Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitf577919

Browse files
committed
Add pinning_backends column to the pg_buffercache extension.
The new column shows how many backends have a buffer pinned. That canbe useful during development or to diagnose production issuese.g. caused by vacuum waiting for cleanup locks.To handle upgrades transparently - the extension might be used inviews - deal with callers expecting the old number of columns.Reviewed by Fujii Masao and Rajeev rastogi.
1 parentce48605 commitf577919

File tree

6 files changed

+58
-6
lines changed

6 files changed

+58
-6
lines changed

‎contrib/pg_buffercache/Makefile

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -4,7 +4,7 @@ MODULE_big = pg_buffercache
44
OBJS = pg_buffercache_pages.o$(WIN32RES)
55

66
EXTENSION = pg_buffercache
7-
DATA = pg_buffercache--1.0.sql pg_buffercache--unpackaged--1.0.sql
7+
DATA = pg_buffercache--1.1.sql pg_buffercache--1.0--1.1.sql pg_buffercache--unpackaged--1.0.sql
88
PGFILEDESC = "pg_buffercache - monitoring of shared buffer cache in real-time"
99

1010
ifdefUSE_PGXS
Lines changed: 11 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,11 @@
1+
/* contrib/pg_buffercache/pg_buffercache--1.0--1.1.sql*/
2+
3+
-- complain if script is sourced in psql, rather than via ALTER EXTENSION
4+
\echo Use"ALTER EXTENSION pg_buffercache UPDATE TO '1.1'" to load this file. \quit
5+
6+
-- Upgrade view to 1.1. format
7+
CREATE OR REPLACEVIEWpg_buffercacheAS
8+
SELECT P.*FROM pg_buffercache_pages()AS P
9+
(bufferidinteger, relfilenodeoid, reltablespaceoid, reldatabaseoid,
10+
relforknumber int2, relblocknumber int8, isdirty bool, usagecount int2,
11+
pinning_backends int4);

‎contrib/pg_buffercache/pg_buffercache--1.0.sqlrenamed to‎contrib/pg_buffercache/pg_buffercache--1.1.sql

Lines changed: 3 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1,4 +1,4 @@
1-
/* contrib/pg_buffercache/pg_buffercache--1.0.sql*/
1+
/* contrib/pg_buffercache/pg_buffercache--1.1.sql*/
22

33
-- complain if script is sourced in psql, rather than via CREATE EXTENSION
44
\echo Use"CREATE EXTENSION pg_buffercache" to load this file. \quit
@@ -13,7 +13,8 @@ LANGUAGE C;
1313
CREATEVIEWpg_buffercacheAS
1414
SELECT P.*FROM pg_buffercache_pages()AS P
1515
(bufferidinteger, relfilenodeoid, reltablespaceoid, reldatabaseoid,
16-
relforknumber int2, relblocknumber int8, isdirty bool, usagecount int2);
16+
relforknumber int2, relblocknumber int8, isdirty bool, usagecount int2,
17+
pinning_backends int4);
1718

1819
-- Don't want these to be available to public.
1920
REVOKE ALLON FUNCTION pg_buffercache_pages()FROM PUBLIC;
Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
# pg_buffercache extension
22
comment = 'examine the shared buffer cache'
3-
default_version = '1.0'
3+
default_version = '1.1'
44
module_pathname = '$libdir/pg_buffercache'
55
relocatable = true

‎contrib/pg_buffercache/pg_buffercache_pages.c

Lines changed: 35 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,8 @@
1515
#include"storage/bufmgr.h"
1616

1717

18-
#defineNUM_BUFFERCACHE_PAGES_ELEM8
18+
#defineNUM_BUFFERCACHE_PAGES_MIN_ELEM8
19+
#defineNUM_BUFFERCACHE_PAGES_ELEM9
1920

2021
PG_MODULE_MAGIC;
2122

@@ -33,6 +34,12 @@ typedef struct
3334
boolisvalid;
3435
boolisdirty;
3536
uint16usagecount;
37+
/*
38+
* An int32 is sufficiently large, as MAX_BACKENDS prevents a buffer from
39+
* being pinned by too many backends and each backend will only pin once
40+
* because of bufmgr.c's PrivateRefCount array.
41+
*/
42+
int32pinning_backends;
3643
}BufferCachePagesRec;
3744

3845

@@ -60,6 +67,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
6067
MemoryContextoldcontext;
6168
BufferCachePagesContext*fctx;/* User function context. */
6269
TupleDesctupledesc;
70+
TupleDescexpected_tupledesc;
6371
HeapTupletuple;
6472

6573
if (SRF_IS_FIRSTCALL())
@@ -75,8 +83,23 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
7583
/* Create a user function context for cross-call persistence */
7684
fctx= (BufferCachePagesContext*)palloc(sizeof(BufferCachePagesContext));
7785

86+
/*
87+
* To smoothly support upgrades from version 1.0 of this extension
88+
* transparently handle the (non-)existance of the pinning_backends
89+
* column. We unfortunately have to get the result type for that... -
90+
* we can't use the result type determined by the function definition
91+
* without potentially crashing when somebody uses the old (or even
92+
* wrong) function definition though.
93+
*/
94+
if (get_call_result_type(fcinfo,NULL,&expected_tupledesc)!=TYPEFUNC_COMPOSITE)
95+
elog(ERROR,"return type must be a row type");
96+
97+
if (expected_tupledesc->natts<NUM_BUFFERCACHE_PAGES_MIN_ELEM||
98+
expected_tupledesc->natts>NUM_BUFFERCACHE_PAGES_ELEM)
99+
elog(ERROR,"incorrect number of output arguments");
100+
78101
/* Construct a tuple descriptor for the result rows. */
79-
tupledesc=CreateTemplateTupleDesc(NUM_BUFFERCACHE_PAGES_ELEM, false);
102+
tupledesc=CreateTemplateTupleDesc(expected_tupledesc->natts, false);
80103
TupleDescInitEntry(tupledesc, (AttrNumber)1,"bufferid",
81104
INT4OID,-1,0);
82105
TupleDescInitEntry(tupledesc, (AttrNumber)2,"relfilenode",
@@ -94,6 +117,10 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
94117
TupleDescInitEntry(tupledesc, (AttrNumber)8,"usage_count",
95118
INT2OID,-1,0);
96119

120+
if (expected_tupledesc->natts==NUM_BUFFERCACHE_PAGES_ELEM)
121+
TupleDescInitEntry(tupledesc, (AttrNumber)9,"pinning_backends",
122+
INT4OID,-1,0);
123+
97124
fctx->tupdesc=BlessTupleDesc(tupledesc);
98125

99126
/* Allocate NBuffers worth of BufferCachePagesRec records. */
@@ -131,6 +158,7 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
131158
fctx->record[i].forknum=bufHdr->tag.forkNum;
132159
fctx->record[i].blocknum=bufHdr->tag.blockNum;
133160
fctx->record[i].usagecount=bufHdr->usage_count;
161+
fctx->record[i].pinning_backends=bufHdr->refcount;
134162

135163
if (bufHdr->flags&BM_DIRTY)
136164
fctx->record[i].isdirty= true;
@@ -185,6 +213,8 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
185213
nulls[5]= true;
186214
nulls[6]= true;
187215
nulls[7]= true;
216+
/* unused for v1.0 callers, but the array is always long enough */
217+
nulls[8]= true;
188218
}
189219
else
190220
{
@@ -202,6 +232,9 @@ pg_buffercache_pages(PG_FUNCTION_ARGS)
202232
nulls[6]= false;
203233
values[7]=Int16GetDatum(fctx->record[i].usagecount);
204234
nulls[7]= false;
235+
/* unused for v1.0 callers, but the array is always long enough */
236+
values[8]=Int32GetDatum(fctx->record[i].pinning_backends);
237+
nulls[8]= false;
205238
}
206239

207240
/* Build and return the tuple. */

‎doc/src/sgml/pgbuffercache.sgml

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -106,6 +106,13 @@
106106
<entry>Clock-sweep access count</entry>
107107
</row>
108108

109+
<row>
110+
<entry><structfield>pinning_backends</structfield></entry>
111+
<entry><type>integer</type></entry>
112+
<entry></entry>
113+
<entry>Number of backends pinning this buffer</entry>
114+
</row>
115+
109116
</tbody>
110117
</tgroup>
111118
</table>

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp