pgstat_wal.c File Reference

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

Include dependency graph for pgstat_wal.c:

Go to the source code of this file.

Macros
#define	WALSTAT_ACC(fld)   stats_shmem->stats.fld += PendingWalStats.fld

Functions
void	pgstat_report_wal (bool force)
PgStat_WalStats *	pgstat_fetch_stat_wal (void)
bool	pgstat_flush_wal (bool nowait)
void	pgstat_init_wal (void)
bool	pgstat_have_pending_wal (void)
void	pgstat_wal_reset_all_cb (TimestampTz ts)
void	pgstat_wal_snapshot_cb (void)

Variables
PgStat_WalStats	PendingWalStats = {0}
static WalUsage	prevWalUsage

Macro Definition Documentation

WALSTAT_ACC

#define WALSTAT_ACC

(

fld

)

stats_shmem->stats.fld += PendingWalStats.fld

Function Documentation

pgstat_fetch_stat_wal()

PgStat_WalStats* pgstat_fetch_stat_wal

(

void

)

Definition at line 53 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_flush_wal()

bool pgstat_flush_wal

(

bool

nowait

)

Definition at line 68 of file pgstat_wal.c.

{
    PgStatShared_Wal *stats_shmem = &pgStatLocal.shmem->wal;
    WalUsage    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_have_pending_wal())
        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(&diff, &pgWalUsage, &prevWalUsage);
    PendingWalStats.wal_records = diff.wal_records;
    PendingWalStats.wal_fpi = diff.wal_fpi;
    PendingWalStats.wal_bytes = diff.wal_bytes;
 
    if (!nowait)
        LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
    else if (!LWLockConditionalAcquire(&stats_shmem->lock, LW_EXCLUSIVE))
        return true;
 
#define WALSTAT_ACC(fld) stats_shmem->stats.fld += PendingWalStats.fld
    WALSTAT_ACC(wal_records);
    WALSTAT_ACC(wal_fpi);
    WALSTAT_ACC(wal_bytes);
    WALSTAT_ACC(wal_buffers_full);
    WALSTAT_ACC(wal_write);
    WALSTAT_ACC(wal_sync);
    WALSTAT_ACC(wal_write_time);
    WALSTAT_ACC(wal_sync_time);
#undef WALSTAT_ACC
 
    LWLockRelease(&stats_shmem->lock);
 
    /*
     * Save the current counters for the subsequent calculation of WAL usage.
     */
    prevWalUsage = pgWalUsage;
 
    /*
     * Clear out the statistics buffer, so it can be re-used.
     */
    MemSet(&PendingWalStats, 0, sizeof(PendingWalStats));
 
    return false;
}

References Assert(), PgStat_ShmemControl::is_shutdown, IsPostmasterEnvironment, IsUnderPostmaster, PgStatShared_Wal::lock, LW_EXCLUSIVE, LWLockAcquire(), LWLockConditionalAcquire(), LWLockRelease(), MemSet, PendingWalStats, pgstat_have_pending_wal(), pgStatLocal, pgWalUsage, prevWalUsage, PgStat_LocalState::shmem, PgStat_ShmemControl::wal, WalUsage::wal_bytes, PgStat_WalStats::wal_bytes, WalUsage::wal_fpi, PgStat_WalStats::wal_fpi, WalUsage::wal_records, PgStat_WalStats::wal_records, WALSTAT_ACC, and WalUsageAccumDiff().

Referenced by pgstat_report_stat(), and pgstat_report_wal().

pgstat_have_pending_wal()

bool pgstat_have_pending_wal

(

void

)

Definition at line 144 of file pgstat_wal.c.

{
    return pgWalUsage.wal_records != prevWalUsage.wal_records ||
        PendingWalStats.wal_write != 0 ||
        PendingWalStats.wal_sync != 0;
}

References PendingWalStats, pgWalUsage, prevWalUsage, WalUsage::wal_records, PgStat_WalStats::wal_sync, and PgStat_WalStats::wal_write.

Referenced by pgstat_flush_wal(), and pgstat_report_stat().

pgstat_init_wal()

void pgstat_init_wal

(

void

)

Definition at line 126 of file pgstat_wal.c.

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

References pgWalUsage, and prevWalUsage.

Referenced by pgstat_initialize().

pgstat_report_wal()

void pgstat_report_wal

(

bool

force

)

Definition at line 43 of file pgstat_wal.c.

{
    pgstat_flush_wal(force);
}

References pgstat_flush_wal().

Referenced by CheckpointerMain(), HandleCheckpointerInterrupts(), HandleWalWriterInterrupts(), and WalWriterMain().

pgstat_wal_reset_all_cb()

void pgstat_wal_reset_all_cb

(

TimestampTz

ts

)

Definition at line 152 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 163 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

PendingWalStats

PgStat_WalStats PendingWalStats = {0}

Definition at line 24 of file pgstat_wal.c.

Referenced by AdvanceXLInsertBuffer(), issue_xlog_fsync(), pgstat_flush_wal(), pgstat_have_pending_wal(), and XLogWrite().

prevWalUsage

WalUsage prevWalUsage

static

Definition at line 32 of file pgstat_wal.c.

Referenced by pgstat_flush_wal(), pgstat_have_pending_wal(), and pgstat_init_wal().