PostgreSQL Source Code: src/backend/utils/activity/pgstat_checkpointer.c Source File

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pgstat_checkpointer.c
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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 */
30void
31 pgstat_report_checkpointer(void)
32{
33 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 if (pg_memory_is_all_zeros(&PendingCheckpointerStats,
43 sizeof(struct PgStat_CheckpointerStats)))
44 return;
45
46 pgstat_begin_changecount_write(&stats_shmem->changecount);
47
48#define CHECKPOINTER_ACC(fld) stats_shmem->stats.fld += PendingCheckpointerStats.fld
49 CHECKPOINTER_ACC(num_timed);
50 CHECKPOINTER_ACC(num_requested);
51 CHECKPOINTER_ACC(num_performed);
52 CHECKPOINTER_ACC(restartpoints_timed);
53 CHECKPOINTER_ACC(restartpoints_requested);
54 CHECKPOINTER_ACC(restartpoints_performed);
55 CHECKPOINTER_ACC(write_time);
56 CHECKPOINTER_ACC(sync_time);
57 CHECKPOINTER_ACC(buffers_written);
58 CHECKPOINTER_ACC(slru_written);
59#undef CHECKPOINTER_ACC
60
61 pgstat_end_changecount_write(&stats_shmem->changecount);
62
63 /*
64 * Clear out the statistics buffer, so it can be re-used.
65 */
66 MemSet(&PendingCheckpointerStats, 0, sizeof(PendingCheckpointerStats));
67
68 /*
69 * Report IO statistics
70 */
71 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 */
80PgStat_CheckpointerStats *
81 pgstat_fetch_stat_checkpointer(void)
82{
83 pgstat_snapshot_fixed(PGSTAT_KIND_CHECKPOINTER);
84
85 return &pgStatLocal.snapshot.checkpointer;
86}
87
88void
89 pgstat_checkpointer_init_shmem_cb(void *stats)
90{
91 PgStatShared_Checkpointer *stats_shmem = (PgStatShared_Checkpointer *) stats;
92
93 LWLockInitialize(&stats_shmem->lock, LWTRANCHE_PGSTATS_DATA);
94}
95
96void
97 pgstat_checkpointer_reset_all_cb(TimestampTz ts)
98{
99 PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
100
101 /* see explanation above PgStatShared_Checkpointer for the reset protocol */
102 LWLockAcquire(&stats_shmem->lock, LW_EXCLUSIVE);
103 pgstat_copy_changecounted_stats(&stats_shmem->reset_offset,
104 &stats_shmem->stats,
105 sizeof(stats_shmem->stats),
106 &stats_shmem->changecount);
107 stats_shmem->stats.stat_reset_timestamp = ts;
108 LWLockRelease(&stats_shmem->lock);
109}
110
111void
112 pgstat_checkpointer_snapshot_cb(void)
113{
114 PgStatShared_Checkpointer *stats_shmem = &pgStatLocal.shmem->checkpointer;
115 PgStat_CheckpointerStats *reset_offset = &stats_shmem->reset_offset;
116 PgStat_CheckpointerStats reset;
117
118 pgstat_copy_changecounted_stats(&pgStatLocal.snapshot.checkpointer,
119 &stats_shmem->stats,
120 sizeof(stats_shmem->stats),
121 &stats_shmem->changecount);
122
123 LWLockAcquire(&stats_shmem->lock, LW_SHARED);
124 memcpy(&reset, reset_offset, sizeof(stats_shmem->stats));
125 LWLockRelease(&stats_shmem->lock);
126
127 /* compensate by reset offsets */
128#define CHECKPOINTER_COMP(fld) pgStatLocal.snapshot.checkpointer.fld -= reset.fld;
129 CHECKPOINTER_COMP(num_timed);
130 CHECKPOINTER_COMP(num_requested);
131 CHECKPOINTER_COMP(num_performed);
132 CHECKPOINTER_COMP(restartpoints_timed);
133 CHECKPOINTER_COMP(restartpoints_requested);
134 CHECKPOINTER_COMP(restartpoints_performed);
135 CHECKPOINTER_COMP(write_time);
136 CHECKPOINTER_COMP(sync_time);
137 CHECKPOINTER_COMP(buffers_written);
138 CHECKPOINTER_COMP(slru_written);
139#undef CHECKPOINTER_COMP
140}
#define MemSet(start, val, len)
Definition: c.h:1019
int64 TimestampTz
Definition: timestamp.h:39
Assert(PointerIsAligned(start, uint64))
bool LWLockAcquire(LWLock *lock, LWLockMode mode)
Definition: lwlock.c:1174
void LWLockRelease(LWLock *lock)
Definition: lwlock.c:1894
void LWLockInitialize(LWLock *lock, int tranche_id)
Definition: lwlock.c:698
@ LW_SHARED
Definition: lwlock.h:113
@ LW_EXCLUSIVE
Definition: lwlock.h:112
static bool pg_memory_is_all_zeros(const void *ptr, size_t len)
Definition: memutils.h:219
void pgstat_snapshot_fixed(PgStat_Kind kind)
Definition: pgstat.c:1058
PgStat_LocalState pgStatLocal
Definition: pgstat.c:212
void pgstat_checkpointer_snapshot_cb(void)
void pgstat_checkpointer_init_shmem_cb(void *stats)
#define CHECKPOINTER_COMP(fld)
void pgstat_report_checkpointer(void)
void pgstat_checkpointer_reset_all_cb(TimestampTz ts)
PgStat_CheckpointerStats * pgstat_fetch_stat_checkpointer(void)
PgStat_CheckpointerStats PendingCheckpointerStats
#define CHECKPOINTER_ACC(fld)
static void pgstat_end_changecount_write(uint32 *cc)
#define pgstat_assert_is_up()
static void pgstat_begin_changecount_write(uint32 *cc)
static void pgstat_copy_changecounted_stats(void *dst, void *src, size_t len, uint32 *cc)
void pgstat_flush_io(bool nowait)
Definition: pgstat_io.c:175
#define PGSTAT_KIND_CHECKPOINTER
Definition: pgstat_kind.h:37
void reset(void)
Definition: sql-declare.c:600
uint32 changecount
PgStat_CheckpointerStats reset_offset
PgStat_CheckpointerStats stats
LWLock lock
Definition: pgstat.h:255
TimestampTz stat_reset_timestamp
Definition: pgstat.h:266
PgStat_Snapshot snapshot
PgStat_ShmemControl * shmem
bool is_shutdown
PgStatShared_Checkpointer checkpointer
PgStat_CheckpointerStats checkpointer

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