

Variable Documentation

nesting_level

int nesting_level = 0

static

Definition at line 275 of file pg_stat_statements.c.

Referenced by pgss_ExecutorEnd(), pgss_ExecutorFinish(), pgss_ExecutorRun(), pgss_ExecutorStart(), pgss_planner(), pgss_post_parse_analyze(), pgss_ProcessUtility(), and pgss_store().

pgss

pgssSharedState* pgss

static

Definition at line 261 of file pg_stat_statements.c.

Referenced by entry_alloc(), entry_dealloc(), entry_reset(), gc_qtexts(), need_gc_qtexts(), pg_stat_statements_info(), pg_stat_statements_internal(), pgss_post_parse_analyze(), pgss_shmem_init(), pgss_shmem_request(), pgss_shmem_shutdown(), pgss_store(), and qtext_store().

PGSS_FILE_HEADER

const uint32 PGSS_FILE_HEADER = 0x20250731

static

Definition at line 88 of file pg_stat_statements.c.

Referenced by pgss_shmem_init(), and pgss_shmem_shutdown().

pgss_hash

HTAB* pgss_hash

static

Definition at line 262 of file pg_stat_statements.c.

Referenced by entry_alloc(), entry_dealloc(), entry_reset(), gc_qtexts(), pg_stat_statements_info(), pg_stat_statements_internal(), pgss_post_parse_analyze(), pgss_shmem_init(), pgss_shmem_request(), pgss_shmem_shutdown(), and pgss_store().

pgss_max

int pgss_max = 5000

static

Definition at line 303 of file pg_stat_statements.c.

Referenced by _PG_init(), entry_alloc(), need_gc_qtexts(), and pgss_shmem_request().

PGSS_PG_MAJOR_VERSION

const uint32 PGSS_PG_MAJOR_VERSION = PG_VERSION_NUM / 100

static

Definition at line 91 of file pg_stat_statements.c.

Referenced by pgss_shmem_init(), and pgss_shmem_shutdown().

pgss_save

bool pgss_save = true

static

Definition at line 308 of file pg_stat_statements.c.

Referenced by _PG_init(), pgss_shmem_init(), and pgss_shmem_shutdown().

pgss_shmem_callbacks

const ShmemCallbacks pgss_shmem_callbacks

static

Initial value:

= {
    .request_fn = pgss_shmem_request,
    .init_fn = pgss_shmem_init,
}

Definition at line 267 of file pg_stat_statements.c.

                                                   {
    .request_fn = pgss_shmem_request,
    .init_fn = pgss_shmem_init,
};

Referenced by _PG_init().

pgss_track

int pgss_track = PGSS_TRACK_TOP

static

Definition at line 304 of file pg_stat_statements.c.

Referenced by _PG_init().

pgss_track_planning

bool pgss_track_planning = false

static

Definition at line 306 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_planner().

pgss_track_utility

bool pgss_track_utility = true

static

Definition at line 305 of file pg_stat_statements.c.

Referenced by _PG_init(), pgss_post_parse_analyze(), and pgss_ProcessUtility().

prev_ExecutorEnd

ExecutorEnd_hook_type prev_ExecutorEnd = NULL

static

Definition at line 283 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_ExecutorEnd().

prev_ExecutorFinish

ExecutorFinish_hook_type prev_ExecutorFinish = NULL

static

Definition at line 282 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_ExecutorFinish().

prev_ExecutorRun

ExecutorRun_hook_type prev_ExecutorRun = NULL

static

Definition at line 281 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_ExecutorRun().

prev_ExecutorStart

ExecutorStart_hook_type prev_ExecutorStart = NULL

static

Definition at line 280 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_ExecutorStart().

prev_planner_hook

planner_hook_type prev_planner_hook = NULL

static

Definition at line 279 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_planner().

prev_post_parse_analyze_hook

post_parse_analyze_hook_type prev_post_parse_analyze_hook = NULL

static

Definition at line 278 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_post_parse_analyze().

prev_ProcessUtility

ProcessUtility_hook_type prev_ProcessUtility = NULL

static

Definition at line 284 of file pg_stat_statements.c.

Referenced by _PG_init(), and pgss_ProcessUtility().

track_options

const struct config_enum_entry track_options[]

static

Initial value:

=
{
    {"none", PGSS_TRACK_NONE, false},
    {"top", PGSS_TRACK_TOP, false},
    {"all", PGSS_TRACK_ALL, false},
    {NULL, 0, false}
}

Definition at line 295 of file pg_stat_statements.c.

{
    {"none", PGSS_TRACK_NONE, false},
    {"top", PGSS_TRACK_TOP, false},
    {"all", PGSS_TRACK_ALL, false},
    {NULL, 0, false}
};

Referenced by _PG_init().