pgstat_wal.c File Reference

#include "postgres.h"
#include "executor/instrument.h"
#include "utils/pgstat_internal.h"

Include dependency graph for pgstat_wal.c:

Go to the source code of this file.

Macros
#define	WALSTAT_ACC(fld, var_to_add)    (stats_shmem->stats.wal_counters.fld += var_to_add.fld)

Functions
void	pgstat_report_wal (bool force)
PgStat_WalStats *	pgstat_fetch_stat_wal (void)
bool	pgstat_wal_flush_cb (bool nowait)
void	pgstat_wal_init_backend_cb (void)
bool	pgstat_wal_have_pending_cb (void)
void	pgstat_wal_init_shmem_cb (void *stats)
void	pgstat_wal_reset_all_cb (TimestampTz ts)
void	pgstat_wal_snapshot_cb (void)

Variables
static WalUsage	prevWalUsage

Macro Definition Documentation

WALSTAT_ACC

#define WALSTAT_ACC	(		fld,
			var_to_add
	)		(stats_shmem->stats.wal_counters.fld += var_to_add.fld)

Function Documentation

pgstat_fetch_stat_wal()

PgStat_WalStats * pgstat_fetch_stat_wal

(

void

)

Definition at line 67 of file pgstat_wal.c.

{
    pgstat_snapshot_fixed(PGSTAT_KIND_WAL);
 
    return &pgStatLocal.snapshot.wal;
}

References PGSTAT_KIND_WAL, pgstat_snapshot_fixed(), pgStatLocal, PgStat_LocalState::snapshot, and PgStat_Snapshot::wal.

Referenced by pg_stat_get_wal().

pgstat_report_wal()

void pgstat_report_wal

(

bool

force

)

Definition at line 46 of file pgstat_wal.c.

{
    bool        nowait;
 
    /* like in pgstat.c, don't wait for lock acquisition when !force */
    nowait = !force;
 
    /* flush wal stats */
    (void) pgstat_wal_flush_cb(nowait);
    pgstat_flush_backend(nowait, PGSTAT_BACKEND_FLUSH_WAL);
 
    /* flush IO stats */
    pgstat_flush_io(nowait);
    (void) pgstat_flush_backend(nowait, PGSTAT_BACKEND_FLUSH_IO);
}

References PGSTAT_BACKEND_FLUSH_IO, PGSTAT_BACKEND_FLUSH_WAL, pgstat_flush_backend(), pgstat_flush_io(), and pgstat_wal_flush_cb().

Referenced by BackgroundWriterMain(), CheckpointerMain(), summarizer_wait_for_wal(), WalReceiverMain(), and WalWriterMain().

pgstat_wal_flush_cb()

bool pgstat_wal_flush_cb

(

bool

nowait

)

Definition at line 82 of file pgstat_wal.c.

{
    PgStatShared_Wal *stats_shmem = &pgStatLocal.shmem->wal;
    WalUsage    wal_usage_diff = {0};
 
    Assert(IsUnderPostmaster || !IsPostmasterEnvironment);
    Assert(pgStatLocal.shmem != NULL &&
           !pgStatLocal.shmem->is_shutdown);
 
    /*
     * This function can be called even if nothing at all has happened. Avoid
     * taking lock for nothing in that case.
     */
    if (!pgstat_wal_have_pending_cb())
        return false;
 
    /*
     * We don't update the WAL usage portion of the local WalStats elsewhere.
     * Calculate how much WAL usage counters were increased by subtracting the
     * previous counters from the current ones.
     */
    WalUsageAccumDiff(&wal_usage_diff, &pgWalUsage, &prevWalUsage);
 
    if (!nowait)
        LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
    else if (!LWLockConditionalAcquire(&stats_shmem->lock, LW_EXCLUSIVE))
        return true;
 
#define WALSTAT_ACC(fld, var_to_add) \
    (stats_shmem->stats.wal_counters.fld += var_to_add.fld)
    WALSTAT_ACC(wal_records, wal_usage_diff);
    WALSTAT_ACC(wal_fpi, wal_usage_diff);
    WALSTAT_ACC(wal_bytes, wal_usage_diff);
    WALSTAT_ACC(wal_buffers_full, wal_usage_diff);
#undef WALSTAT_ACC
 
    LWLockRelease(&stats_shmem->lock);
 
    /*
     * Save the current counters for the subsequent calculation of WAL usage.
     */
    prevWalUsage = pgWalUsage;
 
    return false;
}

References Assert(), PgStat_ShmemControl::is_shutdown, IsPostmasterEnvironment, IsUnderPostmaster, PgStatShared_Wal::lock, LW_EXCLUSIVE, LWLockAcquire(), LWLockConditionalAcquire(), LWLockRelease(), pgstat_wal_have_pending_cb(), pgStatLocal, pgWalUsage, prevWalUsage, PgStat_LocalState::shmem, PgStat_ShmemControl::wal, WALSTAT_ACC, and WalUsageAccumDiff().

Referenced by pgstat_report_wal().

pgstat_wal_have_pending_cb()

bool pgstat_wal_have_pending_cb

(

void

)

Definition at line 143 of file pgstat_wal.c.

{
    return pgWalUsage.wal_records != prevWalUsage.wal_records;
}

References pgWalUsage, prevWalUsage, and WalUsage::wal_records.

Referenced by pgstat_wal_flush_cb().

pgstat_wal_init_backend_cb()

void pgstat_wal_init_backend_cb

(

void

)

Definition at line 129 of file pgstat_wal.c.

{
    /*
     * Initialize prevWalUsage with pgWalUsage so that pgstat_wal_flush_cb()
     * can calculate how much pgWalUsage counters are increased by subtracting
     * prevWalUsage from pgWalUsage.
     */
    prevWalUsage = pgWalUsage;
}

References pgWalUsage, and prevWalUsage.

pgstat_wal_init_shmem_cb()

void pgstat_wal_init_shmem_cb

(

void *

stats

)

Definition at line 149 of file pgstat_wal.c.

{
    PgStatShared_Wal *stats_shmem = (PgStatShared_Wal *) stats;
 
    LWLockInitialize(&stats_shmem->lock, LWTRANCHE_PGSTATS_DATA);
}

References PgStatShared_Wal::lock, LWLockInitialize(), and LWTRANCHE_PGSTATS_DATA.

pgstat_wal_reset_all_cb()

void pgstat_wal_reset_all_cb

(

TimestampTz

ts

)

Definition at line 157 of file pgstat_wal.c.

{
    PgStatShared_Wal *stats_shmem = &pgStatLocal.shmem->wal;
 
    LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
    memset(&stats_shmem->stats, 0, sizeof(stats_shmem->stats));
    stats_shmem->stats.stat_reset_timestamp = ts;
    LWLockRelease(&stats_shmem->lock);
}

References PgStatShared_Wal::lock, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), pgStatLocal, PgStat_LocalState::shmem, PgStat_WalStats::stat_reset_timestamp, PgStatShared_Wal::stats, and PgStat_ShmemControl::wal.

pgstat_wal_snapshot_cb()

void pgstat_wal_snapshot_cb

(

void

)

Definition at line 168 of file pgstat_wal.c.

{
    PgStatShared_Wal *stats_shmem = &pgStatLocal.shmem->wal;
 
    LWLockAcquire(&stats_shmem->lock, LW_SHARED);
    memcpy(&pgStatLocal.snapshot.wal, &stats_shmem->stats,
           sizeof(pgStatLocal.snapshot.wal));
    LWLockRelease(&stats_shmem->lock);
}

References PgStatShared_Wal::lock, LW_SHARED, LWLockAcquire(), LWLockRelease(), pgStatLocal, PgStat_LocalState::shmem, PgStat_LocalState::snapshot, PgStatShared_Wal::stats, PgStat_ShmemControl::wal, and PgStat_Snapshot::wal.

Variable Documentation

prevWalUsage

WalUsage prevWalUsage

static

Definition at line 30 of file pgstat_wal.c.

Referenced by pgstat_wal_flush_cb(), pgstat_wal_have_pending_cb(), and pgstat_wal_init_backend_cb().