1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
|
/* -------------------------------------------------------------------------
*
* pgstat_backend.c
* Implementation of backend statistics.
*
* This file contains the implementation of backend statistics. It is kept
* separate from pgstat.c to enforce the line between the statistics access /
* storage implementation and the details about individual types of
* statistics.
*
* This statistics kind uses a proc number as object ID for the hash table
* of pgstats. Entries are created each time a process is spawned, and are
* dropped when the process exits. These are not written to the pgstats file
* on disk.
*
* Copyright (c) 2001-2025, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/backend/utils/activity/pgstat_backend.c
* -------------------------------------------------------------------------
*/
#include "postgres.h"
#include "utils/pgstat_internal.h"
/*
* Returns statistics of a backend by proc number.
*/
PgStat_Backend *
pgstat_fetch_stat_backend(ProcNumber procNumber)
{
PgStat_Backend *backend_entry;
backend_entry = (PgStat_Backend *) pgstat_fetch_entry(PGSTAT_KIND_BACKEND,
InvalidOid, procNumber);
return backend_entry;
}
/*
* Flush out locally pending backend IO statistics. Locking is managed
* by the caller.
*/
static void
pgstat_flush_backend_entry_io(PgStat_EntryRef *entry_ref)
{
PgStatShared_Backend *shbackendent;
PgStat_BackendPending *pendingent;
PgStat_BktypeIO *bktype_shstats;
PgStat_PendingIO *pending_io;
shbackendent = (PgStatShared_Backend *) entry_ref->shared_stats;
pendingent = (PgStat_BackendPending *) entry_ref->pending;
bktype_shstats = &shbackendent->stats.io_stats;
pending_io = &pendingent->pending_io;
for (int io_object = 0; io_object < IOOBJECT_NUM_TYPES; io_object++)
{
for (int io_context = 0; io_context < IOCONTEXT_NUM_TYPES; io_context++)
{
for (int io_op = 0; io_op < IOOP_NUM_TYPES; io_op++)
{
instr_time time;
bktype_shstats->counts[io_object][io_context][io_op] +=
pending_io->counts[io_object][io_context][io_op];
bktype_shstats->bytes[io_object][io_context][io_op] +=
pending_io->bytes[io_object][io_context][io_op];
time = pending_io->pending_times[io_object][io_context][io_op];
bktype_shstats->times[io_object][io_context][io_op] +=
INSTR_TIME_GET_MICROSEC(time);
}
}
}
}
/*
* Wrapper routine to flush backend statistics.
*/
static bool
pgstat_flush_backend_entry(PgStat_EntryRef *entry_ref, bool nowait,
bits32 flags)
{
if (!pgstat_tracks_backend_bktype(MyBackendType))
return false;
if (!pgstat_lock_entry(entry_ref, nowait))
return false;
/* Flush requested statistics */
if (flags & PGSTAT_BACKEND_FLUSH_IO)
pgstat_flush_backend_entry_io(entry_ref);
pgstat_unlock_entry(entry_ref);
return true;
}
/*
* Callback to flush out locally pending backend statistics.
*
* If no stats have been recorded, this function returns false.
*/
bool
pgstat_backend_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
{
return pgstat_flush_backend_entry(entry_ref, nowait, PGSTAT_BACKEND_FLUSH_ALL);
}
/*
* Flush out locally pending backend statistics
*
* "flags" parameter controls which statistics to flush.
*/
void
pgstat_flush_backend(bool nowait, bits32 flags)
{
PgStat_EntryRef *entry_ref;
if (!pgstat_tracks_backend_bktype(MyBackendType))
return;
entry_ref = pgstat_get_entry_ref(PGSTAT_KIND_BACKEND, InvalidOid,
MyProcNumber, false, NULL);
(void) pgstat_flush_backend_entry(entry_ref, nowait, flags);
}
/*
* Create backend statistics entry for proc number.
*/
void
pgstat_create_backend(ProcNumber procnum)
{
PgStat_EntryRef *entry_ref;
PgStatShared_Backend *shstatent;
entry_ref = pgstat_prep_pending_entry(PGSTAT_KIND_BACKEND, InvalidOid,
procnum, NULL);
shstatent = (PgStatShared_Backend *) entry_ref->shared_stats;
/*
* NB: need to accept that there might be stats from an older backend,
* e.g. if we previously used this proc number.
*/
memset(&shstatent->stats, 0, sizeof(shstatent->stats));
}
/*
* Find or create a local PgStat_BackendPending entry for proc number.
*/
PgStat_BackendPending *
pgstat_prep_backend_pending(ProcNumber procnum)
{
PgStat_EntryRef *entry_ref;
entry_ref = pgstat_prep_pending_entry(PGSTAT_KIND_BACKEND, InvalidOid,
procnum, NULL);
return entry_ref->pending;
}
/*
* Backend statistics are not collected for all BackendTypes.
*
* The following BackendTypes do not participate in the backend stats
* subsystem:
* - The same and for the same reasons as in pgstat_tracks_io_bktype().
* - B_BG_WRITER, B_CHECKPOINTER, B_STARTUP and B_AUTOVAC_LAUNCHER because their
* I/O stats are already visible in pg_stat_io and there is only one of those.
*
* Function returns true if BackendType participates in the backend stats
* subsystem and false if it does not.
*
* When adding a new BackendType, also consider adding relevant restrictions to
* pgstat_tracks_io_object() and pgstat_tracks_io_op().
*/
bool
pgstat_tracks_backend_bktype(BackendType bktype)
{
/*
* List every type so that new backend types trigger a warning about
* needing to adjust this switch.
*/
switch (bktype)
{
case B_INVALID:
case B_AUTOVAC_LAUNCHER:
case B_DEAD_END_BACKEND:
case B_ARCHIVER:
case B_LOGGER:
case B_WAL_RECEIVER:
case B_WAL_WRITER:
case B_WAL_SUMMARIZER:
case B_BG_WRITER:
case B_CHECKPOINTER:
case B_STARTUP:
return false;
case B_AUTOVAC_WORKER:
case B_BACKEND:
case B_BG_WORKER:
case B_STANDALONE_BACKEND:
case B_SLOTSYNC_WORKER:
case B_WAL_SENDER:
return true;
}
return false;
}
void
pgstat_backend_reset_timestamp_cb(PgStatShared_Common *header, TimestampTz ts)
{
((PgStatShared_Backend *) header)->stats.stat_reset_timestamp = ts;
}
|
