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Commit4fe42df

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Add SHARE UPDATE EXCLUSIVE lock mode, coming soon to a VACUUM near you.
Name chosen per pghackers discussion around 6/22/01.
1 parent8902f49 commit4fe42df

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8 files changed

+143
-80
lines changed

8 files changed

+143
-80
lines changed

‎doc/src/sgml/mvcc.sgml‎

Lines changed: 28 additions & 6 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.15 2001/05/17 21:50:16 petere Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/mvcc.sgml,v 2.16 2001/07/09 22:18:33 tgl Exp $
33
-->
44

55
<chapter id="mvcc">
@@ -441,6 +441,25 @@ ERROR: Can't serialize access due to concurrent update
441441
</listitem>
442442
</varlistentry>
443443

444+
<varlistentry>
445+
<term>
446+
ShareUpdateExclusiveLock
447+
</term>
448+
<listitem>
449+
<para>
450+
Acquired by <command>VACUUM</command> (without <option>FULL</option>)
451+
and <command>LOCK TABLE</command> table
452+
for <option>IN SHARE UPDATE EXCLUSIVE MODE</option>
453+
statements.
454+
</para>
455+
456+
<para>
457+
Conflicts with ShareUpdateExclusiveLock, ShareLock,
458+
ShareRowExclusiveLock, ExclusiveLock and AccessExclusiveLock modes.
459+
</para>
460+
</listitem>
461+
</varlistentry>
462+
444463
<varlistentry>
445464
<term>
446465
ShareLock
@@ -454,7 +473,8 @@ ERROR: Can't serialize access due to concurrent update
454473
</para>
455474

456475
<para>
457-
Conflicts with RowExclusiveLock, ShareRowExclusiveLock,
476+
Conflicts with RowExclusiveLock, ShareUpdateExclusiveLock,
477+
ShareRowExclusiveLock,
458478
ExclusiveLock and AccessExclusiveLock modes.
459479
</para>
460480
</listitem>
@@ -471,7 +491,8 @@ ERROR: Can't serialize access due to concurrent update
471491
</para>
472492

473493
<para>
474-
Conflicts with RowExclusiveLock, ShareLock, ShareRowExclusiveLock,
494+
Conflicts with RowExclusiveLock, ShareUpdateExclusiveLock,
495+
ShareLock, ShareRowExclusiveLock,
475496
ExclusiveLock and AccessExclusiveLock modes.
476497
</para>
477498
</listitem>
@@ -488,7 +509,8 @@ ERROR: Can't serialize access due to concurrent update
488509
</para>
489510

490511
<para>
491-
Conflicts with RowShareLock, RowExclusiveLock, ShareLock,
512+
Conflicts with RowShareLock, RowExclusiveLock,
513+
ShareUpdateExclusiveLock, ShareLock,
492514
ShareRowExclusiveLock, ExclusiveLock and AccessExclusiveLock
493515
modes.
494516
</para>
@@ -503,13 +525,13 @@ ERROR: Can't serialize access due to concurrent update
503525
<para>
504526
Acquired by <command>ALTER TABLE</command>,
505527
<command>DROP TABLE</command>,
506-
<command>VACUUM</command> and <command>LOCK TABLE</command>
528+
<command>VACUUM FULL</command> and <command>LOCK TABLE</command>
507529
statements.
508530
</para>
509531

510532
<para>
511533
Conflicts with all modes (AccessShareLock, RowShareLock,
512-
RowExclusiveLock, ShareLock,
534+
RowExclusiveLock,ShareUpdateExclusiveLock,ShareLock,
513535
ShareRowExclusiveLock, ExclusiveLock and AccessExclusiveLock).
514536
</para>
515537
</listitem>

‎doc/src/sgml/ref/lock.sgml‎

Lines changed: 53 additions & 26 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$Header: /cvsroot/pgsql/doc/src/sgml/ref/lock.sgml,v 1.23 2000/12/25 23:15:26 petere Exp $
2+
$Header: /cvsroot/pgsql/doc/src/sgml/ref/lock.sgml,v 1.24 2001/07/09 22:18:33 tgl Exp $
33
Postgres documentation
44
-->
55

@@ -20,20 +20,23 @@ Postgres documentation
2020
</refnamediv>
2121
<refsynopsisdiv>
2222
<refsynopsisdivinfo>
23-
<date>1999-07-20</date>
23+
<date>2001-07-09</date>
2424
</refsynopsisdivinfo>
2525
<synopsis>
2626
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable>
27-
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN [ ROW | ACCESS ] { SHARE | EXCLUSIVE } MODE
28-
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EXCLUSIVE MODE
27+
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN <replaceable class="PARAMETER">lockmode</replaceable> MODE
28+
29+
where <replaceable class="PARAMETER">lockmode</replaceable> is one of:
30+
31+
ACCESS SHARE | ROW SHARE | ROW EXCLUSIVE | SHARE UPDATE EXCLUSIVE |
32+
SHARE | SHARE ROW EXCLUSIVE | EXCLUSIVE | ACCESS EXCLUSIVE
2933
</synopsis>
3034

3135
<refsect2 id="R2-SQL-LOCK-1">
3236
<refsect2info>
3337
<date>1999-06-09</date>
3438
</refsect2info>
3539

36-
3740
<title>
3841
Inputs
3942
</title>
@@ -62,7 +65,7 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
6265
This is the least restrictive lock mode. It conflicts only with
6366
ACCESS EXCLUSIVE mode. It is used to protect a table from being
6467
modified by concurrent <command>ALTER TABLE</command>,
65-
<command>DROP TABLE</command> and <command>VACUUM</command>
68+
<command>DROP TABLE</command> and <command>VACUUM FULL</command>
6669
commands.
6770
</para>
6871
</listitem>
@@ -102,6 +105,25 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
102105
</listitem>
103106
</varlistentry>
104107

108+
<varlistentry>
109+
<term>SHARE UPDATE EXCLUSIVE MODE</term>
110+
<listitem>
111+
<note>
112+
<para>
113+
Automatically acquired by <command>VACUUM</command> (without
114+
<option>FULL</option>).
115+
</para>
116+
</note>
117+
118+
<para>
119+
Conflicts with SHARE UPDATE EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE,
120+
EXCLUSIVE and
121+
ACCESS EXCLUSIVE modes. This mode protects a table against
122+
concurrent schema changes and VACUUMs.
123+
</para>
124+
</listitem>
125+
</varlistentry>
126+
105127
<varlistentry>
106128
<term>SHARE MODE</term>
107129
<listitem>
@@ -113,9 +135,10 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
113135
</note>
114136

115137
<para>
116-
Conflicts with ROW EXCLUSIVE, SHARE ROW EXCLUSIVE, EXCLUSIVE and
138+
Conflicts with ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE,
139+
SHARE ROW EXCLUSIVE, EXCLUSIVE and
117140
ACCESS EXCLUSIVE modes. This mode protects a table against
118-
concurrent updates.
141+
concurrentdataupdates.
119142
</para>
120143
</listitem>
121144
</varlistentry>
@@ -125,14 +148,14 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
125148
<listitem>
126149
<note>
127150
<para>
128-
This is like EXCLUSIVE MODE, but allowsSHAREROW locks
151+
This is like EXCLUSIVE MODE, but allows ROW SHARE locks
129152
by others.
130153
</para>
131154
</note>
132155

133156
<para>
134-
Conflicts with ROW EXCLUSIVE, SHARE, SHARE ROWEXCLUSIVE,
135-
EXCLUSIVE and ACCESS EXCLUSIVE modes.
157+
Conflicts with ROW EXCLUSIVE, SHARE UPDATEEXCLUSIVE, SHARE,
158+
SHARE ROW EXCLUSIVE,EXCLUSIVE and ACCESS EXCLUSIVE modes.
136159
</para>
137160
</listitem>
138161
</varlistentry>
@@ -149,7 +172,8 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
149172
</note>
150173

151174
<para>
152-
Conflicts with ROW SHARE, ROW EXCLUSIVE, SHARE, SHARE ROW EXCLUSIVE,
175+
Conflicts with ROW SHARE, ROW EXCLUSIVE, SHARE UPDATE EXCLUSIVE,
176+
SHARE, SHARE ROW EXCLUSIVE,
153177
EXCLUSIVE and ACCESS EXCLUSIVE modes.
154178
</para>
155179
</listitem>
@@ -161,9 +185,10 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
161185
<note>
162186
<para>
163187
Automatically acquired by <command>ALTER TABLE</command>,
164-
<command>DROP TABLE</command>, <command>VACUUM</command> statements.
165-
This is the most restrictive lock mode which conflicts with all other
166-
lock modes and protects a locked table from any concurrent operations.
188+
<command>DROP TABLE</command>, <command>VACUUM FULL</command>
189+
statements.
190+
This is the most restrictive lock mode which
191+
protects a locked table from any concurrent operations.
167192
</para>
168193
</note>
169194

@@ -174,6 +199,10 @@ LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> IN SHARE ROW EX
174199
lock mode option).
175200
</para>
176201
</note>
202+
203+
<para>
204+
Conflicts with all lock modes.
205+
</para>
177206
</listitem>
178207
</varlistentry>
179208
</variablelist>
@@ -241,7 +270,11 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
241270
<term>EXCLUSIVE</term>
242271
<listitem>
243272
<para>
244-
Exclusive lock that prevents other locks from being granted.
273+
An exclusive lock prevents other locks of the same type from being
274+
granted. (Note: ROW EXCLUSIVE mode does not follow this naming
275+
convention perfectly, since it is shared at the level of the table;
276+
it is exclusive only with respect to specific rows that are being
277+
updated.)
245278
</para>
246279
</listitem>
247280
</varlistentry>
@@ -250,7 +283,8 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
250283
<term>SHARE</term>
251284
<listitem>
252285
<para>
253-
Allows others to share lock. Prevents EXCLUSIVE locks.
286+
A shared lock allows others to also hold the same type of lock,
287+
but prevents the corresponding EXCLUSIVE lock from being granted.
254288
</para>
255289
</listitem>
256290
</varlistentry>
@@ -273,13 +307,6 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
273307
</listitem>
274308
</varlistentry>
275309
</variablelist>
276-
277-
<note>
278-
<para>
279-
If EXCLUSIVE or SHARE are not specified, EXCLUSIVE is assumed.
280-
Locks exist for the duration of the transaction.
281-
</para>
282-
</note>
283310
</para>
284311

285312
<para>
@@ -370,8 +397,8 @@ ERROR <replaceable class="PARAMETER">name</replaceable>: Table does not exist.
370397
</para>
371398

372399
<para>
373-
Except for ACCESS SHARE/EXCLUSIVE lock modes, all other
374-
<productname>Postgres</productname> lock modes and the
400+
Except for ACCESS SHARE, ACCESS EXCLUSIVE, and SHARE UPDATE EXCLUSIVE lock
401+
modes, the<productname>Postgres</productname> lock modes and the
375402
<command>LOCK TABLE</command> syntax are compatible with those
376403
present in <productname>Oracle</productname>.
377404
</para>

‎src/backend/parser/gram.y‎

Lines changed: 11 additions & 11 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.233 2001/06/30 22:03:25 petere Exp $
14+
* $Header: /cvsroot/pgsql/src/backend/parser/gram.y,v 2.234 2001/07/09 22:18:33 tgl Exp $
1515
*
1616
* HISTORY
1717
* AUTHORDATEMAJOR EVENT
@@ -153,7 +153,7 @@ static void doNegateFloat(Value *v);
153153
%type<list>createdb_opt_list,createdb_opt_item
154154

155155
%type<ival>opt_lock,lock_type
156-
%type<boolean>opt_lmode,opt_force
156+
%type<boolean>opt_force
157157

158158
%type<ival>user_createdb_clause,user_createuser_clause
159159
%type<str>user_passwd_clause
@@ -3277,18 +3277,18 @@ LockStmt:LOCK_P opt_table relation_name opt_lock
32773277
}
32783278
;
32793279

3280-
opt_lock:INlock_typeMODE{$$ =$2; }
3280+
opt_lock:INlock_typeMODE{$$ =$2; }
32813281
|/*EMPTY*/{$$ = AccessExclusiveLock; }
32823282
;
32833283

3284-
lock_type:SHAREROWEXCLUSIVE{$$ =ShareRowExclusiveLock; }
3285-
|ROWopt_lmode{$$ =($2?RowShareLock: RowExclusiveLock); }
3286-
|ACCESSopt_lmode{$$ =($2? AccessShareLock: AccessExclusiveLock); }
3287-
|opt_lmode{$$ =($1? ShareLock: ExclusiveLock); }
3288-
;
3289-
3290-
opt_lmode:SHARE{$$ =TRUE; }
3291-
|EXCLUSIVE{$$ =FALSE; }
3284+
lock_type:ACCESSSHARE{$$ =AccessShareLock; }
3285+
|ROWSHARE{$$ = RowShareLock; }
3286+
|ROWEXCLUSIVE{$$ =RowExclusiveLock; }
3287+
|SHAREUPDATEEXCLUSIVE{$$ =ShareUpdateExclusiveLock; }
3288+
|SHARE{$$ = ShareLock; }
3289+
|SHAREROWEXCLUSIVE{$$ = ShareRowExclusiveLock; }
3290+
|EXCLUSIVE{$$ =ExclusiveLock; }
3291+
|ACCESSEXCLUSIVE{$$ =AccessExclusiveLock; }
32923292
;
32933293

32943294

‎src/backend/storage/lmgr/lmgr.c‎

Lines changed: 28 additions & 16 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lmgr.c,v 1.48 2001/06/22 00:04:59 tgl Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/storage/lmgr/lmgr.c,v 1.49 2001/07/09 22:18:33 tgl Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -33,25 +33,35 @@ static LOCKMASK LockConflicts[] = {
3333
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock),
3434

3535
/* RowExclusiveLock */
36-
(1 <<ExclusiveLock) | (1 <<ShareRowExclusiveLock) | (1 <<ShareLock) |
37-
(1 <<AccessExclusiveLock),
36+
(1 <<ShareLock) | (1 <<ShareRowExclusiveLock) |
37+
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock),
38+
39+
/* ShareUpdateExclusiveLock */
40+
(1 <<ShareUpdateExclusiveLock) |
41+
(1 <<ShareLock) | (1 <<ShareRowExclusiveLock) |
42+
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock),
3843

3944
/* ShareLock */
40-
(1 <<ExclusiveLock) | (1 <<ShareRowExclusiveLock) |
41-
(1 <<RowExclusiveLock) | (1 <<AccessExclusiveLock),
45+
(1 <<RowExclusiveLock) | (1 <<ShareUpdateExclusiveLock) |
46+
(1 <<ShareRowExclusiveLock) |
47+
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock),
4248

4349
/* ShareRowExclusiveLock */
44-
(1 <<ExclusiveLock) | (1 <<ShareRowExclusiveLock) |
45-
(1 <<ShareLock) | (1 <<RowExclusiveLock) | (1 <<AccessExclusiveLock),
50+
(1 <<RowExclusiveLock) | (1 <<ShareUpdateExclusiveLock) |
51+
(1 <<ShareLock) | (1 <<ShareRowExclusiveLock) |
52+
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock),
4653

4754
/* ExclusiveLock */
48-
(1 <<ExclusiveLock) | (1 <<ShareRowExclusiveLock) | (1 <<ShareLock) |
49-
(1 <<RowExclusiveLock) | (1 <<RowShareLock) | (1 <<AccessExclusiveLock),
55+
(1 <<RowShareLock) |
56+
(1 <<RowExclusiveLock) | (1 <<ShareUpdateExclusiveLock) |
57+
(1 <<ShareLock) | (1 <<ShareRowExclusiveLock) |
58+
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock),
5059

5160
/* AccessExclusiveLock */
52-
(1 <<ExclusiveLock) | (1 <<ShareRowExclusiveLock) | (1 <<ShareLock) |
53-
(1 <<RowExclusiveLock) | (1 <<RowShareLock) |
54-
(1 <<AccessExclusiveLock) | (1 <<AccessShareLock)
61+
(1 <<AccessShareLock) | (1 <<RowShareLock) |
62+
(1 <<RowExclusiveLock) | (1 <<ShareUpdateExclusiveLock) |
63+
(1 <<ShareLock) | (1 <<ShareRowExclusiveLock) |
64+
(1 <<ExclusiveLock) | (1 <<AccessExclusiveLock)
5565

5666
};
5767

@@ -63,14 +73,16 @@ static intLockPrios[] = {
6373
2,
6474
/* RowExclusiveLock */
6575
3,
66-
/*ShareLock */
76+
/*ShareUpdateExclusiveLock */
6777
4,
68-
/*ShareRowExclusiveLock */
78+
/*ShareLock */
6979
5,
70-
/*ExclusiveLock */
80+
/*ShareRowExclusiveLock */
7181
6,
82+
/* ExclusiveLock */
83+
7,
7284
/* AccessExclusiveLock */
73-
7
85+
8
7486
};
7587

7688
LOCKMETHODLockTableId= (LOCKMETHOD)NULL;

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