Line data    Source code

       1             : /* -------------------------------------------------------------------------
       2             :  *
       3             :  * pgstat_checkpointer.c
       4             :  *    Implementation of checkpoint statistics.
       5             :  *
       6             :  * This file contains the implementation of checkpoint statistics. It is kept
       7             :  * separate from pgstat.c to enforce the line between the statistics access /
       8             :  * storage implementation and the details about individual types of
       9             :  * statistics.
      10             :  *
      11             :  * Copyright (c) 2001-2025, PostgreSQL Global Development Group
      12             :  *
      13             :  * IDENTIFICATION
      14             :  *    src/backend/utils/activity/pgstat_checkpointer.c
      15             :  * -------------------------------------------------------------------------
      16             :  */
      17             : 
      18             : #include "postgres.h"
      19             : 
      20             : #include "utils/memutils.h"
      21             : #include "utils/pgstat_internal.h"
      22             : 
      23             : 
      24             : PgStat_CheckpointerStats PendingCheckpointerStats = {0};
      25             : 
      26             : 
      27             : /*
      28             :  * Report checkpointer and IO statistics
      29             :  */
      30             : void
      31       20272 : pgstat_report_checkpointer(void)
      32             : {
      33       20272 :     PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
      34             : 
      35             :     Assert(!pgStatLocal.shmem->is_shutdown);
      36             :     pgstat_assert_is_up();
      37             : 
      38             :     /*
      39             :      * This function can be called even if nothing at all has happened. In
      40             :      * this case, avoid unnecessarily modifying the stats entry.
      41             :      */
      42       20272 :     if (pg_memory_is_all_zeros(&PendingCheckpointerStats,
      43             :                                sizeof(struct PgStat_CheckpointerStats)))
      44       11428 :         return;
      45             : 
      46        8844 :     pgstat_begin_changecount_write(&stats_shmem->changecount);
      47             : 
      48             : #define CHECKPOINTER_ACC(fld) stats_shmem->stats.fld += PendingCheckpointerStats.fld
      49        8844 :     CHECKPOINTER_ACC(num_timed);
      50        8844 :     CHECKPOINTER_ACC(num_requested);
      51        8844 :     CHECKPOINTER_ACC(num_performed);
      52        8844 :     CHECKPOINTER_ACC(restartpoints_timed);
      53        8844 :     CHECKPOINTER_ACC(restartpoints_requested);
      54        8844 :     CHECKPOINTER_ACC(restartpoints_performed);
      55        8844 :     CHECKPOINTER_ACC(write_time);
      56        8844 :     CHECKPOINTER_ACC(sync_time);
      57        8844 :     CHECKPOINTER_ACC(buffers_written);
      58        8844 :     CHECKPOINTER_ACC(slru_written);
      59             : #undef CHECKPOINTER_ACC
      60             : 
      61        8844 :     pgstat_end_changecount_write(&stats_shmem->changecount);
      62             : 
      63             :     /*
      64             :      * Clear out the statistics buffer, so it can be re-used.
      65             :      */
      66      106128 :     MemSet(&PendingCheckpointerStats, 0, sizeof(PendingCheckpointerStats));
      67             : 
      68             :     /*
      69             :      * Report IO statistics
      70             :      */
      71        8844 :     pgstat_flush_io(false);
      72             : }
      73             : 
      74             : /*
      75             :  * pgstat_fetch_stat_checkpointer() -
      76             :  *
      77             :  * Support function for the SQL-callable pgstat* functions. Returns
      78             :  * a pointer to the checkpointer statistics struct.
      79             :  */
      80             : PgStat_CheckpointerStats *
      81          48 : pgstat_fetch_stat_checkpointer(void)
      82             : {
      83          48 :     pgstat_snapshot_fixed(PGSTAT_KIND_CHECKPOINTER);
      84             : 
      85          48 :     return &pgStatLocal.snapshot.checkpointer;
      86             : }
      87             : 
      88             : void
      89        2084 : pgstat_checkpointer_init_shmem_cb(void *stats)
      90             : {
      91        2084 :     PgStatShared_Checkpointer *stats_shmem = (PgStatShared_Checkpointer *) stats;
      92             : 
      93        2084 :     LWLockInitialize(&stats_shmem->lock, LWTRANCHE_PGSTATS_DATA);
      94        2084 : }
      95             : 
      96             : void
      97         454 : pgstat_checkpointer_reset_all_cb(TimestampTz ts)
      98             : {
      99         454 :     PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
     100             : 
     101             :     /* see explanation above PgStatShared_Checkpointer for the reset protocol */
     102         454 :     LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
     103         454 :     pgstat_copy_changecounted_stats(&stats_shmem->reset_offset,
     104         454 :                                     &stats_shmem->stats,
     105             :                                     sizeof(stats_shmem->stats),
     106             :                                     &stats_shmem->changecount);
     107         454 :     stats_shmem->stats.stat_reset_timestamp = ts;
     108         454 :     LWLockRelease(&stats_shmem->lock);
     109         454 : }
     110             : 
     111             : void
     112        1288 : pgstat_checkpointer_snapshot_cb(void)
     113             : {
     114        1288 :     PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
     115        1288 :     PgStat_CheckpointerStats *reset_offset = &stats_shmem->reset_offset;
     116             :     PgStat_CheckpointerStats reset;
     117             : 
     118        1288 :     pgstat_copy_changecounted_stats(&pgStatLocal.snapshot.checkpointer,
     119        1288 :                                     &stats_shmem->stats,
     120             :                                     sizeof(stats_shmem->stats),
     121             :                                     &stats_shmem->changecount);
     122             : 
     123        1288 :     LWLockAcquire(&stats_shmem->lock, LW_SHARED);
     124        1288 :     memcpy(&reset, reset_offset, sizeof(stats_shmem->stats));
     125        1288 :     LWLockRelease(&stats_shmem->lock);
     126             : 
     127             :     /* compensate by reset offsets */
     128             : #define CHECKPOINTER_COMP(fld) pgStatLocal.snapshot.checkpointer.fld -= reset.fld;
     129        1288 :     CHECKPOINTER_COMP(num_timed);
     130        1288 :     CHECKPOINTER_COMP(num_requested);
     131        1288 :     CHECKPOINTER_COMP(num_performed);
     132        1288 :     CHECKPOINTER_COMP(restartpoints_timed);
     133        1288 :     CHECKPOINTER_COMP(restartpoints_requested);
     134        1288 :     CHECKPOINTER_COMP(restartpoints_performed);
     135        1288 :     CHECKPOINTER_COMP(write_time);
     136        1288 :     CHECKPOINTER_COMP(sync_time);
     137        1288 :     CHECKPOINTER_COMP(buffers_written);
     138        1288 :     CHECKPOINTER_COMP(slru_written);
     139             : #undef CHECKPOINTER_COMP
     140        1288 : }