Re: [PATCHES] NO WAIT ... - Mailing list pgsql-hackers

> > This is missing the necessary adjustments in backend/nodes/ (copy and
> > equal funcs).  Also the NOWAIT keyword must be added to the list of
> > nonreserved keywords near the bottom of gram.y.
> 
> Thanks for the review. I'll work on this.

Here is the revised patch.
--
Tatsuo Ishii
===================================================================
RCS file: /cvsroot/pgsql-server/doc/src/sgml/ref/lock.sgml,v
retrieving revision 1.40
diff -c -r1.40 lock.sgml
*** doc/src/sgml/ref/lock.sgml    14 Dec 2003 00:05:29 -0000    1.40
--- doc/src/sgml/ref/lock.sgml    10 Mar 2004 01:35:18 -0000
***************
*** 20,26 ****   <refsynopsisdiv> <synopsis>
! LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ IN <replaceable
class="PARAMETER">lockmode</replaceable>MODE ]  where <replaceable class="PARAMETER">lockmode</replaceable> is one of:

--- 20,26 ----   <refsynopsisdiv> <synopsis>
! LOCK [ TABLE ] <replaceable class="PARAMETER">name</replaceable> [, ...] [ IN <replaceable
class="PARAMETER">lockmode</replaceable>MODE ] [ NOWAIT ]  where <replaceable class="PARAMETER">lockmode</replaceable>
isone of: 
 
***************
*** 34,41 ****    <para>    <command>LOCK TABLE</command> obtains a table-level lock, waiting if
!    necessary for any conflicting locks to be released.  Once obtained,
!    the lock is held for the remainder of the current transaction.    (There is no <command>UNLOCK TABLE</command>
command;locks are always    released at transaction end.)   </para>
 
--- 34,43 ----    <para>    <command>LOCK TABLE</command> obtains a table-level lock, waiting if
!    necessary for any conflicting locks to be released.
!    If <literal>NOWAIT</literal> is given, <command>LOCK TABLE</command>
!    does not wait for acquiring lock, and throws an error instead.
!    Once obtained, the lock is held for the remainder of the current transaction.    (There is no <command>UNLOCK
TABLE</command>command; locks are always    released at transaction end.)   </para>
 
Index: src/backend/access/heap/heapam.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/access/heap/heapam.c,v
retrieving revision 1.162
diff -c -r1.162 heapam.c
*** src/backend/access/heap/heapam.c    16 Jan 2004 20:51:30 -0000    1.162
--- src/backend/access/heap/heapam.c    10 Mar 2004 01:35:21 -0000
***************
*** 464,469 ****
--- 464,496 ----     return r; } 
+ Relation
+ conditional_relation_open(Oid relationId, LOCKMODE lockmode, bool nowait)
+ {
+     Relation    r;
+ 
+     Assert(lockmode >= NoLock && lockmode < MAX_LOCKMODES);
+ 
+     /* The relcache does all the real work... */
+     r = RelationIdGetRelation(relationId);
+ 
+     if (!RelationIsValid(r))
+         elog(ERROR, "could not open relation with OID %u", relationId);
+ 
+     if (lockmode != NoLock)
+     {
+         if (nowait)
+         {
+             if (!ConditionalLockRelation(r, lockmode))
+                 elog(ERROR, "could not aquire relation lock");
+         }
+         else
+             LockRelation(r, lockmode);
+     }
+ 
+     return r;
+ }
+  /* ----------------  *        relation_openrv - open any relation specified by a RangeVar  *
Index: src/backend/commands/lockcmds.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/commands/lockcmds.c,v
retrieving revision 1.8
diff -c -r1.8 lockcmds.c
*** src/backend/commands/lockcmds.c    29 Nov 2003 19:51:47 -0000    1.8
--- src/backend/commands/lockcmds.c    10 Mar 2004 01:35:21 -0000
***************
*** 59,65 ****             aclcheck_error(aclresult, ACL_KIND_CLASS,                            get_rel_name(reloid));

!         rel = relation_open(reloid, lockstmt->mode);          /* Currently, we only allow plain tables to be locked
*/        if (rel->rd_rel->relkind != RELKIND_RELATION)
 
--- 59,65 ----             aclcheck_error(aclresult, ACL_KIND_CLASS,                            get_rel_name(reloid));

!         rel = conditional_relation_open(reloid, lockstmt->mode, lockstmt->nowait);          /* Currently, we only
allowplain tables to be locked */         if (rel->rd_rel->relkind != RELKIND_RELATION)
 
Index: src/backend/nodes/copyfuncs.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/nodes/copyfuncs.c,v
retrieving revision 1.277
diff -c -r1.277 copyfuncs.c
*** src/backend/nodes/copyfuncs.c    14 Jan 2004 23:01:54 -0000    1.277
--- src/backend/nodes/copyfuncs.c    10 Mar 2004 01:35:25 -0000
***************
*** 2316,2321 ****
--- 2316,2322 ----      COPY_NODE_FIELD(relations);     COPY_SCALAR_FIELD(mode);
+     COPY_SCALAR_FIELD(nowait);      return newnode; }
Index: src/backend/nodes/equalfuncs.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/nodes/equalfuncs.c,v
retrieving revision 1.215
diff -c -r1.215 equalfuncs.c
*** src/backend/nodes/equalfuncs.c    14 Jan 2004 23:01:55 -0000    1.215
--- src/backend/nodes/equalfuncs.c    10 Mar 2004 01:35:28 -0000
***************
*** 1252,1257 ****
--- 1252,1258 ---- {     COMPARE_NODE_FIELD(relations);     COMPARE_SCALAR_FIELD(mode);
+     COMPARE_SCALAR_FIELD(nowait);      return true; }
Index: src/backend/parser/gram.y
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/parser/gram.y,v
retrieving revision 2.447
diff -c -r2.447 gram.y
*** src/backend/parser/gram.y    9 Mar 2004 05:05:41 -0000    2.447
--- src/backend/parser/gram.y    10 Mar 2004 01:35:42 -0000
***************
*** 169,174 ****
--- 169,175 ---- %type <ival>    opt_lock lock_type cast_context %type <boolean>    opt_force opt_or_replace
transaction_access_mode                opt_grant_grant_option opt_revoke_grant_option
 
+                 opt_nowait  %type <boolean>    like_including_defaults 
***************
*** 375,381 ****     MATCH MAXVALUE MINUTE_P MINVALUE MODE MONTH_P MOVE      NAMES NATIONAL NATURAL NCHAR NEW NEXT NO
NOCREATEDB
!     NOCREATEUSER NONE NOT NOTHING NOTIFY NOTNULL NULL_P     NULLIF NUMERIC      OBJECT_P OF OFF OFFSET OIDS OLD ON
ONLYOPERATOR OPTION OR
 
--- 376,382 ----     MATCH MAXVALUE MINUTE_P MINVALUE MODE MONTH_P MOVE      NAMES NATIONAL NATURAL NCHAR NEW NEXT NO
NOCREATEDB
!     NOCREATEUSER NONE NOT NOTHING NOTIFY NOTNULL NOWAIT NULL_P     NULLIF NUMERIC      OBJECT_P OF OFF OFFSET OIDS
OLDON ONLY OPERATOR OPTION OR
 
***************
*** 4347,4358 ****                 }         ; 
! LockStmt:    LOCK_P opt_table qualified_name_list opt_lock                 {                     LockStmt *n =
makeNode(LockStmt);                     n->relations = $3;                     n->mode = $4;                     $$ =
(Node*)n;                 }         ;
 
--- 4348,4360 ----                 }         ; 
! LockStmt:    LOCK_P opt_table qualified_name_list opt_lock opt_nowait                 {                     LockStmt
*n= makeNode(LockStmt);                      n->relations = $3;                     n->mode = $4;
 
+                     n->nowait = $5;                     $$ = (Node *)n;                 }         ;
***************
*** 4371,4376 ****
--- 4373,4382 ----             | ACCESS EXCLUSIVE                { $$ = AccessExclusiveLock; }         ; 
+ opt_nowait:    NOWAIT             { $$ = TRUE; }
+             | /*EMPTY*/                        { $$ = FALSE; }
+         ;
+   /*****************************************************************************  *
***************
*** 7683,7688 ****
--- 7689,7695 ----             | LOCALTIMESTAMP             | NEW             | NOT
+             | NOWAIT             | NULL_P             | OFF             | OFFSET
Index: src/backend/parser/keywords.c
===================================================================
RCS file: /cvsroot/pgsql-server/src/backend/parser/keywords.c,v
retrieving revision 1.146
diff -c -r1.146 keywords.c
*** src/backend/parser/keywords.c    9 Mar 2004 05:05:41 -0000    1.146
--- src/backend/parser/keywords.c    10 Mar 2004 01:35:42 -0000
***************
*** 213,218 ****
--- 213,219 ----     {"nothing", NOTHING},     {"notify", NOTIFY},     {"notnull", NOTNULL},
+     {"nowait", NOWAIT},     {"null", NULL_P},     {"nullif", NULLIF},     {"numeric", NUMERIC},
Index: src/include/access/heapam.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/access/heapam.h,v
retrieving revision 1.86
diff -c -r1.86 heapam.h
*** src/include/access/heapam.h    29 Nov 2003 22:40:55 -0000    1.86
--- src/include/access/heapam.h    10 Mar 2004 01:35:46 -0000
***************
*** 129,134 ****
--- 129,135 ---- /* heapam.c */  extern Relation relation_open(Oid relationId, LOCKMODE lockmode);
+ extern Relation conditional_relation_open(Oid relationId, LOCKMODE lockmode, bool nowait); extern Relation
relation_openrv(constRangeVar *relation, LOCKMODE lockmode); extern Relation relation_openr(const char
*sysRelationName,LOCKMODE lockmode); extern void relation_close(Relation relation, LOCKMODE lockmode);
 
Index: src/include/nodes/parsenodes.h
===================================================================
RCS file: /cvsroot/pgsql-server/src/include/nodes/parsenodes.h,v
retrieving revision 1.253
diff -c -r1.253 parsenodes.h
*** src/include/nodes/parsenodes.h    14 Jan 2004 23:01:55 -0000    1.253
--- src/include/nodes/parsenodes.h    10 Mar 2004 01:35:49 -0000
***************
*** 1619,1624 ****
--- 1619,1625 ----     NodeTag        type;     List       *relations;        /* relations to lock */     int
mode;            /* lock mode */
 
+     bool        nowait;        /* no wait mode */ } LockStmt;  /* ----------------------