pgstat.h

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/* ----------
 *  pgstat.h
 *
 *  Definitions for the PostgreSQL cumulative statistics system.
 *
 *  Copyright (c) 2001-2022, PostgreSQL Global Development Group
 *
 *  src/include/pgstat.h
 * ----------
 */
#ifndef PGSTAT_H
#define PGSTAT_H
 
#include "datatype/timestamp.h"
#include "portability/instr_time.h"
#include "postmaster/pgarch.h"  /* for MAX_XFN_CHARS */
#include "utils/backend_progress.h" /* for backward compatibility */
#include "utils/backend_status.h"   /* for backward compatibility */
#include "utils/relcache.h"
#include "utils/wait_event.h"   /* for backward compatibility */
 
 
/* ----------
 * Paths for the statistics files (relative to installation's $PGDATA).
 * ----------
 */
#define PGSTAT_STAT_PERMANENT_DIRECTORY     "pg_stat"
#define PGSTAT_STAT_PERMANENT_FILENAME      "pg_stat/pgstat.stat"
#define PGSTAT_STAT_PERMANENT_TMPFILE       "pg_stat/pgstat.tmp"
 
/* Default directory to store temporary statistics data in */
#define PG_STAT_TMP_DIR     "pg_stat_tmp"
 
/* The types of statistics entries */
typedef enum PgStat_Kind
{
    /* use 0 for INVALID, to catch zero-initialized data */
    PGSTAT_KIND_INVALID = 0,
 
    /* stats for variable-numbered objects */
    PGSTAT_KIND_DATABASE,       /* database-wide statistics */
    PGSTAT_KIND_RELATION,       /* per-table statistics */
    PGSTAT_KIND_FUNCTION,       /* per-function statistics */
    PGSTAT_KIND_REPLSLOT,       /* per-slot statistics */
    PGSTAT_KIND_SUBSCRIPTION,   /* per-subscription statistics */
 
    /* stats for fixed-numbered objects */
    PGSTAT_KIND_ARCHIVER,
    PGSTAT_KIND_BGWRITER,
    PGSTAT_KIND_CHECKPOINTER,
    PGSTAT_KIND_SLRU,
    PGSTAT_KIND_WAL,
} PgStat_Kind;
 
#define PGSTAT_KIND_FIRST_VALID PGSTAT_KIND_DATABASE
#define PGSTAT_KIND_LAST PGSTAT_KIND_WAL
#define PGSTAT_NUM_KINDS (PGSTAT_KIND_LAST + 1)
 
/* Values for track_functions GUC variable --- order is significant! */
typedef enum TrackFunctionsLevel
{
    TRACK_FUNC_OFF,
    TRACK_FUNC_PL,
    TRACK_FUNC_ALL
}           TrackFunctionsLevel;
 
typedef enum PgStat_FetchConsistency
{
    PGSTAT_FETCH_CONSISTENCY_NONE,
    PGSTAT_FETCH_CONSISTENCY_CACHE,
    PGSTAT_FETCH_CONSISTENCY_SNAPSHOT,
} PgStat_FetchConsistency;
 
/* Values to track the cause of session termination */
typedef enum SessionEndType
{
    DISCONNECT_NOT_YET,         /* still active */
    DISCONNECT_NORMAL,
    DISCONNECT_CLIENT_EOF,
    DISCONNECT_FATAL,
    DISCONNECT_KILLED
} SessionEndType;
 
/* ----------
 * The data type used for counters.
 * ----------
 */
typedef int64 PgStat_Counter;
 
 
/* ------------------------------------------------------------
 * Structures kept in backend local memory while accumulating counts
 * ------------------------------------------------------------
 */
 
/* ----------
 * PgStat_FunctionCounts    The actual per-function counts kept by a backend
 *
 * This struct should contain only actual event counters, because we memcmp
 * it against zeroes to detect whether there are any pending stats.
 *
 * Note that the time counters are in instr_time format here.  We convert to
 * microseconds in PgStat_Counter format when flushing out pending statistics.
 * ----------
 */
typedef struct PgStat_FunctionCounts
{
    PgStat_Counter f_numcalls;
    instr_time  f_total_time;
    instr_time  f_self_time;
} PgStat_FunctionCounts;
 
/* ----------
 * PgStat_BackendFunctionEntry  Non-flushed function stats.
 * ----------
 */
typedef struct PgStat_BackendFunctionEntry
{
    PgStat_FunctionCounts f_counts;
} PgStat_BackendFunctionEntry;
 
/*
 * Working state needed to accumulate per-function-call timing statistics.
 */
typedef struct PgStat_FunctionCallUsage
{
    /* Link to function's hashtable entry (must still be there at exit!) */
    /* NULL means we are not tracking the current function call */
    PgStat_FunctionCounts *fs;
    /* Total time previously charged to function, as of function start */
    instr_time  save_f_total_time;
    /* Backend-wide total time as of function start */
    instr_time  save_total;
    /* system clock as of function start */
    instr_time  f_start;
} PgStat_FunctionCallUsage;
 
/* ----------
 * PgStat_BackendSubEntry   Non-flushed subscription stats.
 * ----------
 */
typedef struct PgStat_BackendSubEntry
{
    PgStat_Counter apply_error_count;
    PgStat_Counter sync_error_count;
} PgStat_BackendSubEntry;
 
/* ----------
 * PgStat_TableCounts           The actual per-table counts kept by a backend
 *
 * This struct should contain only actual event counters, because we memcmp
 * it against zeroes to detect whether there are any stats updates to apply.
 * It is a component of PgStat_TableStatus (within-backend state).
 *
 * Note: for a table, tuples_returned is the number of tuples successfully
 * fetched by heap_getnext, while tuples_fetched is the number of tuples
 * successfully fetched by heap_fetch under the control of bitmap indexscans.
 * For an index, tuples_returned is the number of index entries returned by
 * the index AM, while tuples_fetched is the number of tuples successfully
 * fetched by heap_fetch under the control of simple indexscans for this index.
 *
 * tuples_inserted/updated/deleted/hot_updated count attempted actions,
 * regardless of whether the transaction committed.  delta_live_tuples,
 * delta_dead_tuples, and changed_tuples are set depending on commit or abort.
 * Note that delta_live_tuples and delta_dead_tuples can be negative!
 * ----------
 */
typedef struct PgStat_TableCounts
{
    PgStat_Counter t_numscans;
 
    PgStat_Counter t_tuples_returned;
    PgStat_Counter t_tuples_fetched;
 
    PgStat_Counter t_tuples_inserted;
    PgStat_Counter t_tuples_updated;
    PgStat_Counter t_tuples_deleted;
    PgStat_Counter t_tuples_hot_updated;
    bool        t_truncdropped;
 
    PgStat_Counter t_delta_live_tuples;
    PgStat_Counter t_delta_dead_tuples;
    PgStat_Counter t_changed_tuples;
 
    PgStat_Counter t_blocks_fetched;
    PgStat_Counter t_blocks_hit;
} PgStat_TableCounts;
 
/* ----------
 * PgStat_TableStatus           Per-table status within a backend
 *
 * Many of the event counters are nontransactional, ie, we count events
 * in committed and aborted transactions alike.  For these, we just count
 * directly in the PgStat_TableStatus.  However, delta_live_tuples,
 * delta_dead_tuples, and changed_tuples must be derived from event counts
 * with awareness of whether the transaction or subtransaction committed or
 * aborted.  Hence, we also keep a stack of per-(sub)transaction status
 * records for every table modified in the current transaction.  At commit
 * or abort, we propagate tuples_inserted/updated/deleted up to the
 * parent subtransaction level, or out to the parent PgStat_TableStatus,
 * as appropriate.
 * ----------
 */
typedef struct PgStat_TableStatus
{
    Oid         t_id;           /* table's OID */
    bool        t_shared;       /* is it a shared catalog? */
    struct PgStat_TableXactStatus *trans;   /* lowest subxact's counts */
    PgStat_TableCounts t_counts;    /* event counts to be sent */
    Relation    relation;       /* rel that is using this entry */
} PgStat_TableStatus;
 
/* ----------
 * PgStat_TableXactStatus       Per-table, per-subtransaction status
 * ----------
 */
typedef struct PgStat_TableXactStatus
{
    PgStat_Counter tuples_inserted; /* tuples inserted in (sub)xact */
    PgStat_Counter tuples_updated;  /* tuples updated in (sub)xact */
    PgStat_Counter tuples_deleted;  /* tuples deleted in (sub)xact */
    bool        truncdropped;   /* relation truncated/dropped in this
                                 * (sub)xact */
    /* tuples i/u/d prior to truncate/drop */
    PgStat_Counter inserted_pre_truncdrop;
    PgStat_Counter updated_pre_truncdrop;
    PgStat_Counter deleted_pre_truncdrop;
    int         nest_level;     /* subtransaction nest level */
    /* links to other structs for same relation: */
    struct PgStat_TableXactStatus *upper;   /* next higher subxact if any */
    PgStat_TableStatus *parent; /* per-table status */
    /* structs of same subxact level are linked here: */
    struct PgStat_TableXactStatus *next;    /* next of same subxact */
} PgStat_TableXactStatus;
 
 
/* ------------------------------------------------------------
 * Data structures on disk and in shared memory follow
 *
 * PGSTAT_FILE_FORMAT_ID should be changed whenever any of these
 * data structures change.
 * ------------------------------------------------------------
 */
 
#define PGSTAT_FILE_FORMAT_ID   0x01A5BCA7
 
typedef struct PgStat_ArchiverStats
{
    PgStat_Counter archived_count;  /* archival successes */
    char        last_archived_wal[MAX_XFN_CHARS + 1];   /* last WAL file
                                                         * archived */
    TimestampTz last_archived_timestamp;    /* last archival success time */
    PgStat_Counter failed_count;    /* failed archival attempts */
    char        last_failed_wal[MAX_XFN_CHARS + 1]; /* WAL file involved in
                                                     * last failure */
    TimestampTz last_failed_timestamp;  /* last archival failure time */
    TimestampTz stat_reset_timestamp;
} PgStat_ArchiverStats;
 
typedef struct PgStat_BgWriterStats
{
    PgStat_Counter buf_written_clean;
    PgStat_Counter maxwritten_clean;
    PgStat_Counter buf_alloc;
    TimestampTz stat_reset_timestamp;
} PgStat_BgWriterStats;
 
typedef struct PgStat_CheckpointerStats
{
    PgStat_Counter timed_checkpoints;
    PgStat_Counter requested_checkpoints;
    PgStat_Counter checkpoint_write_time;   /* times in milliseconds */
    PgStat_Counter checkpoint_sync_time;
    PgStat_Counter buf_written_checkpoints;
    PgStat_Counter buf_written_backend;
    PgStat_Counter buf_fsync_backend;
} PgStat_CheckpointerStats;
 
typedef struct PgStat_StatDBEntry
{
    PgStat_Counter n_xact_commit;
    PgStat_Counter n_xact_rollback;
    PgStat_Counter n_blocks_fetched;
    PgStat_Counter n_blocks_hit;
    PgStat_Counter n_tuples_returned;
    PgStat_Counter n_tuples_fetched;
    PgStat_Counter n_tuples_inserted;
    PgStat_Counter n_tuples_updated;
    PgStat_Counter n_tuples_deleted;
    TimestampTz last_autovac_time;
    PgStat_Counter n_conflict_tablespace;
    PgStat_Counter n_conflict_lock;
    PgStat_Counter n_conflict_snapshot;
    PgStat_Counter n_conflict_bufferpin;
    PgStat_Counter n_conflict_startup_deadlock;
    PgStat_Counter n_temp_files;
    PgStat_Counter n_temp_bytes;
    PgStat_Counter n_deadlocks;
    PgStat_Counter n_checksum_failures;
    TimestampTz last_checksum_failure;
    PgStat_Counter n_block_read_time;   /* times in microseconds */
    PgStat_Counter n_block_write_time;
    PgStat_Counter n_sessions;
    PgStat_Counter total_session_time;
    PgStat_Counter total_active_time;
    PgStat_Counter total_idle_in_xact_time;
    PgStat_Counter n_sessions_abandoned;
    PgStat_Counter n_sessions_fatal;
    PgStat_Counter n_sessions_killed;
 
    TimestampTz stat_reset_timestamp;
} PgStat_StatDBEntry;
 
typedef struct PgStat_StatFuncEntry
{
    PgStat_Counter f_numcalls;
 
    PgStat_Counter f_total_time;    /* times in microseconds */
    PgStat_Counter f_self_time;
} PgStat_StatFuncEntry;
 
typedef struct PgStat_StatReplSlotEntry
{
    NameData    slotname;
    PgStat_Counter spill_txns;
    PgStat_Counter spill_count;
    PgStat_Counter spill_bytes;
    PgStat_Counter stream_txns;
    PgStat_Counter stream_count;
    PgStat_Counter stream_bytes;
    PgStat_Counter total_txns;
    PgStat_Counter total_bytes;
    TimestampTz stat_reset_timestamp;
} PgStat_StatReplSlotEntry;
 
typedef struct PgStat_SLRUStats
{
    PgStat_Counter blocks_zeroed;
    PgStat_Counter blocks_hit;
    PgStat_Counter blocks_read;
    PgStat_Counter blocks_written;
    PgStat_Counter blocks_exists;
    PgStat_Counter flush;
    PgStat_Counter truncate;
    TimestampTz stat_reset_timestamp;
} PgStat_SLRUStats;
 
typedef struct PgStat_StatSubEntry
{
    PgStat_Counter apply_error_count;
    PgStat_Counter sync_error_count;
    TimestampTz stat_reset_timestamp;
} PgStat_StatSubEntry;
 
typedef struct PgStat_StatTabEntry
{
    PgStat_Counter numscans;
 
    PgStat_Counter tuples_returned;
    PgStat_Counter tuples_fetched;
 
    PgStat_Counter tuples_inserted;
    PgStat_Counter tuples_updated;
    PgStat_Counter tuples_deleted;
    PgStat_Counter tuples_hot_updated;
 
    PgStat_Counter n_live_tuples;
    PgStat_Counter n_dead_tuples;
    PgStat_Counter changes_since_analyze;
    PgStat_Counter inserts_since_vacuum;
 
    PgStat_Counter blocks_fetched;
    PgStat_Counter blocks_hit;
 
    TimestampTz vacuum_timestamp;   /* user initiated vacuum */
    PgStat_Counter vacuum_count;
    TimestampTz autovac_vacuum_timestamp;   /* autovacuum initiated */
    PgStat_Counter autovac_vacuum_count;
    TimestampTz analyze_timestamp;  /* user initiated */
    PgStat_Counter analyze_count;
    TimestampTz autovac_analyze_timestamp;  /* autovacuum initiated */
    PgStat_Counter autovac_analyze_count;
} PgStat_StatTabEntry;
 
typedef struct PgStat_WalStats
{
    PgStat_Counter wal_records;
    PgStat_Counter wal_fpi;
    uint64      wal_bytes;
    PgStat_Counter wal_buffers_full;
    PgStat_Counter wal_write;
    PgStat_Counter wal_sync;
    PgStat_Counter wal_write_time;
    PgStat_Counter wal_sync_time;
    TimestampTz stat_reset_timestamp;
} PgStat_WalStats;
 
 
/*
 * Functions in pgstat.c
 */
 
/* functions called from postmaster */
extern Size StatsShmemSize(void);
extern void StatsShmemInit(void);
 
/* Functions called during server startup / shutdown */
extern void pgstat_restore_stats(void);
extern void pgstat_discard_stats(void);
extern void pgstat_before_server_shutdown(int code, Datum arg);
 
/* Functions for backend initialization */
extern void pgstat_initialize(void);
 
/* Functions called from backends */
extern long pgstat_report_stat(bool force);
extern void pgstat_force_next_flush(void);
 
extern void pgstat_reset_counters(void);
extern void pgstat_reset(PgStat_Kind kind, Oid dboid, Oid objectid);
extern void pgstat_reset_of_kind(PgStat_Kind kind);
 
/* stats accessors */
extern void pgstat_clear_snapshot(void);
extern TimestampTz pgstat_get_stat_snapshot_timestamp(bool *have_snapshot);
 
/* helpers */
extern PgStat_Kind pgstat_get_kind_from_str(char *kind_str);
extern bool pgstat_have_entry(PgStat_Kind kind, Oid dboid, Oid objoid);
 
 
/*
 * Functions in pgstat_archiver.c
 */
 
extern void pgstat_report_archiver(const char *xlog, bool failed);
extern PgStat_ArchiverStats *pgstat_fetch_stat_archiver(void);
 
 
/*
 * Functions in pgstat_bgwriter.c
 */
 
extern void pgstat_report_bgwriter(void);
extern PgStat_BgWriterStats *pgstat_fetch_stat_bgwriter(void);
 
 
/*
 * Functions in pgstat_checkpointer.c
 */
 
extern void pgstat_report_checkpointer(void);
extern PgStat_CheckpointerStats *pgstat_fetch_stat_checkpointer(void);
 
 
/*
 * Functions in pgstat_database.c
 */
 
extern void pgstat_drop_database(Oid databaseid);
extern void pgstat_report_autovac(Oid dboid);
extern void pgstat_report_recovery_conflict(int reason);
extern void pgstat_report_deadlock(void);
extern void pgstat_report_checksum_failures_in_db(Oid dboid, int failurecount);
extern void pgstat_report_checksum_failure(void);
extern void pgstat_report_connect(Oid dboid);
 
#define pgstat_count_buffer_read_time(n)                            \
    (pgStatBlockReadTime += (n))
#define pgstat_count_buffer_write_time(n)                           \
    (pgStatBlockWriteTime += (n))
#define pgstat_count_conn_active_time(n)                            \
    (pgStatActiveTime += (n))
#define pgstat_count_conn_txn_idle_time(n)                          \
    (pgStatTransactionIdleTime += (n))
 
extern PgStat_StatDBEntry *pgstat_fetch_stat_dbentry(Oid dbid);
 
/*
 * Functions in pgstat_function.c
 */
 
extern void pgstat_create_function(Oid proid);
extern void pgstat_drop_function(Oid proid);
 
struct FunctionCallInfoBaseData;
extern void pgstat_init_function_usage(struct FunctionCallInfoBaseData *fcinfo,
                                       PgStat_FunctionCallUsage *fcu);
extern void pgstat_end_function_usage(PgStat_FunctionCallUsage *fcu,
                                      bool finalize);
 
extern PgStat_StatFuncEntry *pgstat_fetch_stat_funcentry(Oid funcid);
extern PgStat_BackendFunctionEntry *find_funcstat_entry(Oid func_id);
 
 
/*
 * Functions in pgstat_relation.c
 */
 
extern void pgstat_create_relation(Relation rel);
extern void pgstat_drop_relation(Relation rel);
extern void pgstat_copy_relation_stats(Relation dstrel, Relation srcrel);
 
extern void pgstat_init_relation(Relation rel);
extern void pgstat_assoc_relation(Relation rel);
extern void pgstat_unlink_relation(Relation rel);
 
extern void pgstat_report_vacuum(Oid tableoid, bool shared,
                                 PgStat_Counter livetuples, PgStat_Counter deadtuples);
extern void pgstat_report_analyze(Relation rel,
                                  PgStat_Counter livetuples, PgStat_Counter deadtuples,
                                  bool resetcounter);
 
/*
 * If stats are enabled, but pending data hasn't been prepared yet, call
 * pgstat_assoc_relation() to do so. See its comment for why this is done
 * separately from pgstat_init_relation().
 */
#define pgstat_should_count_relation(rel)                           \
    (likely((rel)->pgstat_info != NULL) ? true :                    \
     ((rel)->pgstat_enabled ? pgstat_assoc_relation(rel), true : false))
 
/* nontransactional event counts are simple enough to inline */
 
#define pgstat_count_heap_scan(rel)                                 \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_numscans++;              \
    } while (0)
#define pgstat_count_heap_getnext(rel)                              \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_tuples_returned++;       \
    } while (0)
#define pgstat_count_heap_fetch(rel)                                \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_tuples_fetched++;        \
    } while (0)
#define pgstat_count_index_scan(rel)                                \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_numscans++;              \
    } while (0)
#define pgstat_count_index_tuples(rel, n)                           \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_tuples_returned += (n);  \
    } while (0)
#define pgstat_count_buffer_read(rel)                               \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_blocks_fetched++;        \
    } while (0)
#define pgstat_count_buffer_hit(rel)                                \
    do {                                                            \
        if (pgstat_should_count_relation(rel))                      \
            (rel)->pgstat_info->t_counts.t_blocks_hit++;            \
    } while (0)
 
extern void pgstat_count_heap_insert(Relation rel, PgStat_Counter n);
extern void pgstat_count_heap_update(Relation rel, bool hot);
extern void pgstat_count_heap_delete(Relation rel);
extern void pgstat_count_truncate(Relation rel);
extern void pgstat_update_heap_dead_tuples(Relation rel, int delta);
 
extern void pgstat_twophase_postcommit(TransactionId xid, uint16 info,
                                       void *recdata, uint32 len);
extern void pgstat_twophase_postabort(TransactionId xid, uint16 info,
                                      void *recdata, uint32 len);
 
extern PgStat_StatTabEntry *pgstat_fetch_stat_tabentry(Oid relid);
extern PgStat_StatTabEntry *pgstat_fetch_stat_tabentry_ext(bool shared,
                                                           Oid relid);
extern PgStat_TableStatus *find_tabstat_entry(Oid rel_id);
 
 
/*
 * Functions in pgstat_replslot.c
 */
 
extern void pgstat_reset_replslot(const char *name);
struct ReplicationSlot;
extern void pgstat_report_replslot(struct ReplicationSlot *slot, const PgStat_StatReplSlotEntry *repSlotStat);
extern void pgstat_create_replslot(struct ReplicationSlot *slot);
extern void pgstat_acquire_replslot(struct ReplicationSlot *slot);
extern void pgstat_drop_replslot(struct ReplicationSlot *slot);
extern PgStat_StatReplSlotEntry *pgstat_fetch_replslot(NameData slotname);
 
 
/*
 * Functions in pgstat_slru.c
 */
 
extern void pgstat_reset_slru(const char *);
extern void pgstat_count_slru_page_zeroed(int slru_idx);
extern void pgstat_count_slru_page_hit(int slru_idx);
extern void pgstat_count_slru_page_read(int slru_idx);
extern void pgstat_count_slru_page_written(int slru_idx);
extern void pgstat_count_slru_page_exists(int slru_idx);
extern void pgstat_count_slru_flush(int slru_idx);
extern void pgstat_count_slru_truncate(int slru_idx);
extern const char *pgstat_get_slru_name(int slru_idx);
extern int  pgstat_get_slru_index(const char *name);
extern PgStat_SLRUStats *pgstat_fetch_slru(void);
 
 
/*
 * Functions in pgstat_subscription.c
 */
 
extern void pgstat_report_subscription_error(Oid subid, bool is_apply_error);
extern void pgstat_create_subscription(Oid subid);
extern void pgstat_drop_subscription(Oid subid);
extern PgStat_StatSubEntry *pgstat_fetch_stat_subscription(Oid subid);
 
 
/*
 * Functions in pgstat_xact.c
 */
 
extern void AtEOXact_PgStat(bool isCommit, bool parallel);
extern void AtEOSubXact_PgStat(bool isCommit, int nestDepth);
extern void AtPrepare_PgStat(void);
extern void PostPrepare_PgStat(void);
struct xl_xact_stats_item;
extern int  pgstat_get_transactional_drops(bool isCommit, struct xl_xact_stats_item **items);
extern void pgstat_execute_transactional_drops(int ndrops, struct xl_xact_stats_item *items, bool is_redo);
 
 
/*
 * Functions in pgstat_wal.c
 */
 
extern void pgstat_report_wal(bool force);
extern PgStat_WalStats *pgstat_fetch_stat_wal(void);
 
 
/*
 * Variables in pgstat.c
 */
 
/* GUC parameters */
extern PGDLLIMPORT bool pgstat_track_counts;
extern PGDLLIMPORT int pgstat_track_functions;
extern PGDLLIMPORT int pgstat_fetch_consistency;
 
 
/*
 * Variables in pgstat_bgwriter.c
 */
 
/* updated directly by bgwriter and bufmgr */
extern PGDLLIMPORT PgStat_BgWriterStats PendingBgWriterStats;
 
 
/*
 * Variables in pgstat_checkpointer.c
 */
 
/*
 * Checkpointer statistics counters are updated directly by checkpointer and
 * bufmgr.
 */
extern PGDLLIMPORT PgStat_CheckpointerStats PendingCheckpointerStats;
 
 
/*
 * Variables in pgstat_database.c
 */
 
/* Updated by pgstat_count_buffer_*_time macros */
extern PGDLLIMPORT PgStat_Counter pgStatBlockReadTime;
extern PGDLLIMPORT PgStat_Counter pgStatBlockWriteTime;
 
/*
 * Updated by pgstat_count_conn_*_time macros, called by
 * pgstat_report_activity().
 */
extern PGDLLIMPORT PgStat_Counter pgStatActiveTime;
extern PGDLLIMPORT PgStat_Counter pgStatTransactionIdleTime;
 
/* updated by the traffic cop and in errfinish() */
extern PGDLLIMPORT SessionEndType pgStatSessionEndCause;
 
 
/*
 * Variables in pgstat_wal.c
 */
 
/* updated directly by backends and background processes */
extern PGDLLIMPORT PgStat_WalStats PendingWalStats;
 
 
#endif                          /* PGSTAT_H */