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tatsuo-ishiitatsuo-ishii
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Add NOWAIT option to LOCK command
1 parent 60a068b commit 0b86ade

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9 files changed

+56
-15
lines changed

9 files changed

+56
-15
lines changed

‎doc/src/sgml/ref/lock.sgml

Lines changed: 6 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
11
<!--
2-
$PostgreSQL: pgsql/doc/src/sgml/ref/lock.sgml,v 1.40 2003/12/14 00:05:29 neilc Exp $
2+
$PostgreSQL: pgsql/doc/src/sgml/ref/lock.sgml,v 1.41 2004/03/11 01:47:35 ishii Exp $
33
PostgreSQL documentation
44
-->
55

@@ -20,7 +20,7 @@ PostgreSQL documentation
2020

2121
<refsynopsisdiv>
2222
<synopsis>
23-
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ IN <replaceable class="PARAMETER">lockmode</replaceable> MODE ]
23+
LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ IN <replaceable class="PARAMETER">lockmode</replaceable> MODE ] [ NOWAIT ]
2424

2525
where <replaceable class="PARAMETER">lockmode</replaceable> is one of:
2626

@@ -34,8 +34,10 @@ where <replaceable class="PARAMETER">lockmode</replaceable> is one of:
3434

3535
<para>
3636
<command>LOCK TABLE</command> obtains a table-level lock, waiting if
37-
necessary for any conflicting locks to be released. Once obtained,
38-
the lock is held for the remainder of the current transaction.
37+
necessary for any conflicting locks to be released.
38+
If <literal>NOWAIT</literal> is given, <command>LOCK TABLE</command>
39+
does not wait for acquiring lock, and throws an error instead.
40+
Once obtained, the lock is held for the remainder of the current transaction.
3941
(There is no <command>UNLOCK TABLE</command> command; locks are always
4042
released at transaction end.)
4143
</para>

‎src/backend/access/heap/heapam.c

Lines changed: 28 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.162 2004/01/16 20:51:30 tgl Exp $
11+
* $PostgreSQL: pgsql/src/backend/access/heap/heapam.c,v 1.163 2004/03/11 01:47:35 ishii Exp $
1212
*
1313
*
1414
* INTERFACE ROUTINES
@@ -464,6 +464,33 @@ relation_open(Oid relationId, LOCKMODE lockmode)
464464
return r;
465465
}
466466

467+
Relation
468+
conditional_relation_open(Oid relationId, LOCKMODE lockmode, bool nowait)
469+
{
470+
Relation r;
471+
472+
Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
473+
474+
/* The relcache does all the real work... */
475+
r = RelationIdGetRelation(relationId);
476+
477+
if (!RelationIsValid(r))
478+
elog(ERROR, "could not open relation with OID %u", relationId);
479+
480+
if (lockmode != NoLock)
481+
{
482+
if (nowait)
483+
{
484+
if (!ConditionalLockRelation(r, lockmode))
485+
elog(ERROR, "could not aquire relation lock");
486+
}
487+
else
488+
LockRelation(r, lockmode);
489+
}
490+
491+
return r;
492+
}
493+
467494
/* ----------------
468495
* relation_openrv - open any relation specified by a RangeVar
469496
*

‎src/backend/commands/lockcmds.c

Lines changed: 2 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/commands/lockcmds.c,v 1.8 2003/11/29 19:51:47 pgsql Exp $
11+
* $PostgreSQL: pgsql/src/backend/commands/lockcmds.c,v 1.9 2004/03/11 01:47:35 ishii Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -59,7 +59,7 @@ LockTableCommand(LockStmt *lockstmt)
5959
aclcheck_error(aclresult, ACL_KIND_CLASS,
6060
get_rel_name(reloid));
6161

62-
rel = relation_open(reloid, lockstmt->mode);
62+
rel = conditional_relation_open(reloid, lockstmt->mode, lockstmt->nowait);
6363

6464
/* Currently, we only allow plain tables to be locked */
6565
if (rel->rd_rel->relkind != RELKIND_RELATION)

‎src/backend/nodes/copyfuncs.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -15,7 +15,7 @@
1515
* Portions Copyright (c) 1994, Regents of the University of California
1616
*
1717
* IDENTIFICATION
18-
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.277 2004/01/14 23:01:54 tgl Exp $
18+
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.278 2004/03/11 01:47:35 ishii Exp $
1919
*
2020
*-------------------------------------------------------------------------
2121
*/
@@ -2316,6 +2316,7 @@ _copyLockStmt(LockStmt *from)
23162316

23172317
COPY_NODE_FIELD(relations);
23182318
COPY_SCALAR_FIELD(mode);
2319+
COPY_SCALAR_FIELD(nowait);
23192320

23202321
return newnode;
23212322
}

‎src/backend/nodes/equalfuncs.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -18,7 +18,7 @@
1818
* Portions Copyright (c) 1994, Regents of the University of California
1919
*
2020
* IDENTIFICATION
21-
* $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.215 2004/01/14 23:01:55 tgl Exp $
21+
* $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.216 2004/03/11 01:47:35 ishii Exp $
2222
*
2323
*-------------------------------------------------------------------------
2424
*/
@@ -1252,6 +1252,7 @@ _equalLockStmt(LockStmt *a, LockStmt *b)
12521252
{
12531253
COMPARE_NODE_FIELD(relations);
12541254
COMPARE_SCALAR_FIELD(mode);
1255+
COMPARE_SCALAR_FIELD(nowait);
12551256

12561257
return true;
12571258
}

‎src/backend/parser/gram.y

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -11,7 +11,7 @@
1111
*
1212
*
1313
* IDENTIFICATION
14-
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.447 2004/03/09 05:05:41 momjian Exp $
14+
* $PostgreSQL: pgsql/src/backend/parser/gram.y,v 2.448 2004/03/11 01:47:37 ishii Exp $
1515
*
1616
* HISTORY
1717
* AUTHOR DATE MAJOR EVENT
@@ -169,6 +169,7 @@ static void doNegateFloat(Value *v);
169169
%type <ival> opt_lock lock_type cast_context
170170
%type <boolean> opt_force opt_or_replace transaction_access_mode
171171
opt_grant_grant_option opt_revoke_grant_option
172+
opt_nowait
172173

173174
%type <boolean> like_including_defaults
174175

@@ -375,7 +376,7 @@ static void doNegateFloat(Value *v);
375376
MATCH MAXVALUE MINUTE_P MINVALUE MODE MONTH_P MOVE
376377

377378
NAMES NATIONAL NATURAL NCHAR NEW NEXT NO NOCREATEDB
378-
NOCREATEUSER NONE NOT NOTHING NOTIFY NOTNULL NULL_P
379+
NOCREATEUSER NONE NOT NOTHING NOTIFY NOTNULL NOWAIT NULL_P
379380
NULLIF NUMERIC
380381

381382
OBJECT_P OF OFF OFFSET OIDS OLD ON ONLY OPERATOR OPTION OR
@@ -4347,12 +4348,13 @@ DeleteStmt: DELETE_P FROM relation_expr where_clause
43474348
}
43484349
;
43494350

4350-
LockStmt: LOCK_P opt_table qualified_name_list opt_lock
4351+
LockStmt: LOCK_P opt_table qualified_name_list opt_lock opt_nowait
43514352
{
43524353
LockStmt *n = makeNode(LockStmt);
43534354

43544355
n->relations = $3;
43554356
n->mode = $4;
4357+
n->nowait = $5;
43564358
$$ = (Node *)n;
43574359
}
43584360
;
@@ -4371,6 +4373,10 @@ lock_type: ACCESS SHARE { $$ = AccessShareLock; }
43714373
| ACCESS EXCLUSIVE { $$ = AccessExclusiveLock; }
43724374
;
43734375

4376+
opt_nowait: NOWAIT { $$ = TRUE; }
4377+
| /*EMPTY*/ { $$ = FALSE; }
4378+
;
4379+
43744380

43754381
/*****************************************************************************
43764382
*
@@ -7683,6 +7689,7 @@ reserved_keyword:
76837689
| LOCALTIMESTAMP
76847690
| NEW
76857691
| NOT
7692+
| NOWAIT
76867693
| NULL_P
76877694
| OFF
76887695
| OFFSET

‎src/backend/parser/keywords.c

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.146 2004/03/09 05:05:41 momjian Exp $
11+
* $PostgreSQL: pgsql/src/backend/parser/keywords.c,v 1.147 2004/03/11 01:47:40 ishii Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -213,6 +213,7 @@ static const ScanKeyword ScanKeywords[] = {
213213
{"nothing", NOTHING},
214214
{"notify", NOTIFY},
215215
{"notnull", NOTNULL},
216+
{"nowait", NOWAIT},
216217
{"null", NULL_P},
217218
{"nullif", NULLIF},
218219
{"numeric", NUMERIC},

‎src/include/access/heapam.h

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.86 2003/11/29 22:40:55 pgsql Exp $
10+
* $PostgreSQL: pgsql/src/include/access/heapam.h,v 1.87 2004/03/11 01:47:41 ishii Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -129,6 +129,7 @@ extern Datum heap_getsysattr(HeapTuple tup, int attnum, bool *isnull);
129129
/* heapam.c */
130130

131131
extern Relation relation_open(Oid relationId, LOCKMODE lockmode);
132+
extern Relation conditional_relation_open(Oid relationId, LOCKMODE lockmode, bool nowait);
132133
extern Relation relation_openrv(const RangeVar *relation, LOCKMODE lockmode);
133134
extern Relation relation_openr(const char *sysRelationName, LOCKMODE lockmode);
134135
extern void relation_close(Relation relation, LOCKMODE lockmode);

‎src/include/nodes/parsenodes.h

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -7,7 +7,7 @@
77
* Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
88
* Portions Copyright (c) 1994, Regents of the University of California
99
*
10-
* $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.253 2004/01/14 23:01:55 tgl Exp $
10+
* $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.254 2004/03/11 01:47:41 ishii Exp $
1111
*
1212
*-------------------------------------------------------------------------
1313
*/
@@ -1619,6 +1619,7 @@ typedef struct LockStmt
16191619
NodeTag type;
16201620
List *relations; /* relations to lock */
16211621
int mode; /* lock mode */
1622+
bool nowait; /* no wait mode */
16221623
} LockStmt;
16231624

16241625
/* ----------------------

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