Age Owner TLA Line data Source code
1 : /* -------------------------------------------------------------------------
2 : *
3 : * pgstat_bgwriter.c
4 : * Implementation of bgwriter statistics.
5 : *
6 : * This file contains the implementation of bgwriter 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_bgwriter.c
15 : * -------------------------------------------------------------------------
16 : */
17 :
18 : #include "postgres.h"
19 :
20 : #include "utils/pgstat_internal.h"
21 :
22 :
23 : PgStat_BgWriterStats PendingBgWriterStats = {0};
24 :
25 :
26 : /*
27 : * Report bgwriter and IO statistics
28 : */
29 : void
368 andres 30 CBC 10438 : pgstat_report_bgwriter(void)
31 : {
32 10438 : PgStatShared_BgWriter *stats_shmem = &pgStatLocal.shmem->bgwriter;
33 : static const PgStat_BgWriterStats all_zeroes;
34 :
35 10438 : Assert(!pgStatLocal.shmem->is_shutdown);
384 36 10438 : 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 : */
368 42 10438 : if (memcmp(&PendingBgWriterStats, &all_zeroes, sizeof(all_zeroes)) == 0)
384 43 4850 : return;
44 :
368 45 5588 : pgstat_begin_changecount_write(&stats_shmem->changecount);
46 :
47 : #define BGWRITER_ACC(fld) stats_shmem->stats.fld += PendingBgWriterStats.fld
48 5588 : BGWRITER_ACC(buf_written_clean);
49 5588 : BGWRITER_ACC(maxwritten_clean);
50 5588 : BGWRITER_ACC(buf_alloc);
51 : #undef BGWRITER_ACC
52 :
53 5588 : pgstat_end_changecount_write(&stats_shmem->changecount);
54 :
55 : /*
56 : * Clear out the statistics buffer, so it can be re-used.
57 : */
384 58 27940 : MemSet(&PendingBgWriterStats, 0, sizeof(PendingBgWriterStats));
59 :
60 : /*
61 : * Report IO statistics
62 : */
60 andres 63 GNC 5588 : pgstat_flush_io(false);
64 : }
65 :
66 : /*
67 : * Support function for the SQL-callable pgstat* functions. Returns
368 andres 68 ECB : * a pointer to the bgwriter statistics struct.
69 : */
70 : PgStat_BgWriterStats *
368 andres 71 GIC 16 : pgstat_fetch_stat_bgwriter(void)
72 : {
73 16 : pgstat_snapshot_fixed(PGSTAT_KIND_BGWRITER);
74 :
75 16 : return &pgStatLocal.snapshot.bgwriter;
368 andres 76 ECB : }
77 :
78 : void
368 andres 79 GIC 442 : pgstat_bgwriter_reset_all_cb(TimestampTz ts)
368 andres 80 ECB : {
368 andres 81 GIC 442 : PgStatShared_BgWriter *stats_shmem = &pgStatLocal.shmem->bgwriter;
82 :
83 : /* see explanation above PgStatShared_BgWriter for the reset protocol */
368 andres 84 CBC 442 : LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
368 andres 85 GIC 442 : pgstat_copy_changecounted_stats(&stats_shmem->reset_offset,
368 andres 86 CBC 442 : &stats_shmem->stats,
87 : sizeof(stats_shmem->stats),
88 : &stats_shmem->changecount);
89 442 : stats_shmem->stats.stat_reset_timestamp = ts;
90 442 : LWLockRelease(&stats_shmem->lock);
91 442 : }
92 :
93 : void
94 1008 : pgstat_bgwriter_snapshot_cb(void)
368 andres 95 ECB : {
368 andres 96 CBC 1008 : PgStatShared_BgWriter *stats_shmem = &pgStatLocal.shmem->bgwriter;
368 andres 97 GIC 1008 : PgStat_BgWriterStats *reset_offset = &stats_shmem->reset_offset;
98 : PgStat_BgWriterStats reset;
368 andres 99 ECB :
368 andres 100 GIC 1008 : pgstat_copy_changecounted_stats(&pgStatLocal.snapshot.bgwriter,
368 andres 101 CBC 1008 : &stats_shmem->stats,
368 andres 102 ECB : sizeof(stats_shmem->stats),
103 : &stats_shmem->changecount);
104 :
368 andres 105 CBC 1008 : LWLockAcquire(&stats_shmem->lock, LW_SHARED);
106 1008 : memcpy(&reset, reset_offset, sizeof(stats_shmem->stats));
368 andres 107 GIC 1008 : LWLockRelease(&stats_shmem->lock);
108 :
109 : /* compensate by reset offsets */
368 andres 110 ECB : #define BGWRITER_COMP(fld) pgStatLocal.snapshot.bgwriter.fld -= reset.fld;
368 andres 111 CBC 1008 : BGWRITER_COMP(buf_written_clean);
112 1008 : BGWRITER_COMP(maxwritten_clean);
368 andres 113 GIC 1008 : BGWRITER_COMP(buf_alloc);
114 : #undef BGWRITER_COMP
115 1008 : }
|
