pgstat_bgwriter.c File Reference

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

Include dependency graph for pgstat_bgwriter.c:

Go to the source code of this file.

Macros
#define	BGWRITER_ACC(fld)   stats_shmem->stats.fld += PendingBgWriterStats.fld
#define	BGWRITER_COMP(fld)   pgStatLocal.snapshot.bgwriter.fld -= reset.fld;

Functions
void	pgstat_report_bgwriter (void)
PgStat_BgWriterStats *	pgstat_fetch_stat_bgwriter (void)
void	pgstat_bgwriter_init_shmem_cb (void *stats)
void	pgstat_bgwriter_reset_all_cb (TimestampTz ts)
void	pgstat_bgwriter_snapshot_cb (void)

Variables
PgStat_BgWriterStats	PendingBgWriterStats = {0}

Macro Definition Documentation

BGWRITER_ACC

#define BGWRITER_ACC

(

fld

)

stats_shmem->stats.fld += PendingBgWriterStats.fld

BGWRITER_COMP

#define BGWRITER_COMP

(

fld

)

pgStatLocal.snapshot.bgwriter.fld -= reset.fld;

Function Documentation

pgstat_bgwriter_init_shmem_cb()

void pgstat_bgwriter_init_shmem_cb

(

void *

stats

)

Definition at line 79 of file pgstat_bgwriter.c.

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

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

pgstat_bgwriter_reset_all_cb()

void pgstat_bgwriter_reset_all_cb

(

TimestampTz

ts

)

Definition at line 87 of file pgstat_bgwriter.c.

{
    PgStatShared_BgWriter *stats_shmem = &pgStatLocal.shmem->bgwriter;
 
    /* see explanation above PgStatShared_BgWriter for the reset protocol */
    LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
    pgstat_copy_changecounted_stats(&stats_shmem->reset_offset,
                                    &stats_shmem->stats,
                                    sizeof(stats_shmem->stats),
                                    &stats_shmem->changecount);
    stats_shmem->stats.stat_reset_timestamp = ts;
    LWLockRelease(&stats_shmem->lock);
}

References PgStat_ShmemControl::bgwriter, PgStatShared_BgWriter::changecount, PgStatShared_BgWriter::lock, LW_EXCLUSIVE, LWLockAcquire(), LWLockRelease(), pgstat_copy_changecounted_stats(), pgStatLocal, PgStatShared_BgWriter::reset_offset, PgStat_LocalState::shmem, PgStat_BgWriterStats::stat_reset_timestamp, and PgStatShared_BgWriter::stats.

pgstat_bgwriter_snapshot_cb()

void pgstat_bgwriter_snapshot_cb

(

void

)

Definition at line 102 of file pgstat_bgwriter.c.

{
    PgStatShared_BgWriter *stats_shmem = &pgStatLocal.shmem->bgwriter;
    PgStat_BgWriterStats *reset_offset = &stats_shmem->reset_offset;
    PgStat_BgWriterStats reset;
 
    pgstat_copy_changecounted_stats(&pgStatLocal.snapshot.bgwriter,
                                    &stats_shmem->stats,
                                    sizeof(stats_shmem->stats),
                                    &stats_shmem->changecount);
 
    LWLockAcquire(&stats_shmem->lock, LW_SHARED);
    memcpy(&reset, reset_offset, sizeof(stats_shmem->stats));
    LWLockRelease(&stats_shmem->lock);
 
    /* compensate by reset offsets */
#define BGWRITER_COMP(fld) pgStatLocal.snapshot.bgwriter.fld -= reset.fld;
    BGWRITER_COMP(buf_written_clean);
    BGWRITER_COMP(maxwritten_clean);
    BGWRITER_COMP(buf_alloc);
#undef BGWRITER_COMP
}

References PgStat_ShmemControl::bgwriter, PgStat_Snapshot::bgwriter, BGWRITER_COMP, PgStatShared_BgWriter::changecount, PgStatShared_BgWriter::lock, LW_SHARED, LWLockAcquire(), LWLockRelease(), pgstat_copy_changecounted_stats(), pgStatLocal, reset(), PgStatShared_BgWriter::reset_offset, PgStat_LocalState::shmem, PgStat_LocalState::snapshot, and PgStatShared_BgWriter::stats.

pgstat_fetch_stat_bgwriter()

PgStat_BgWriterStats* pgstat_fetch_stat_bgwriter

(

void

)

Definition at line 71 of file pgstat_bgwriter.c.

{
    pgstat_snapshot_fixed(PGSTAT_KIND_BGWRITER);
 
    return &pgStatLocal.snapshot.bgwriter;
}

References PgStat_Snapshot::bgwriter, PGSTAT_KIND_BGWRITER, pgstat_snapshot_fixed(), pgStatLocal, and PgStat_LocalState::snapshot.

Referenced by pg_stat_get_bgwriter_buf_written_clean(), pg_stat_get_bgwriter_maxwritten_clean(), pg_stat_get_bgwriter_stat_reset_time(), and pg_stat_get_buf_alloc().

pgstat_report_bgwriter()

void pgstat_report_bgwriter

(

void

)

Definition at line 30 of file pgstat_bgwriter.c.

{
    PgStatShared_BgWriter *stats_shmem = &pgStatLocal.shmem->bgwriter;
    static const PgStat_BgWriterStats all_zeroes;
 
    Assert(!pgStatLocal.shmem->is_shutdown);
    pgstat_assert_is_up();
 
    /*
     * This function can be called even if nothing at all has happened. In
     * this case, avoid unnecessarily modifying the stats entry.
     */
    if (memcmp(&PendingBgWriterStats, &all_zeroes, sizeof(all_zeroes)) == 0)
        return;
 
    pgstat_begin_changecount_write(&stats_shmem->changecount);
 
#define BGWRITER_ACC(fld) stats_shmem->stats.fld += PendingBgWriterStats.fld
    BGWRITER_ACC(buf_written_clean);
    BGWRITER_ACC(maxwritten_clean);
    BGWRITER_ACC(buf_alloc);
#undef BGWRITER_ACC
 
    pgstat_end_changecount_write(&stats_shmem->changecount);
 
    /*
     * Clear out the statistics buffer, so it can be re-used.
     */
    MemSet(&PendingBgWriterStats, 0, sizeof(PendingBgWriterStats));
 
    /*
     * Report IO statistics
     */
    pgstat_flush_io(false);
}

References Assert, PgStat_ShmemControl::bgwriter, BGWRITER_ACC, PgStatShared_BgWriter::changecount, PgStat_ShmemControl::is_shutdown, MemSet, PendingBgWriterStats, pgstat_assert_is_up, pgstat_begin_changecount_write(), pgstat_end_changecount_write(), pgstat_flush_io(), pgStatLocal, and PgStat_LocalState::shmem.

Referenced by BackgroundWriterMain().

Variable Documentation

PendingBgWriterStats

PgStat_BgWriterStats PendingBgWriterStats = {0}

Definition at line 23 of file pgstat_bgwriter.c.

Referenced by BgBufferSync(), and pgstat_report_bgwriter().