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) 2001-2023, 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/pgstat_internal.h"
      21             : 
      22             : 
      23             : PgStat_CheckpointerStats PendingCheckpointerStats = {0};
      24             : 
      25             : 
      26             : /*
      27             :  * Report checkpointer and IO statistics
      28             :  */
      29             : void
      30       13612 : pgstat_report_checkpointer(void)
      31             : {
      32             :     /* We assume this initializes to zeroes */
      33             :     static const PgStat_CheckpointerStats all_zeroes;
      34       13612 :     PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
      35             : 
      36             :     Assert(!pgStatLocal.shmem->is_shutdown);
      37             :     pgstat_assert_is_up();
      38             : 
      39             :     /*
      40             :      * This function can be called even if nothing at all has happened. In
      41             :      * this case, avoid unnecessarily modifying the stats entry.
      42             :      */
      43       13612 :     if (memcmp(&PendingCheckpointerStats, &all_zeroes,
      44             :                sizeof(all_zeroes)) == 0)
      45       10974 :         return;
      46             : 
      47        2638 :     pgstat_begin_changecount_write(&stats_shmem->changecount);
      48             : 
      49             : #define CHECKPOINTER_ACC(fld) stats_shmem->stats.fld += PendingCheckpointerStats.fld
      50        2638 :     CHECKPOINTER_ACC(num_timed);
      51        2638 :     CHECKPOINTER_ACC(num_requested);
      52        2638 :     CHECKPOINTER_ACC(write_time);
      53        2638 :     CHECKPOINTER_ACC(sync_time);
      54        2638 :     CHECKPOINTER_ACC(buffers_written);
      55             : #undef CHECKPOINTER_ACC
      56             : 
      57        2638 :     pgstat_end_changecount_write(&stats_shmem->changecount);
      58             : 
      59             :     /*
      60             :      * Clear out the statistics buffer, so it can be re-used.
      61             :      */
      62       18466 :     MemSet(&PendingCheckpointerStats, 0, sizeof(PendingCheckpointerStats));
      63             : 
      64             :     /*
      65             :      * Report IO statistics
      66             :      */
      67        2638 :     pgstat_flush_io(false);
      68             : }
      69             : 
      70             : /*
      71             :  * pgstat_fetch_stat_checkpointer() -
      72             :  *
      73             :  * Support function for the SQL-callable pgstat* functions. Returns
      74             :  * a pointer to the checkpointer statistics struct.
      75             :  */
      76             : PgStat_CheckpointerStats *
      77          48 : pgstat_fetch_stat_checkpointer(void)
      78             : {
      79          48 :     pgstat_snapshot_fixed(PGSTAT_KIND_CHECKPOINTER);
      80             : 
      81          48 :     return &pgStatLocal.snapshot.checkpointer;
      82             : }
      83             : 
      84             : void
      85         380 : pgstat_checkpointer_reset_all_cb(TimestampTz ts)
      86             : {
      87         380 :     PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
      88             : 
      89             :     /* see explanation above PgStatShared_Checkpointer for the reset protocol */
      90         380 :     LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
      91         380 :     pgstat_copy_changecounted_stats(&stats_shmem->reset_offset,
      92         380 :                                     &stats_shmem->stats,
      93             :                                     sizeof(stats_shmem->stats),
      94             :                                     &stats_shmem->changecount);
      95         380 :     stats_shmem->stats.stat_reset_timestamp = ts;
      96         380 :     LWLockRelease(&stats_shmem->lock);
      97         380 : }
      98             : 
      99             : void
     100         968 : pgstat_checkpointer_snapshot_cb(void)
     101             : {
     102         968 :     PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
     103         968 :     PgStat_CheckpointerStats *reset_offset = &stats_shmem->reset_offset;
     104             :     PgStat_CheckpointerStats reset;
     105             : 
     106         968 :     pgstat_copy_changecounted_stats(&pgStatLocal.snapshot.checkpointer,
     107         968 :                                     &stats_shmem->stats,
     108             :                                     sizeof(stats_shmem->stats),
     109             :                                     &stats_shmem->changecount);
     110             : 
     111         968 :     LWLockAcquire(&stats_shmem->lock, LW_SHARED);
     112         968 :     memcpy(&reset, reset_offset, sizeof(stats_shmem->stats));
     113         968 :     LWLockRelease(&stats_shmem->lock);
     114             : 
     115             :     /* compensate by reset offsets */
     116             : #define CHECKPOINTER_COMP(fld) pgStatLocal.snapshot.checkpointer.fld -= reset.fld;
     117         968 :     CHECKPOINTER_COMP(num_timed);
     118         968 :     CHECKPOINTER_COMP(num_requested);
     119         968 :     CHECKPOINTER_COMP(write_time);
     120         968 :     CHECKPOINTER_COMP(sync_time);
     121         968 :     CHECKPOINTER_COMP(buffers_written);
     122             : #undef CHECKPOINTER_COMP
     123         968 : }