test_custom_var_stats.c File Reference

#include "postgres.h"
#include "common/hashfn.h"
#include "funcapi.h"
#include "utils/builtins.h"
#include "utils/pgstat_internal.h"

Include dependency graph for test_custom_var_stats.c:

Go to the source code of this file.

Data Structures
struct	PgStat_StatCustomVarEntry
struct	PgStatShared_CustomVarEntry

Macros
#define	PGSTAT_KIND_TEST_CUSTOM_VAR_STATS   25
#define	PGSTAT_CUSTOM_VAR_STATS_IDX(name)   hash_bytes_extended((const unsigned char *) name, strlen(name), 0)

Typedefs
typedef struct PgStat_StatCustomVarEntry	PgStat_StatCustomVarEntry
typedef struct PgStatShared_CustomVarEntry	PgStatShared_CustomVarEntry

Functions
	PG_MODULE_MAGIC_EXT (.name="test_custom_var_stats",.version=PG_VERSION)
static bool	test_custom_stats_var_flush_pending_cb (PgStat_EntryRef *entry_ref, bool nowait)
void	_PG_init (void)
static PgStat_StatCustomVarEntry *	test_custom_stats_var_fetch_entry (const char *stat_name)
	PG_FUNCTION_INFO_V1 (test_custom_stats_var_create)
Datum	test_custom_stats_var_create (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (test_custom_stats_var_update)
Datum	test_custom_stats_var_update (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (test_custom_stats_var_drop)
Datum	test_custom_stats_var_drop (PG_FUNCTION_ARGS)
	PG_FUNCTION_INFO_V1 (test_custom_stats_var_report)
Datum	test_custom_stats_var_report (PG_FUNCTION_ARGS)

Variables
static const PgStat_KindInfo	custom_stats

Macro Definition Documentation

PGSTAT_CUSTOM_VAR_STATS_IDX

#define PGSTAT_CUSTOM_VAR_STATS_IDX

(

name

)

hash_bytes_extended((const unsigned char *) name, strlen(name), 0)

Definition at line 38 of file test_custom_var_stats.c.

PGSTAT_KIND_TEST_CUSTOM_VAR_STATS

#define PGSTAT_KIND_TEST_CUSTOM_VAR_STATS   25

Definition at line 33 of file test_custom_var_stats.c.

Typedef Documentation

PgStat_StatCustomVarEntry

typedef struct PgStat_StatCustomVarEntry PgStat_StatCustomVarEntry

PgStatShared_CustomVarEntry

typedef struct PgStatShared_CustomVarEntry PgStatShared_CustomVarEntry

Function Documentation

_PG_init()

void _PG_init

(

void

)

Definition at line 91 of file test_custom_var_stats.c.

{
    /* Must be loaded via shared_preload_libraries */
    if (!process_shared_preload_libraries_in_progress)
        return;
 
    /* Register custom statistics kind */
    pgstat_register_kind(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, &custom_stats);
}

References custom_stats, PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, pgstat_register_kind(), and process_shared_preload_libraries_in_progress.

PG_FUNCTION_INFO_V1() [1/4]

PG_FUNCTION_INFO_V1

(

test_custom_stats_var_create

)

PG_FUNCTION_INFO_V1() [2/4]

PG_FUNCTION_INFO_V1

(

test_custom_stats_var_drop

)

PG_FUNCTION_INFO_V1() [3/4]

PG_FUNCTION_INFO_V1

(

test_custom_stats_var_report

)

PG_FUNCTION_INFO_V1() [4/4]

PG_FUNCTION_INFO_V1

(

test_custom_stats_var_update

)

PG_MODULE_MAGIC_EXT()

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

test_custom_stats_var_create()

Datum test_custom_stats_var_create

(

PG_FUNCTION_ARGS

)

Definition at line 170 of file test_custom_var_stats.c.

{
    PgStat_EntryRef *entry_ref;
    PgStatShared_CustomVarEntry *shared_entry;
    char       *stat_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 
    /* Validate name length first */
    if (strlen(stat_name) >= NAMEDATALEN)
        ereport(ERROR,
                (errcode(ERRCODE_NAME_TOO_LONG),
                 errmsg("custom statistic name \"%s\" is too long", stat_name),
                 errdetail("Name must be less than %d characters.", NAMEDATALEN)));
 
    /* Create or get existing entry */
    entry_ref = pgstat_get_entry_ref_locked(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, InvalidOid,
                                            PGSTAT_CUSTOM_VAR_STATS_IDX(stat_name), true);
 
    if (!entry_ref)
        PG_RETURN_VOID();
 
    shared_entry = (PgStatShared_CustomVarEntry *) entry_ref->shared_stats;
 
    /* Zero-initialize statistics */
    memset(&shared_entry->stats, 0, sizeof(shared_entry->stats));
 
    pgstat_unlock_entry(entry_ref);
 
    PG_RETURN_VOID();
}

References ereport, errcode(), errdetail(), errmsg(), ERROR, InvalidOid, NAMEDATALEN, PG_GETARG_TEXT_PP, PG_RETURN_VOID, PGSTAT_CUSTOM_VAR_STATS_IDX, pgstat_get_entry_ref_locked(), PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, pgstat_unlock_entry(), PgStat_EntryRef::shared_stats, PgStatShared_CustomVarEntry::stats, and text_to_cstring().

test_custom_stats_var_drop()

Datum test_custom_stats_var_drop

(

PG_FUNCTION_ARGS

)

Definition at line 234 of file test_custom_var_stats.c.

{
    char       *stat_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
 
    /* Drop entry and request GC if the entry could not be freed */
    if (!pgstat_drop_entry(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, InvalidOid,
                           PGSTAT_CUSTOM_VAR_STATS_IDX(stat_name)))
        pgstat_request_entry_refs_gc();
 
    PG_RETURN_VOID();
}

References InvalidOid, PG_GETARG_TEXT_PP, PG_RETURN_VOID, PGSTAT_CUSTOM_VAR_STATS_IDX, pgstat_drop_entry(), PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, pgstat_request_entry_refs_gc(), and text_to_cstring().

test_custom_stats_var_fetch_entry()

static PgStat_StatCustomVarEntry * test_custom_stats_var_fetch_entry ( const char *  stat_name )

static

Definition at line 147 of file test_custom_var_stats.c.

{
    /* Fetch entry by hashed name */
    return (PgStat_StatCustomVarEntry *)
        pgstat_fetch_entry(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS,
                           InvalidOid,
                           PGSTAT_CUSTOM_VAR_STATS_IDX(stat_name));
}

References InvalidOid, PGSTAT_CUSTOM_VAR_STATS_IDX, pgstat_fetch_entry(), and PGSTAT_KIND_TEST_CUSTOM_VAR_STATS.

Referenced by test_custom_stats_var_report().

test_custom_stats_var_flush_pending_cb()

static bool test_custom_stats_var_flush_pending_cb ( PgStat_EntryRef *  entry_ref, bool  nowait  )

static

Definition at line 116 of file test_custom_var_stats.c.

{
    PgStat_StatCustomVarEntry *pending_entry;
    PgStatShared_CustomVarEntry *shared_entry;
 
    pending_entry = (PgStat_StatCustomVarEntry *) entry_ref->pending;
    shared_entry = (PgStatShared_CustomVarEntry *) entry_ref->shared_stats;
 
    if (!pgstat_lock_entry(entry_ref, nowait))
        return false;
 
    /* Add pending counts to shared totals */
    shared_entry->stats.numcalls += pending_entry->numcalls;
 
    pgstat_unlock_entry(entry_ref);
 
    return true;
}

References PgStat_StatCustomVarEntry::numcalls, PgStat_EntryRef::pending, pgstat_lock_entry(), pgstat_unlock_entry(), PgStat_EntryRef::shared_stats, and PgStatShared_CustomVarEntry::stats.

test_custom_stats_var_report()

Datum test_custom_stats_var_report

(

PG_FUNCTION_ARGS

)

Definition at line 255 of file test_custom_var_stats.c.

{
    FuncCallContext *funcctx;
    char       *stat_name;
    PgStat_StatCustomVarEntry *stat_entry;
 
    if (SRF_IS_FIRSTCALL())
    {
        TupleDesc   tupdesc;
        MemoryContext oldcontext;
 
        /* Initialize SRF context */
        funcctx = SRF_FIRSTCALL_INIT();
        oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
 
        /* Get composite return type */
        if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
            elog(ERROR, "test_custom_stats_var_report: return type is not composite");
 
        funcctx->tuple_desc = BlessTupleDesc(tupdesc);
        funcctx->max_calls = 1; /* single row result */
 
        MemoryContextSwitchTo(oldcontext);
    }
 
    funcctx = SRF_PERCALL_SETUP();
 
    if (funcctx->call_cntr < funcctx->max_calls)
    {
        Datum       values[2];
        bool        nulls[2] = {false, false};
        HeapTuple   tuple;
 
        stat_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
        stat_entry = test_custom_stats_var_fetch_entry(stat_name);
 
        /* Return row only if entry exists */
        if (stat_entry)
        {
            values[0] = PointerGetDatum(cstring_to_text(stat_name));
            values[1] = Int64GetDatum(stat_entry->numcalls);
 
            tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
            SRF_RETURN_NEXT(funcctx, HeapTupleGetDatum(tuple));
        }
    }
 
    SRF_RETURN_DONE(funcctx);
}

References BlessTupleDesc(), FuncCallContext::call_cntr, cstring_to_text(), elog, ERROR, get_call_result_type(), heap_form_tuple(), HeapTupleGetDatum(), Int64GetDatum(), FuncCallContext::max_calls, MemoryContextSwitchTo(), FuncCallContext::multi_call_memory_ctx, PgStat_StatCustomVarEntry::numcalls, PG_GETARG_TEXT_PP, PointerGetDatum(), SRF_FIRSTCALL_INIT, SRF_IS_FIRSTCALL, SRF_PERCALL_SETUP, SRF_RETURN_DONE, SRF_RETURN_NEXT, test_custom_stats_var_fetch_entry(), text_to_cstring(), FuncCallContext::tuple_desc, TYPEFUNC_COMPOSITE, and values.

test_custom_stats_var_update()

Datum test_custom_stats_var_update

(

PG_FUNCTION_ARGS

)

Definition at line 209 of file test_custom_var_stats.c.

{
    char       *stat_name = text_to_cstring(PG_GETARG_TEXT_PP(0));
    PgStat_EntryRef *entry_ref;
    PgStat_StatCustomVarEntry *pending_entry;
 
    /* Get pending entry in local memory */
    entry_ref = pgstat_prep_pending_entry(PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, InvalidOid,
                                          PGSTAT_CUSTOM_VAR_STATS_IDX(stat_name), NULL);
 
    pending_entry = (PgStat_StatCustomVarEntry *) entry_ref->pending;
    pending_entry->numcalls++;
 
    PG_RETURN_VOID();
}

References InvalidOid, PgStat_StatCustomVarEntry::numcalls, PgStat_EntryRef::pending, PG_GETARG_TEXT_PP, PG_RETURN_VOID, PGSTAT_CUSTOM_VAR_STATS_IDX, PGSTAT_KIND_TEST_CUSTOM_VAR_STATS, pgstat_prep_pending_entry(), and text_to_cstring().

Variable Documentation

custom_stats

const PgStat_KindInfo custom_stats

static

Initial value:

= {
    .name = "test_custom_var_stats",
    .fixed_amount = false,      
    .write_to_file = true,      
    .track_entry_count = true,  
    .accessed_across_databases = true,  
    .shared_size = sizeof(PgStatShared_CustomVarEntry),
    .shared_data_off = offsetof(PgStatShared_CustomVarEntry, stats),
    .shared_data_len = sizeof(((PgStatShared_CustomVarEntry *) 0)->stats),
    .pending_size = sizeof(PgStat_StatCustomVarEntry),
    .flush_pending_cb = test_custom_stats_var_flush_pending_cb,
}

Definition at line 72 of file test_custom_var_stats.c.

Referenced by _PG_init().