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Bruce Momjian wrote:
> 
> Uh, seems the code has drifted too much and now I can't apply this. 
> Would you redo this against current CVS?  Thanks.
> 
> ---------------------------------------------------------------------------
> 
> Hans-Juergen Schoenig wrote:
> > Folks,
> > 
> > We have implemented SELECT FOR UPDATE NOWAIT for PostgreSQL.
> > The patch attached to this email contains all the required code 
> > including ECPG updates and some documentation.
> > It would be nice if this patch would be included in PostgreSQL 8.1
> > 
> >     Best regards,
> > 
> >             Ewald Geschwinde & Hans-Juergen Schoenig
> > 
> > --
> > Cybertec Geschwinde u Schoenig GmbH.
> > Schoengrabern 134, A-2020 Hollabrunn, Austria
> > Tel: +43/660/816 40 77
> > www.cybertec.at, www.postgresql.at
> 
> [ text/x-patch is unsupported, treating like TEXT/PLAIN ]
> 
> > diff -r -c postgresql-8.0.0rc2.orig/doc/src/sgml/ref/select.sgml 
> > postgresql-8.0.0rc2/doc/src/sgml/ref/select.sgml
> > *** postgresql-8.0.0rc2.orig/doc/src/sgml/ref/select.sgml   Sat Nov 27 
> > 22:27:07 2004
> > --- postgresql-8.0.0rc2/doc/src/sgml/ref/select.sgml        Mon Dec 27 
> > 10:57:05 2004
> > ***************
> > *** 30,36 ****
> >       [ ORDER BY <replaceable class="parameter">expression</replaceable> [ 
> > ASC | DESC | USING <replaceable class="parameter">operator</replaceable> ] 
> > [, ...] ]
> >       [ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ]
> >       [ OFFSET <replaceable class="parameter">start</replaceable> ]
> > !     [ FOR UPDATE [ OF <replaceable 
> > class="parameter">table_name</replaceable> [, ...] ] ]
> >   
> >   where <replaceable class="parameter">from_item</replaceable> can be one 
> > of:
> >   
> > --- 30,36 ----
> >       [ ORDER BY <replaceable class="parameter">expression</replaceable> [ 
> > ASC | DESC | USING <replaceable class="parameter">operator</replaceable> ] 
> > [, ...] ]
> >       [ LIMIT { <replaceable class="parameter">count</replaceable> | ALL } ]
> >       [ OFFSET <replaceable class="parameter">start</replaceable> ]
> > !     [ FOR UPDATE [ OF <replaceable 
> > class="parameter">table_name</replaceable> [, ...] ] [NOWAIT] ]
> >   
> >   where <replaceable class="parameter">from_item</replaceable> can be one 
> > of:
> >   
> > ***************
> > *** 772,778 ****
> >      <para>
> >       The <literal>FOR UPDATE</literal> clause has this form:
> >   <synopsis>
> > ! FOR UPDATE [ OF <replaceable class="parameter">table_name</replaceable> 
> > [, ...] ]
> >   </synopsis>
> >      </para>
> >   
> > --- 772,778 ----
> >      <para>
> >       The <literal>FOR UPDATE</literal> clause has this form:
> >   <synopsis>
> > ! FOR UPDATE [ OF <replaceable class="parameter">table_name</replaceable> 
> > [, ...] ] [NOWAIT]
> >   </synopsis>
> >      </para>
> >   
> > ***************
> > *** 789,796 ****
> >       has already locked a selected row or rows, <command>SELECT FOR
> >       UPDATE</command> will wait for the other transaction to complete,
> >       and will then lock and return the updated row (or no row, if the
> > !     row was deleted).  For further discussion see <xref
> > !     linkend="mvcc">.
> >      </para>
> >   
> >      <para>
> > --- 789,802 ----
> >       has already locked a selected row or rows, <command>SELECT FOR
> >       UPDATE</command> will wait for the other transaction to complete,
> >       and will then lock and return the updated row (or no row, if the
> > !     row was deleted).  If the current transaction is not supposed to
> > !     wait on other transactions to commit the NOWAIT option can be
> > !     used.  If <command>SELECT FOR UPDATE NOWAIT</command> finds out
> > !     that somebody else is holding a lock an error will be thrown.
> > !     This will only happen in case of row level locks - if somebody
> > !     holds a table lock <command>SELECT FOR UPDATE NOWAIT</command>
> > !     will still wait for concurrent transactions.  For further 
> > !     discussion see <xref linkend="mvcc">.
> >      </para>
> >   
> >      <para>
> > diff -r -c postgresql-8.0.0rc2.orig/doc/src/sgml/sql.sgml 
> > postgresql-8.0.0rc2/doc/src/sgml/sql.sgml
> > *** postgresql-8.0.0rc2.orig/doc/src/sgml/sql.sgml  Mon Nov 15 07:32:14 2004
> > --- postgresql-8.0.0rc2/doc/src/sgml/sql.sgml       Mon Dec 27 10:57:05 2004
> > ***************
> > *** 866,872 ****
> >       [ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ 
> > ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] 
> > [, ...] ]
> >       [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
> >       [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
> > !     [ FOR UPDATE [ OF <replaceable 
> > class="PARAMETER">class_name</replaceable> [, ...] ] ]
> >        </synopsis>
> >       </para>
> >   
> > --- 866,872 ----
> >       [ ORDER BY <replaceable class="PARAMETER">expression</replaceable> [ 
> > ASC | DESC | USING <replaceable class="PARAMETER">operator</replaceable> ] 
> > [, ...] ]
> >       [ LIMIT { <replaceable class="PARAMETER">count</replaceable> | ALL } ]
> >       [ OFFSET <replaceable class="PARAMETER">start</replaceable> ]
> > !     [ FOR UPDATE [ OF <replaceable 
> > class="PARAMETER">class_name</replaceable> [, ...] ] [NOWAIT] ]
> >        </synopsis>
> >       </para>
> >   
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/access/heap/heapam.c 
> > postgresql-8.0.0rc2/src/backend/access/heap/heapam.c
> > *** postgresql-8.0.0rc2.orig/src/backend/access/heap/heapam.c       Sun Nov 
> > 14 03:04:12 2004
> > --- postgresql-8.0.0rc2/src/backend/access/heap/heapam.c    Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 16,21 ****
> > --- 16,22 ----
> >    *                relation_openrv - open any relation specified by a 
> > RangeVar
> >    *                relation_openr  - open a system relation by name
> >    *                relation_close  - close any relation
> > +  *                conditional_relation_open - open with option not to wait
> >    *                heap_open               - open a heap relation by 
> > relation OID
> >    *                heap_openrv             - open a heap relation 
> > specified by a RangeVar
> >    *                heap_openr              - open a system heap relation 
> > by name
> > ***************
> > *** 1828,1834 ****
> >    */
> >   int
> >   heap_mark4update(Relation relation, HeapTuple tuple, Buffer *buffer,
> > !                            CommandId cid)
> >   {
> >     TransactionId xid = GetCurrentTransactionId();
> >     ItemPointer tid = &(tuple->t_self);
> > --- 1829,1835 ----
> >    */
> >   int
> >   heap_mark4update(Relation relation, HeapTuple tuple, Buffer *buffer,
> > !                            CommandId cid, bool nowait)
> >   {
> >     TransactionId xid = GetCurrentTransactionId();
> >     ItemPointer tid = &(tuple->t_self);
> > ***************
> > *** 1858,1866 ****
> >     {
> >             TransactionId xwait = HeapTupleHeaderGetXmax(tuple->t_data);
> >   
> > -           /* sleep until concurrent transaction ends */
> >             LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
> > !           XactLockTableWait(xwait);
> >   
> >             LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
> >             if (!TransactionIdDidCommit(xwait))
> > --- 1859,1881 ----
> >     {
> >             TransactionId xwait = HeapTupleHeaderGetXmax(tuple->t_data);
> >   
> >             LockBuffer(*buffer, BUFFER_LOCK_UNLOCK);
> > ! 
> > !           if (nowait)
> > !           {
> > !                   /* rather error than sleep until concurrent transaction 
> > ends */ 
> > !                   if (!ConditionalXactLockTableWait(xwait))
> > !                   {
> > !                           ReleaseBuffer(*buffer);
> > !                           ereport(ERROR,
> > !                                   
> > (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
> > !                                    errmsg("data in table \"%s\" was 
> > modify by concurrent trasaction.", 
> > !                                            
> > RelationGetRelationName(relation))));
> > !                   }
> > !           }
> > !           else
> > !                   /* sleep until concurrent transaction ends */
> > !                   XactLockTableWait(xwait);
> >   
> >             LockBuffer(*buffer, BUFFER_LOCK_EXCLUSIVE);
> >             if (!TransactionIdDidCommit(xwait))
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/commands/trigger.c 
> > postgresql-8.0.0rc2/src/backend/commands/trigger.c
> > *** postgresql-8.0.0rc2.orig/src/backend/commands/trigger.c Tue Dec  7 
> > 00:57:17 2004
> > --- postgresql-8.0.0rc2/src/backend/commands/trigger.c      Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 1574,1580 ****
> >             *newSlot = NULL;
> >             tuple.t_self = *tid;
> >   ltrmark:;
> > !           test = heap_mark4update(relation, &tuple, &buffer, cid);
> >             switch (test)
> >             {
> >                     case HeapTupleSelfUpdated:
> > --- 1574,1580 ----
> >             *newSlot = NULL;
> >             tuple.t_self = *tid;
> >   ltrmark:;
> > !           test = heap_mark4update(relation, &tuple, &buffer, cid, 
> > estate->es_nowait);
> >             switch (test)
> >             {
> >                     case HeapTupleSelfUpdated:
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/executor/execMain.c 
> > postgresql-8.0.0rc2/src/backend/executor/execMain.c
> > *** postgresql-8.0.0rc2.orig/src/backend/executor/execMain.c        Thu Oct 
> >  7 20:38:49 2004
> > --- postgresql-8.0.0rc2/src/backend/executor/execMain.c     Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 558,563 ****
> > --- 558,564 ----
> >     /*
> >      * Have to lock relations selected for update
> >      */
> > +   estate->es_nowait = parseTree->nowait;
> >     estate->es_rowMark = NIL;
> >     if (parseTree->rowMarks != NIL)
> >     {
> > ***************
> > *** 1133,1139 ****
> >   
> >                                     tuple.t_self = *((ItemPointer) 
> > DatumGetPointer(datum));
> >                                     test = heap_mark4update(erm->relation, 
> > &tuple, &buffer,
> > !                                                                           
> >         estate->es_snapshot->curcid);
> >                                     ReleaseBuffer(buffer);
> >                                     switch (test)
> >                                     {
> > --- 1134,1140 ----
> >   
> >                                     tuple.t_self = *((ItemPointer) 
> > DatumGetPointer(datum));
> >                                     test = heap_mark4update(erm->relation, 
> > &tuple, &buffer,
> > !                                                   
> > estate->es_snapshot->curcid, estate->es_nowait);
> >                                     ReleaseBuffer(buffer);
> >                                     switch (test)
> >                                     {
> > ***************
> > *** 2082,2087 ****
> > --- 2083,2089 ----
> >     epqstate->es_instrument = estate->es_instrument;
> >     epqstate->es_select_into = estate->es_select_into;
> >     epqstate->es_into_oids = estate->es_into_oids;
> > +   epqstate->es_nowait = estate->es_nowait;
> >     epqstate->es_topPlan = estate->es_topPlan;
> >   
> >     /*
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/executor/execUtils.c 
> > postgresql-8.0.0rc2/src/backend/executor/execUtils.c
> > *** postgresql-8.0.0rc2.orig/src/backend/executor/execUtils.c       Fri Oct 
> >  1 01:21:23 2004
> > --- postgresql-8.0.0rc2/src/backend/executor/execUtils.c    Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 203,209 ****
> >     estate->es_instrument = false;
> >     estate->es_select_into = false;
> >     estate->es_into_oids = false;
> > ! 
> >     estate->es_exprcontexts = NIL;
> >   
> >     estate->es_per_tuple_exprcontext = NULL;
> > --- 203,210 ----
> >     estate->es_instrument = false;
> >     estate->es_select_into = false;
> >     estate->es_into_oids = false;
> > !   estate->es_nowait = false;
> > !   
> >     estate->es_exprcontexts = NIL;
> >   
> >     estate->es_per_tuple_exprcontext = NULL;
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/nodes/copyfuncs.c 
> > postgresql-8.0.0rc2/src/backend/nodes/copyfuncs.c
> > *** postgresql-8.0.0rc2.orig/src/backend/nodes/copyfuncs.c  Sun Dec 12 
> > 00:26:33 2004
> > --- postgresql-8.0.0rc2/src/backend/nodes/copyfuncs.c       Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 1426,1431 ****
> > --- 1426,1442 ----
> >     return newnode;
> >   }
> >   
> > + static ForUpdate *
> > + _copyForUpdate(ForUpdate *from)
> > + {
> > +   ForUpdate *newnode = makeNode(ForUpdate);
> > + 
> > +   COPY_NODE_FIELD(update_list);
> > +   COPY_SCALAR_FIELD(nowait);
> > + 
> > +   return newnode;
> > + }
> > + 
> >   static RangeSubselect *
> >   _copyRangeSubselect(RangeSubselect *from)
> >   {
> > ***************
> > *** 1537,1542 ****
> > --- 1548,1554 ----
> >     COPY_NODE_FIELD(groupClause);
> >     COPY_NODE_FIELD(havingQual);
> >     COPY_NODE_FIELD(distinctClause);
> > +   COPY_SCALAR_FIELD(nowait);
> >     COPY_NODE_FIELD(sortClause);
> >     COPY_NODE_FIELD(limitOffset);
> >     COPY_NODE_FIELD(limitCount);
> > ***************
> > *** 1611,1617 ****
> >     COPY_NODE_FIELD(sortClause);
> >     COPY_NODE_FIELD(limitOffset);
> >     COPY_NODE_FIELD(limitCount);
> > !   COPY_NODE_FIELD(forUpdate);
> >     COPY_SCALAR_FIELD(op);
> >     COPY_SCALAR_FIELD(all);
> >     COPY_NODE_FIELD(larg);
> > --- 1623,1629 ----
> >     COPY_NODE_FIELD(sortClause);
> >     COPY_NODE_FIELD(limitOffset);
> >     COPY_NODE_FIELD(limitCount);
> > !   COPY_NODE_FIELD(forupdateClause);
> >     COPY_SCALAR_FIELD(op);
> >     COPY_SCALAR_FIELD(all);
> >     COPY_NODE_FIELD(larg);
> > ***************
> > *** 3065,3070 ****
> > --- 3077,3085 ----
> >             case T_SortBy:
> >                     retval = _copySortBy(from);
> >                     break;
> > +           case T_ForUpdate:
> > +                   retval = _copyForUpdate(from);
> > +                   break;
> >             case T_RangeSubselect:
> >                     retval = _copyRangeSubselect(from);
> >                     break;
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/nodes/equalfuncs.c 
> > postgresql-8.0.0rc2/src/backend/nodes/equalfuncs.c
> > *** postgresql-8.0.0rc2.orig/src/backend/nodes/equalfuncs.c Sun Dec 12 
> > 00:26:33 2004
> > --- postgresql-8.0.0rc2/src/backend/nodes/equalfuncs.c      Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 656,661 ****
> > --- 656,662 ----
> >     COMPARE_NODE_FIELD(groupClause);
> >     COMPARE_NODE_FIELD(havingQual);
> >     COMPARE_NODE_FIELD(distinctClause);
> > +   COMPARE_SCALAR_FIELD(nowait);
> >     COMPARE_NODE_FIELD(sortClause);
> >     COMPARE_NODE_FIELD(limitOffset);
> >     COMPARE_NODE_FIELD(limitCount);
> > ***************
> > *** 719,725 ****
> >     COMPARE_NODE_FIELD(sortClause);
> >     COMPARE_NODE_FIELD(limitOffset);
> >     COMPARE_NODE_FIELD(limitCount);
> > !   COMPARE_NODE_FIELD(forUpdate);
> >     COMPARE_SCALAR_FIELD(op);
> >     COMPARE_SCALAR_FIELD(all);
> >     COMPARE_NODE_FIELD(larg);
> > --- 720,726 ----
> >     COMPARE_NODE_FIELD(sortClause);
> >     COMPARE_NODE_FIELD(limitOffset);
> >     COMPARE_NODE_FIELD(limitCount);
> > !   COMPARE_NODE_FIELD(forupdateClause);
> >     COMPARE_SCALAR_FIELD(op);
> >     COMPARE_SCALAR_FIELD(all);
> >     COMPARE_NODE_FIELD(larg);
> > ***************
> > *** 1577,1582 ****
> > --- 1578,1592 ----
> >   }
> >   
> >   static bool
> > + _equalForUpdate(ForUpdate *a, ForUpdate *b)
> > + {
> > +   COMPARE_SCALAR_FIELD(nowait);
> > +   COMPARE_NODE_FIELD(update_list);
> > + 
> > +   return true;
> > + }
> > + 
> > + static bool
> >   _equalRangeSubselect(RangeSubselect *a, RangeSubselect *b)
> >   {
> >     COMPARE_NODE_FIELD(subquery);
> > ***************
> > *** 2202,2207 ****
> > --- 2212,2220 ----
> >             case T_SortBy:
> >                     retval = _equalSortBy(a, b);
> >                     break;
> > +           case T_ForUpdate:
> > +                   retval = _equalForUpdate(a, b);
> > +                   break;
> >             case T_RangeSubselect:
> >                     retval = _equalRangeSubselect(a, b);
> >                     break;
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/nodes/outfuncs.c 
> > postgresql-8.0.0rc2/src/backend/nodes/outfuncs.c
> > *** postgresql-8.0.0rc2.orig/src/backend/nodes/outfuncs.c   Sun Dec 12 
> > 00:26:33 2004
> > --- postgresql-8.0.0rc2/src/backend/nodes/outfuncs.c        Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 1202,1208 ****
> >     WRITE_NODE_FIELD(sortClause);
> >     WRITE_NODE_FIELD(limitOffset);
> >     WRITE_NODE_FIELD(limitCount);
> > !   WRITE_NODE_FIELD(forUpdate);
> >     WRITE_ENUM_FIELD(op, SetOperation);
> >     WRITE_BOOL_FIELD(all);
> >     WRITE_NODE_FIELD(larg);
> > --- 1202,1208 ----
> >     WRITE_NODE_FIELD(sortClause);
> >     WRITE_NODE_FIELD(limitOffset);
> >     WRITE_NODE_FIELD(limitCount);
> > !   WRITE_NODE_FIELD(forupdateClause);
> >     WRITE_ENUM_FIELD(op, SetOperation);
> >     WRITE_BOOL_FIELD(all);
> >     WRITE_NODE_FIELD(larg);
> > ***************
> > *** 1323,1328 ****
> > --- 1323,1329 ----
> >     WRITE_NODE_FIELD(groupClause);
> >     WRITE_NODE_FIELD(havingQual);
> >     WRITE_NODE_FIELD(distinctClause);
> > +   WRITE_BOOL_FIELD(nowait);
> >     WRITE_NODE_FIELD(sortClause);
> >     WRITE_NODE_FIELD(limitOffset);
> >     WRITE_NODE_FIELD(limitCount);
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/nodes/readfuncs.c 
> > postgresql-8.0.0rc2/src/backend/nodes/readfuncs.c
> > *** postgresql-8.0.0rc2.orig/src/backend/nodes/readfuncs.c  Sun Dec 12 
> > 00:26:34 2004
> > --- postgresql-8.0.0rc2/src/backend/nodes/readfuncs.c       Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 149,154 ****
> > --- 149,155 ----
> >     READ_NODE_FIELD(groupClause);
> >     READ_NODE_FIELD(havingQual);
> >     READ_NODE_FIELD(distinctClause);
> > +   READ_BOOL_FIELD(nowait);
> >     READ_NODE_FIELD(sortClause);
> >     READ_NODE_FIELD(limitOffset);
> >     READ_NODE_FIELD(limitCount);
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/parser/analyze.c 
> > postgresql-8.0.0rc2/src/backend/parser/analyze.c
> > *** postgresql-8.0.0rc2.orig/src/backend/parser/analyze.c   Wed Nov 17 
> > 00:34:26 2004
> > --- postgresql-8.0.0rc2/src/backend/parser/analyze.c        Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 135,141 ****
> >                                        bool isAddConstraint);
> >   static void applyColumnNames(List *dst, List *src);
> >   static List *getSetColTypes(ParseState *pstate, Node *node);
> > ! static void transformForUpdate(Query *qry, List *forUpdate);
> >   static void transformConstraintAttrs(List *constraintList);
> >   static void transformColumnType(ParseState *pstate, ColumnDef *column);
> >   static void release_pstate_resources(ParseState *pstate);
> > --- 135,141 ----
> >                                        bool isAddConstraint);
> >   static void applyColumnNames(List *dst, List *src);
> >   static List *getSetColTypes(ParseState *pstate, Node *node);
> > ! static void transformForUpdate(Query *qry, Node *forupdateClause);
> >   static void transformConstraintAttrs(List *constraintList);
> >   static void transformColumnType(ParseState *pstate, ColumnDef *column);
> >   static void release_pstate_resources(ParseState *pstate);
> > ***************
> > *** 1804,1810 ****
> >     qry->commandType = CMD_SELECT;
> >   
> >     /* make FOR UPDATE clause available to addRangeTableEntry */
> > !   pstate->p_forUpdate = stmt->forUpdate;
> >   
> >     /* process the FROM clause */
> >     transformFromClause(pstate, stmt->fromClause);
> > --- 1804,1810 ----
> >     qry->commandType = CMD_SELECT;
> >   
> >     /* make FOR UPDATE clause available to addRangeTableEntry */
> > !   pstate->p_forUpdate = stmt->forupdateClause ? ((ForUpdate 
> > *)stmt->forupdateClause)->update_list : NIL;
> >   
> >     /* process the FROM clause */
> >     transformFromClause(pstate, stmt->fromClause);
> > ***************
> > *** 1864,1871 ****
> >     if (pstate->p_hasAggs || qry->groupClause)
> >             parseCheckAggregates(pstate, qry);
> >   
> > !   if (stmt->forUpdate != NIL)
> > !           transformForUpdate(qry, stmt->forUpdate);
> >   
> >     return qry;
> >   }
> > --- 1864,1871 ----
> >     if (pstate->p_hasAggs || qry->groupClause)
> >             parseCheckAggregates(pstate, qry);
> >   
> > !   if (stmt->forupdateClause)
> > !           transformForUpdate(qry, stmt->forupdateClause);
> >   
> >     return qry;
> >   }
> > ***************
> > *** 1893,1899 ****
> >     List       *sortClause;
> >     Node       *limitOffset;
> >     Node       *limitCount;
> > !   List       *forUpdate;
> >     Node       *node;
> >     ListCell   *left_tlist,
> >                        *dtlist;
> > --- 1893,1899 ----
> >     List       *sortClause;
> >     Node       *limitOffset;
> >     Node       *limitCount;
> > !   Node       *forUpdate;
> >     Node       *node;
> >     ListCell   *left_tlist,
> >                        *dtlist;
> > ***************
> > *** 1931,1942 ****
> >     sortClause = stmt->sortClause;
> >     limitOffset = stmt->limitOffset;
> >     limitCount = stmt->limitCount;
> > !   forUpdate = stmt->forUpdate;
> >   
> >     stmt->sortClause = NIL;
> >     stmt->limitOffset = NULL;
> >     stmt->limitCount = NULL;
> > !   stmt->forUpdate = NIL;
> >   
> >     /* We don't support forUpdate with set ops at the moment. */
> >     if (forUpdate)
> > --- 1931,1942 ----
> >     sortClause = stmt->sortClause;
> >     limitOffset = stmt->limitOffset;
> >     limitCount = stmt->limitCount;
> > !   forUpdate = stmt->forupdateClause;
> >   
> >     stmt->sortClause = NIL;
> >     stmt->limitOffset = NULL;
> >     stmt->limitCount = NULL;
> > !   stmt->forupdateClause = NULL;
> >   
> >     /* We don't support forUpdate with set ops at the moment. */
> >     if (forUpdate)
> > ***************
> > *** 2080,2086 ****
> >     if (pstate->p_hasAggs || qry->groupClause)
> >             parseCheckAggregates(pstate, qry);
> >   
> > !   if (forUpdate != NIL)
> >             transformForUpdate(qry, forUpdate);
> >   
> >     return qry;
> > --- 2080,2086 ----
> >     if (pstate->p_hasAggs || qry->groupClause)
> >             parseCheckAggregates(pstate, qry);
> >   
> > !   if (forUpdate)
> >             transformForUpdate(qry, forUpdate);
> >   
> >     return qry;
> > ***************
> > *** 2105,2111 ****
> >                             (errcode(ERRCODE_SYNTAX_ERROR),
> >                              errmsg("INTO is only allowed on first SELECT 
> > of UNION/INTERSECT/EXCEPT")));
> >     /* We don't support forUpdate with set ops at the moment. */
> > !   if (stmt->forUpdate)
> >             ereport(ERROR,
> >                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> >                              errmsg("SELECT FOR UPDATE is not allowed with 
> > UNION/INTERSECT/EXCEPT")));
> > --- 2105,2111 ----
> >                             (errcode(ERRCODE_SYNTAX_ERROR),
> >                              errmsg("INTO is only allowed on first SELECT 
> > of UNION/INTERSECT/EXCEPT")));
> >     /* We don't support forUpdate with set ops at the moment. */
> > !   if (stmt->forupdateClause)
> >             ereport(ERROR,
> >                             (errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
> >                              errmsg("SELECT FOR UPDATE is not allowed with 
> > UNION/INTERSECT/EXCEPT")));
> > ***************
> > *** 2125,2131 ****
> >     {
> >             Assert(stmt->larg != NULL && stmt->rarg != NULL);
> >             if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
> > !                   stmt->forUpdate)
> >                     isLeaf = true;
> >             else
> >                     isLeaf = false;
> > --- 2125,2131 ----
> >     {
> >             Assert(stmt->larg != NULL && stmt->rarg != NULL);
> >             if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
> > !                   stmt->forupdateClause)
> >                     isLeaf = true;
> >             else
> >                     isLeaf = false;
> > ***************
> > *** 2737,2752 ****
> >    * in rewriteHandler.c.
> >    */
> >   static void
> > ! transformForUpdate(Query *qry, List *forUpdate)
> >   {
> >     List       *rowMarks = qry->rowMarks;
> >     ListCell   *l;
> >     ListCell   *rt;
> > !   Index           i;
> >   
> >     CheckSelectForUpdate(qry);
> >   
> > !   if (linitial(forUpdate) == NULL)
> >     {
> >             /* all regular tables used in query */
> >             i = 0;
> > --- 2737,2761 ----
> >    * in rewriteHandler.c.
> >    */
> >   static void
> > ! transformForUpdate(Query *qry, Node *forupdateClause)
> >   {
> >     List       *rowMarks = qry->rowMarks;
> >     ListCell   *l;
> >     ListCell   *rt;
> > !   Index      i;
> > !   ForUpdate  *fu = (ForUpdate *) forupdateClause;
> > !   ForUpdate  empty;
> > !   List       *update_list;
> >   
> >     CheckSelectForUpdate(qry);
> >   
> > !   update_list = fu->update_list;
> > !   qry->nowait = fu->nowait;
> > ! 
> > !   memset(&empty, 0, sizeof(ForUpdate));
> > !   empty.nowait = FALSE;
> > !   
> > !   if (linitial(update_list) == NULL)
> >     {
> >             /* all regular tables used in query */
> >             i = 0;
> > ***************
> > *** 2768,2774 ****
> >                                      * FOR UPDATE of subquery is propagated 
> > to subquery's
> >                                      * rels
> >                                      */
> > !                                   transformForUpdate(rte->subquery, 
> > list_make1(NULL));
> >                                     break;
> >                             default:
> >                                     /* ignore JOIN, SPECIAL, FUNCTION RTEs 
> > */
> > --- 2777,2785 ----
> >                                      * FOR UPDATE of subquery is propagated 
> > to subquery's
> >                                      * rels
> >                                      */
> > !                                   empty.update_list = list_make1(NULL);
> > !                                   transformForUpdate(rte->subquery, (Node 
> > *) &empty);
> > !                                   empty.update_list = NIL;
> >                                     break;
> >                             default:
> >                                     /* ignore JOIN, SPECIAL, FUNCTION RTEs 
> > */
> > ***************
> > *** 2779,2785 ****
> >     else
> >     {
> >             /* just the named tables */
> > !           foreach(l, forUpdate)
> >             {
> >                     char       *relname = strVal(lfirst(l));
> >   
> > --- 2790,2796 ----
> >     else
> >     {
> >             /* just the named tables */
> > !           foreach(l, update_list)
> >             {
> >                     char       *relname = strVal(lfirst(l));
> >   
> > ***************
> > *** 2804,2810 ****
> >                                                      * FOR UPDATE of 
> > subquery is propagated to
> >                                                      * subquery's rels
> >                                                      */
> > !                                                   
> > transformForUpdate(rte->subquery, list_make1(NULL));
> >                                                     break;
> >                                             case RTE_JOIN:
> >                                                     ereport(ERROR,
> > --- 2815,2823 ----
> >                                                      * FOR UPDATE of 
> > subquery is propagated to
> >                                                      * subquery's rels
> >                                                      */
> > !                                                   empty.update_list = 
> > list_make1(NULL);
> > !                                                   
> > transformForUpdate(rte->subquery, (Node *) &empty);
> > !                                                   empty.update_list = 
> > NULL;
> >                                                     break;
> >                                             case RTE_JOIN:
> >                                                     ereport(ERROR,
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/parser/gram.y 
> > postgresql-8.0.0rc2/src/backend/parser/gram.y
> > *** postgresql-8.0.0rc2.orig/src/backend/parser/gram.y      Mon Nov  8 
> > 05:02:20 2004
> > --- postgresql-8.0.0rc2/src/backend/parser/gram.y   Mon Dec 27 10:56:52 2004
> > ***************
> > *** 87,93 ****
> >   static List *extractArgTypes(List *parameters);
> >   static SelectStmt *findLeftmostSelect(SelectStmt *node);
> >   static void insertSelectOptions(SelectStmt *stmt,
> > !                                                           List 
> > *sortClause, List *forUpdate,
> >                                                             Node 
> > *limitOffset, Node *limitCount);
> >   static Node *makeSetOp(SetOperation op, bool all, Node *larg, Node *rarg);
> >   static Node *doNegate(Node *n);
> > --- 87,93 ----
> >   static List *extractArgTypes(List *parameters);
> >   static SelectStmt *findLeftmostSelect(SelectStmt *node);
> >   static void insertSelectOptions(SelectStmt *stmt,
> > !                                                           List 
> > *sortClause, Node *forUpdate,
> >                                                             Node 
> > *limitOffset, Node *limitCount);
> >   static Node *makeSetOp(SetOperation op, bool all, Node *larg, Node *rarg);
> >   static Node *doNegate(Node *n);
> > ***************
> > *** 239,245 ****
> >   %type <oncommit> OnCommitOption
> >   %type <withoids> OptWithOids WithOidsAs
> >   
> > ! %type <list>      for_update_clause opt_for_update_clause update_list
> >   %type <boolean>   opt_all
> >   
> >   %type <node>      join_outer join_qual
> > --- 239,247 ----
> >   %type <oncommit> OnCommitOption
> >   %type <withoids> OptWithOids WithOidsAs
> >   
> > ! %type <node>      for_update_clause opt_for_update_clause
> > ! %type <list>      update_list
> > ! 
> >   %type <boolean>   opt_all
> >   
> >   %type <node>      join_outer join_qual
> > ***************
> > *** 4801,4807 ****
> >                     simple_select                                           
> > { $$ = $1; }
> >                     | select_clause sort_clause
> >                             {
> > !                                   insertSelectOptions((SelectStmt *) $1, 
> > $2, NIL,
> >                                                                             
> > NULL, NULL);
> >                                     $$ = $1;
> >                             }
> > --- 4803,4809 ----
> >                     simple_select                                           
> > { $$ = $1; }
> >                     | select_clause sort_clause
> >                             {
> > !                                   insertSelectOptions((SelectStmt *) $1, 
> > $2, NULL,
> >                                                                             
> > NULL, NULL);
> >                                     $$ = $1;
> >                             }
> > ***************
> > *** 4862,4867 ****
> > --- 4864,4870 ----
> >                                     n->whereClause = $6;
> >                                     n->groupClause = $7;
> >                                     n->havingClause = $8;
> > +                                   n->forupdateClause = NULL;
> >                                     $$ = (Node *)n;
> >                             }
> >                     | select_clause UNION opt_all select_clause
> > ***************
> > *** 5053,5060 ****
> >             ;
> >   
> >   for_update_clause:
> > !                   FOR UPDATE update_list                                  
> > { $$ = $3; }
> > !                   | FOR READ ONLY                                         
> >         { $$ = NULL; }
> >             ;
> >   
> >   opt_for_update_clause:
> > --- 5056,5069 ----
> >             ;
> >   
> >   for_update_clause:
> > !                   FOR UPDATE update_list opt_nowait       
> > !                           { 
> > !                                   ForUpdate *n = makeNode(ForUpdate);
> > !                                   n->update_list = $3;
> > !                                   n->nowait = $4;
> > !                                   $$ = (Node *) n;
> > !                           }
> > !                   | FOR READ ONLY                                         
> >         { $$ = NULL; }  
> >             ;
> >   
> >   opt_for_update_clause:
> > ***************
> > *** 8284,8290 ****
> >    */
> >   static void
> >   insertSelectOptions(SelectStmt *stmt,
> > !                                   List *sortClause, List *forUpdate,
> >                                     Node *limitOffset, Node *limitCount)
> >   {
> >     /*
> > --- 8293,8299 ----
> >    */
> >   static void
> >   insertSelectOptions(SelectStmt *stmt,
> > !                                   List *sortClause, Node *forUpdate,
> >                                     Node *limitOffset, Node *limitCount)
> >   {
> >     /*
> > ***************
> > *** 8301,8311 ****
> >     }
> >     if (forUpdate)
> >     {
> > !           if (stmt->forUpdate)
> >                     ereport(ERROR,
> >                                     (errcode(ERRCODE_SYNTAX_ERROR),
> >                                      errmsg("multiple FOR UPDATE clauses 
> > not allowed")));
> > !           stmt->forUpdate = forUpdate;
> >     }
> >     if (limitOffset)
> >     {
> > --- 8310,8320 ----
> >     }
> >     if (forUpdate)
> >     {
> > !           if (stmt->forupdateClause)
> >                     ereport(ERROR,
> >                                     (errcode(ERRCODE_SYNTAX_ERROR),
> >                                      errmsg("multiple FOR UPDATE clauses 
> > not allowed")));
> > !           stmt->forupdateClause = forUpdate;
> >     }
> >     if (limitOffset)
> >     {
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/parser/parse_type.c 
> > postgresql-8.0.0rc2/src/backend/parser/parse_type.c
> > *** postgresql-8.0.0rc2.orig/src/backend/parser/parse_type.c        Wed Dec 
> > 15 21:15:17 2004
> > --- postgresql-8.0.0rc2/src/backend/parser/parse_type.c     Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 432,438 ****
> >             stmt->sortClause != NIL ||
> >             stmt->limitOffset != NULL ||
> >             stmt->limitCount != NULL ||
> > !           stmt->forUpdate != NIL ||
> >             stmt->op != SETOP_NONE)
> >             goto fail;
> >     if (list_length(stmt->targetList) != 1)
> > --- 432,438 ----
> >             stmt->sortClause != NIL ||
> >             stmt->limitOffset != NULL ||
> >             stmt->limitCount != NULL ||
> > !           stmt->forupdateClause != NULL ||
> >             stmt->op != SETOP_NONE)
> >             goto fail;
> >     if (list_length(stmt->targetList) != 1)
> > diff -r -c postgresql-8.0.0rc2.orig/src/backend/storage/lmgr/lmgr.c 
> > postgresql-8.0.0rc2/src/backend/storage/lmgr/lmgr.c
> > *** postgresql-8.0.0rc2.orig/src/backend/storage/lmgr/lmgr.c        Thu Sep 
> > 16 18:58:33 2004
> > --- postgresql-8.0.0rc2/src/backend/storage/lmgr/lmgr.c     Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 393,395 ****
> > --- 393,435 ----
> >     if (!TransactionIdDidCommit(xid) && !TransactionIdDidAbort(xid))
> >             TransactionIdAbort(xid);
> >   }
> > + 
> > + /*
> > +  * As above, but only lock if we can get the lock without blocking.
> > +  * Returns TRUE if the lock was acquired. 
> > +  */
> > + bool
> > + ConditionalXactLockTableWait(TransactionId xid)
> > + {
> > +   LOCKTAG         tag;
> > +   TransactionId myxid = GetTopTransactionId();
> > + 
> > +   for (;;)
> > +   {
> > +           Assert(TransactionIdIsValid(xid));
> > +           Assert(!TransactionIdEquals(xid, myxid));
> > + 
> > +           MemSet(&tag, 0, sizeof(tag));
> > +           tag.relId = XactLockTableId;
> > +           tag.dbId = InvalidOid;
> > +           tag.objId.xid = xid;
> > + 
> > +           if (!LockAcquire(LockTableId, &tag, myxid, ShareLock, true))
> > +                   return FALSE;
> > +           LockRelease(LockTableId, &tag, myxid, ShareLock);
> > + 
> > +           if (!TransactionIdIsInProgress(xid))
> > +                   break;
> > +           xid = SubTransGetParent(xid);
> > +   }
> > + 
> > +   /*
> > +    * Transaction was committed/aborted/crashed - we have to update
> > +    * pg_clog if transaction is still marked as running.
> > +    */
> > +   if (!TransactionIdDidCommit(xid) && !TransactionIdDidAbort(xid))
> > +           TransactionIdAbort(xid);
> > +   
> > +   return TRUE;
> > + }
> > + 
> > diff -r -c postgresql-8.0.0rc2.orig/src/bin/psql/sql_help.h 
> > postgresql-8.0.0rc2/src/bin/psql/sql_help.h
> > *** postgresql-8.0.0rc2.orig/src/bin/psql/sql_help.h        Tue Dec 21 
> > 05:22:44 2004
> > --- postgresql-8.0.0rc2/src/bin/psql/sql_help.h     Mon Dec 27 10:57:05 2004
> > ***************
> > *** 383,393 ****
> >   
> >       { "SELECT",
> >         N_("retrieve rows from a table or view"),
> > !       N_("SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]\n    * 
> > | expression [ AS output_name ] [, ...]\n    [ FROM from_item [, ...] ]\n   
> >  [ WHERE condition ]\n    [ GROUP BY expression [, ...] ]\n    [ HAVING 
> > condition [, ...] ]\n    [ { UNION | INTERSECT | EXCEPT } [ ALL ] select 
> > ]\n    [ ORDER BY expression [ ASC | DESC | USING operator ] [, ...] ]\n    
> > [ LIMIT { count | ALL } ]\n    [ OFFSET start ]\n    [ FOR UPDATE [ OF 
> > table_name [, ...] ] ]\n\nwhere from_item can be one of:\n\n    [ ONLY ] 
> > table_name [ * ] [ [ AS ] alias [ ( column_alias [, ...] ) ] ]\n    ( 
> > select ) [ AS ] alias [ ( column_alias [, ...] ) ]\n    function_name ( [ 
> > argument [, ...] ] ) [ AS ] alias [ ( column_alias [, ...] | 
> > column_definition [, ...] ) ]\n    function_name ( [ argument [, ...] ] ) 
> > AS ( column_definition [, ...] )\n    from_item [ NATURAL ] join_type 
> > from_item [ ON join_condition | USING ( join_column [, ...] ) ]") },
> >   
> >       { "SELECT INTO",
> >         N_("define a new table from the results of a query"),
> > !       N_("SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]\n    * 
> > | expression [ AS output_name ] [, ...]\n    INTO [ TEMPORARY | TEMP ] [ 
> > TABLE ] new_table\n    [ FROM from_item [, ...] ]\n    [ WHERE condition 
> > ]\n    [ GROUP BY expression [, ...] ]\n    [ HAVING condition [, ...] ]\n  
> >   [ { UNION | INTERSECT | EXCEPT } [ ALL ] select ]\n    [ ORDER BY 
> > expression [ ASC | DESC | USING operator ] [, ...] ]\n    [ LIMIT { count | 
> > ALL } ]\n    [ OFFSET start ]\n    [ FOR UPDATE [ OF tablename [, ...] ] 
> > ]") },
> >   
> >       { "SET",
> >         N_("change a run-time parameter"),
> > --- 383,393 ----
> >   
> >       { "SELECT",
> >         N_("retrieve rows from a table or view"),
> > !       N_("SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]\n    * 
> > | expression [ AS output_name ] [, ...]\n    [ FROM from_item [, ...] ]\n   
> >  [ WHERE condition ]\n    [ GROUP BY expression [, ...] ]\n    [ HAVING 
> > condition [, ...] ]\n    [ { UNION | INTERSECT | EXCEPT } [ ALL ] select 
> > ]\n    [ ORDER BY expression [ ASC | DESC | USING operator ] [, ...] ]\n    
> > [ LIMIT { count | ALL } ]\n    [ OFFSET start ]\n    [ FOR UPDATE [ OF 
> > table_name [, ...] ] [NOWAIT] ]\n\nwhere from_item can be one of:\n\n    [ 
> > ONLY ] table_name [ * ] [ [ AS ] alias [ ( column_alias [, ...] ) ] ]\n    
> > ( select ) [ AS ] alias [ ( column_alias [, ...] ) ]\n    function_name ( [ 
> > argument [, ...] ] ) [ AS ] alias [ ( column_alias [, ...] | 
> > column_definition [, ...] ) ]\n    function_name ( [ argument [, ...] ] ) 
> > AS ( column_definition [, ...] )\n    from_item [ NATURAL ] join_type 
> > from_item [ ON join_condition | USING ( join_column [, ...] ) ]") },
> >   
> >       { "SELECT INTO",
> >         N_("define a new table from the results of a query"),
> > !       N_("SELECT [ ALL | DISTINCT [ ON ( expression [, ...] ) ] ]\n    * 
> > | expression [ AS output_name ] [, ...]\n    INTO [ TEMPORARY | TEMP ] [ 
> > TABLE ] new_table\n    [ FROM from_item [, ...] ]\n    [ WHERE condition 
> > ]\n    [ GROUP BY expression [, ...] ]\n    [ HAVING condition [, ...] ]\n  
> >   [ { UNION | INTERSECT | EXCEPT } [ ALL ] select ]\n    [ ORDER BY 
> > expression [ ASC | DESC | USING operator ] [, ...] ]\n    [ LIMIT { count | 
> > ALL } ]\n    [ OFFSET start ]\n    [ FOR UPDATE [ OF tablename [, ...] ] 
> > [NOWAIT] ]") },
> >   
> >       { "SET",
> >         N_("change a run-time parameter"),
> > diff -r -c postgresql-8.0.0rc2.orig/src/include/access/heapam.h 
> > postgresql-8.0.0rc2/src/include/access/heapam.h
> > *** postgresql-8.0.0rc2.orig/src/include/access/heapam.h    Sun Aug 29 
> > 07:06:55 2004
> > --- postgresql-8.0.0rc2/src/include/access/heapam.h Mon Dec 27 10:57:05 2004
> > ***************
> > *** 164,170 ****
> >   extern int heap_update(Relation relation, ItemPointer otid, HeapTuple tup,
> >             ItemPointer ctid, CommandId cid, Snapshot crosscheck, bool 
> > wait);
> >   extern int heap_mark4update(Relation relation, HeapTuple tup,
> > !                            Buffer *userbuf, CommandId cid);
> >   
> >   extern Oid        simple_heap_insert(Relation relation, HeapTuple tup);
> >   extern void simple_heap_delete(Relation relation, ItemPointer tid);
> > --- 164,170 ----
> >   extern int heap_update(Relation relation, ItemPointer otid, HeapTuple tup,
> >             ItemPointer ctid, CommandId cid, Snapshot crosscheck, bool 
> > wait);
> >   extern int heap_mark4update(Relation relation, HeapTuple tup,
> > !                            Buffer *userbuf, CommandId cid, bool nowait);
> >   
> >   extern Oid        simple_heap_insert(Relation relation, HeapTuple tup);
> >   extern void simple_heap_delete(Relation relation, ItemPointer tid);
> > diff -r -c postgresql-8.0.0rc2.orig/src/include/nodes/execnodes.h 
> > postgresql-8.0.0rc2/src/include/nodes/execnodes.h
> > *** postgresql-8.0.0rc2.orig/src/include/nodes/execnodes.h  Sun Dec 12 
> > 00:26:49 2004
> > --- postgresql-8.0.0rc2/src/include/nodes/execnodes.h       Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 308,313 ****
> > --- 308,314 ----
> >     bool            es_instrument;  /* true requests runtime 
> > instrumentation */
> >     bool            es_select_into; /* true if doing SELECT INTO */
> >     bool            es_into_oids;   /* true to generate OIDs in SELECT INTO 
> > */
> > +   bool            es_nowait;      /* SELECT FOR UPDATE NOWAIT */
> >   
> >     List       *es_exprcontexts;    /* List of ExprContexts within EState */
> >   
> > diff -r -c postgresql-8.0.0rc2.orig/src/include/nodes/nodes.h 
> > postgresql-8.0.0rc2/src/include/nodes/nodes.h
> > *** postgresql-8.0.0rc2.orig/src/include/nodes/nodes.h      Sun Dec 12 
> > 00:26:49 2004
> > --- postgresql-8.0.0rc2/src/include/nodes/nodes.h   Mon Dec 27 10:56:52 2004
> > ***************
> > *** 302,307 ****
> > --- 302,308 ----
> >     T_CompositeTypeStmt,
> >     T_InhRelation,
> >     T_FunctionParameter,
> > +   T_ForUpdate,
> >   
> >     /*
> >      * TAGS FOR FUNCTION-CALL CONTEXT AND RESULTINFO NODES (see fmgr.h)
> > diff -r -c postgresql-8.0.0rc2.orig/src/include/nodes/parsenodes.h 
> > postgresql-8.0.0rc2/src/include/nodes/parsenodes.h
> > *** postgresql-8.0.0rc2.orig/src/include/nodes/parsenodes.h Fri Nov  5 
> > 20:16:38 2004
> > --- postgresql-8.0.0rc2/src/include/nodes/parsenodes.h      Mon Dec 27 
> > 10:56:52 2004
> > ***************
> > *** 103,108 ****
> > --- 103,110 ----
> >   
> >     List       *sortClause;         /* a list of SortClause's */
> >   
> > +   bool       nowait;              /* are we in NOWAIT mode? */
> > + 
> >     Node       *limitOffset;        /* # of result tuples to skip */
> >     Node       *limitCount;         /* # of result tuples to return */
> >   
> > ***************
> > *** 422,427 ****
> > --- 424,439 ----
> >     Node       *arg;                        /* a (Value *) or a (TypeName 
> > *) */
> >   } DefElem;
> >   
> > + /*
> > +  * ForUpdate -
> > +  *       used in raw parsetrees output only
> > +  */
> > + typedef struct ForUpdate
> > + {
> > +   NodeTag         type;
> > +   List            *update_list;   /* list of tables */
> > +   bool            nowait;         /* NOWAIT option */
> > + } ForUpdate;
> >   
> >   
> > /****************************************************************************
> >    *        Nodes for a Query tree
> > ***************
> > *** 686,692 ****
> >     List       *sortClause;         /* sort clause (a list of SortBy's) */
> >     Node       *limitOffset;        /* # of result tuples to skip */
> >     Node       *limitCount;         /* # of result tuples to return */
> > !   List       *forUpdate;          /* FOR UPDATE clause */
> >   
> >     /*
> >      * These fields are used only in upper-level SelectStmts.
> > --- 698,704 ----
> >     List       *sortClause;         /* sort clause (a list of SortBy's) */
> >     Node       *limitOffset;        /* # of result tuples to skip */
> >     Node       *limitCount;         /* # of result tuples to return */
> > !   Node       *forupdateClause;    /* FOR UPDATE clause (ForUpdate node) */
> >   
> >     /*
> >      * These fields are used only in upper-level SelectStmts.
> > diff -r -c postgresql-8.0.0rc2.orig/src/include/storage/lmgr.h 
> > postgresql-8.0.0rc2/src/include/storage/lmgr.h
> > *** postgresql-8.0.0rc2.orig/src/include/storage/lmgr.h     Thu Sep 16 
> > 18:58:42 2004
> > --- postgresql-8.0.0rc2/src/include/storage/lmgr.h  Mon Dec 27 10:56:52 2004
> > ***************
> > *** 60,64 ****
> > --- 60,65 ----
> >   extern void XactLockTableInsert(TransactionId xid);
> >   extern void XactLockTableDelete(TransactionId xid);
> >   extern void XactLockTableWait(TransactionId xid);
> > + extern bool ConditionalXactLockTableWait(TransactionId xid);
> >   
> >   #endif   /* LMGR_H */
> 
> -- 
>   Bruce Momjian                        |  http://candle.pha.pa.us
>   pgman@candle.pha.pa.us               |  (610) 359-1001
>   +  If your life is a hard drive,     |  13 Roberts Road
>   +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073
> 
> ---------------------------(end of broadcast)---------------------------
> TIP 4: Don't 'kill -9' the postmaster
> 

-- 
  Bruce Momjian                        |  http://candle.pha.pa.us
  pgman@candle.pha.pa.us               |  (610) 359-1001
  +  If your life is a hard drive,     |  13 Roberts Road
  +  Christ can be your backup.        |  Newtown Square, Pennsylvania 19073

---------------------------(end of broadcast)---------------------------
TIP 9: In versions below 8.0, the planner will ignore your desire to
       choose an index scan if your joining column's datatypes do not
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