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
|
/*-------------------------------------------------------------------------
*
* mcxtfuncs.c
* Functions to show backend memory context.
*
* Portions Copyright (c) 1996-2021, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* src/backend/utils/adt/mcxtfuncs.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "mb/pg_wchar.h"
#include "storage/proc.h"
#include "storage/procarray.h"
#include "utils/builtins.h"
/* ----------
* The max bytes for showing identifiers of MemoryContext.
* ----------
*/
#define MEMORY_CONTEXT_IDENT_DISPLAY_SIZE 1024
/*
* PutMemoryContextsStatsTupleStore
* One recursion level for pg_get_backend_memory_contexts.
*/
static void
PutMemoryContextsStatsTupleStore(Tuplestorestate *tupstore,
TupleDesc tupdesc, MemoryContext context,
const char *parent, int level)
{
#define PG_GET_BACKEND_MEMORY_CONTEXTS_COLS 9
Datum values[PG_GET_BACKEND_MEMORY_CONTEXTS_COLS];
bool nulls[PG_GET_BACKEND_MEMORY_CONTEXTS_COLS];
MemoryContextCounters stat;
MemoryContext child;
const char *name;
const char *ident;
AssertArg(MemoryContextIsValid(context));
name = context->name;
ident = context->ident;
/*
* To be consistent with logging output, we label dynahash contexts with
* just the hash table name as with MemoryContextStatsPrint().
*/
if (ident && strcmp(name, "dynahash") == 0)
{
name = ident;
ident = NULL;
}
/* Examine the context itself */
memset(&stat, 0, sizeof(stat));
(*context->methods->stats) (context, NULL, (void *) &level, &stat, true);
memset(values, 0, sizeof(values));
memset(nulls, 0, sizeof(nulls));
if (name)
values[0] = CStringGetTextDatum(name);
else
nulls[0] = true;
if (ident)
{
int idlen = strlen(ident);
char clipped_ident[MEMORY_CONTEXT_IDENT_DISPLAY_SIZE];
/*
* Some identifiers such as SQL query string can be very long,
* truncate oversize identifiers.
*/
if (idlen >= MEMORY_CONTEXT_IDENT_DISPLAY_SIZE)
idlen = pg_mbcliplen(ident, idlen, MEMORY_CONTEXT_IDENT_DISPLAY_SIZE - 1);
memcpy(clipped_ident, ident, idlen);
clipped_ident[idlen] = '\0';
values[1] = CStringGetTextDatum(clipped_ident);
}
else
nulls[1] = true;
if (parent)
values[2] = CStringGetTextDatum(parent);
else
nulls[2] = true;
values[3] = Int32GetDatum(level);
values[4] = Int64GetDatum(stat.totalspace);
values[5] = Int64GetDatum(stat.nblocks);
values[6] = Int64GetDatum(stat.freespace);
values[7] = Int64GetDatum(stat.freechunks);
values[8] = Int64GetDatum(stat.totalspace - stat.freespace);
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
for (child = context->firstchild; child != NULL; child = child->nextchild)
{
PutMemoryContextsStatsTupleStore(tupstore, tupdesc,
child, name, level + 1);
}
}
/*
* pg_get_backend_memory_contexts
* SQL SRF showing backend memory context.
*/
Datum
pg_get_backend_memory_contexts(PG_FUNCTION_ARGS)
{
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not allowed in this context")));
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
PutMemoryContextsStatsTupleStore(tupstore, tupdesc,
TopMemoryContext, NULL, 0);
/* clean up and return the tuplestore */
tuplestore_donestoring(tupstore);
return (Datum) 0;
}
/*
* pg_log_backend_memory_contexts
* Signal a backend process to log its memory contexts.
*
* Only superusers are allowed to signal to log the memory contexts
* because allowing any users to issue this request at an unbounded
* rate would cause lots of log messages and which can lead to
* denial of service.
*
* On receipt of this signal, a backend sets the flag in the signal
* handler, which causes the next CHECK_FOR_INTERRUPTS() to log the
* memory contexts.
*/
Datum
pg_log_backend_memory_contexts(PG_FUNCTION_ARGS)
{
int pid = PG_GETARG_INT32(0);
PGPROC *proc;
/* Only allow superusers to log memory contexts. */
if (!superuser())
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
errmsg("must be a superuser to log memory contexts")));
proc = BackendPidGetProc(pid);
/*
* BackendPidGetProc returns NULL if the pid isn't valid; but by the time
* we reach kill(), a process for which we get a valid proc here might
* have terminated on its own. There's no way to acquire a lock on an
* arbitrary process to prevent that. But since this mechanism is usually
* used to debug a backend running and consuming lots of memory, that it
* might end on its own first and its memory contexts are not logged is
* not a problem.
*/
if (proc == NULL)
{
/*
* This is just a warning so a loop-through-resultset will not abort
* if one backend terminated on its own during the run.
*/
ereport(WARNING,
(errmsg("PID %d is not a PostgreSQL server process", pid)));
PG_RETURN_BOOL(false);
}
if (SendProcSignal(pid, PROCSIG_LOG_MEMORY_CONTEXT, proc->backendId) < 0)
{
/* Again, just a warning to allow loops */
ereport(WARNING,
(errmsg("could not send signal to process %d: %m", pid)));
PG_RETURN_BOOL(false);
}
PG_RETURN_BOOL(true);
}
|
