Re: Implementing SELECT FOR UPDATE [NOWAIT]

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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(at)candle(dot)pha(dot)pa(dot)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(at)candle(dot)pha(dot)pa(dot)us | (610) 359-1001
+ If your life is a hard drive, | 13 Roberts Road
+ Christ can be your backup. | Newtown Square, Pennsylvania 19073