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Make SELECT FOR UPDATE/SHARE work on inheritance trees, by having the plan 

return the tableoid as well as the ctid for any FOR UPDATE targets that
have child tables.  All child tables are listed in the ExecRowMark list,
but the executor just skips the ones that didn't produce the current row.

Curiously, this longstanding restriction doesn't seem to have been documented
anywhere; so no doc changes.
This commit is contained in:
Tom Lane 2008-11-15 19:43:47 +00:00
parent 07c179a82b
commit 0656ed3daa
15 changed files with 150 additions and 41 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
src/backend/executor/execMain.c
View File

@ -26,7 +26,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.315 2008/11/06 20:51:14 tgl Exp $
* $PostgreSQL: pgsql/src/backend/executor/execMain.c,v 1.316 2008/11/15 19:43:45 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -590,18 +590,25 @@ InitPlan(QueryDesc *queryDesc, int eflags)
foreach(l, plannedstmt->rowMarks)
{
RowMarkClause *rc = (RowMarkClause *) lfirst(l);
Oid relid = getrelid(rc->rti, rangeTable);
Oid relid;
Relation relation;
ExecRowMark *erm;
/* ignore "parent" rowmarks; they are irrelevant at runtime */
if (rc->isParent)
continue;
relid = getrelid(rc->rti, rangeTable);
relation = heap_open(relid, RowShareLock);
erm = (ExecRowMark *) palloc(sizeof(ExecRowMark));
erm->relation = relation;
erm->rti = rc->rti;
erm->prti = rc->prti;
erm->forUpdate = rc->forUpdate;
erm->noWait = rc->noWait;
/* We'll set up ctidAttno below */
/* We'll locate the junk attrs below */
erm->ctidAttNo = InvalidAttrNumber;
erm->toidAttNo = InvalidAttrNumber;
estate->es_rowMarks = lappend(estate->es_rowMarks, erm);
}
@ -822,17 +829,29 @@ InitPlan(QueryDesc *queryDesc, int eflags)
elog(ERROR, "could not find junk ctid column");
}
/* For SELECT FOR UPDATE/SHARE, find the ctid attrs now */
/* For SELECT FOR UPDATE/SHARE, find the junk attrs now */
foreach(l, estate->es_rowMarks)
{
ExecRowMark *erm = (ExecRowMark *) lfirst(l);
char resname[32];
snprintf(resname, sizeof(resname), "ctid%u", erm->rti);
/* always need the ctid */
snprintf(resname, sizeof(resname), "ctid%u",
erm->prti);
erm->ctidAttNo = ExecFindJunkAttribute(j, resname);
if (!AttributeNumberIsValid(erm->ctidAttNo))
elog(ERROR, "could not find junk \"%s\" column",
resname);
/* if child relation, need tableoid too */
if (erm->rti != erm->prti)
{
snprintf(resname, sizeof(resname), "tableoid%u",
erm->prti);
erm->toidAttNo = ExecFindJunkAttribute(j, resname);
if (!AttributeNumberIsValid(erm->toidAttNo))
elog(ERROR, "could not find junk \"%s\" column",
resname);
}
}
}
}
@ -1383,13 +1402,33 @@ lnext: ;
LockTupleMode lockmode;
HTSU_Result test;
/* if child rel, must check whether it produced this row */
if (erm->rti != erm->prti)
{
Oid tableoid;
datum = ExecGetJunkAttribute(slot,
erm->toidAttNo,
&isNull);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "tableoid is NULL");
tableoid = DatumGetObjectId(datum);
if (tableoid != RelationGetRelid(erm->relation))
{
/* this child is inactive right now */
continue;
}
}
/* okay, fetch the tuple by ctid */
datum = ExecGetJunkAttribute(slot,
erm->ctidAttNo,
&isNull);
/* shouldn't ever get a null result... */
if (isNull)
elog(ERROR, "ctid is NULL");
tuple.t_self = *((ItemPointer) DatumGetPointer(datum));
if (erm->forUpdate)
@ -2122,9 +2161,11 @@ EvalPlanQual(EState *estate, Index rti,
relation = NULL;
foreach(l, estate->es_rowMarks)
{
if (((ExecRowMark *) lfirst(l))->rti == rti)
ExecRowMark *erm = lfirst(l);
if (erm->rti == rti)
{
relation = ((ExecRowMark *) lfirst(l))->relation;
relation = erm->relation;
break;
}
}

4
src/backend/nodes/copyfuncs.c
View File

@ -15,7 +15,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.411 2008/11/11 18:13:32 tgl Exp $
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.412 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1735,8 +1735,10 @@ _copyRowMarkClause(RowMarkClause *from)
RowMarkClause *newnode = makeNode(RowMarkClause);
COPY_SCALAR_FIELD(rti);
COPY_SCALAR_FIELD(prti);
COPY_SCALAR_FIELD(forUpdate);
COPY_SCALAR_FIELD(noWait);
COPY_SCALAR_FIELD(isParent);
return newnode;
}

4
src/backend/nodes/equalfuncs.c
View File

@ -22,7 +22,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.336 2008/11/11 18:13:32 tgl Exp $
* $PostgreSQL: pgsql/src/backend/nodes/equalfuncs.c,v 1.337 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2005,8 +2005,10 @@ static bool
_equalRowMarkClause(RowMarkClause *a, RowMarkClause *b)
{
COMPARE_SCALAR_FIELD(rti);
COMPARE_SCALAR_FIELD(prti);
COMPARE_SCALAR_FIELD(forUpdate);
COMPARE_SCALAR_FIELD(noWait);
COMPARE_SCALAR_FIELD(isParent);
return true;
}

4
src/backend/nodes/outfuncs.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.344 2008/11/11 18:13:32 tgl Exp $
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.345 2008/11/15 19:43:46 tgl Exp $
*
* NOTES
* Every node type that can appear in stored rules' parsetrees *must*
@ -1900,8 +1900,10 @@ _outRowMarkClause(StringInfo str, RowMarkClause *node)
WRITE_NODE_TYPE("ROWMARKCLAUSE");
WRITE_UINT_FIELD(rti);
WRITE_UINT_FIELD(prti);
WRITE_BOOL_FIELD(forUpdate);
WRITE_BOOL_FIELD(noWait);
WRITE_BOOL_FIELD(isParent);
}
static void

4
src/backend/nodes/readfuncs.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.216 2008/10/06 17:39:26 tgl Exp $
* $PostgreSQL: pgsql/src/backend/nodes/readfuncs.c,v 1.217 2008/11/15 19:43:46 tgl Exp $
*
* NOTES
* Path and Plan nodes do not have any readfuncs support, because we
@ -226,8 +226,10 @@ _readRowMarkClause(void)
READ_LOCALS(RowMarkClause);
READ_UINT_FIELD(rti);
READ_UINT_FIELD(prti);
READ_BOOL_FIELD(forUpdate);
READ_BOOL_FIELD(noWait);
READ_BOOL_FIELD(isParent);
READ_DONE();
}

13
src/backend/optimizer/path/allpaths.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.176 2008/11/11 18:13:32 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.177 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -283,17 +283,6 @@ set_append_rel_pathlist(PlannerInfo *root, RelOptInfo *rel,
int nattrs;
ListCell *l;
/*
* XXX for now, can't handle inherited expansion of FOR UPDATE/SHARE; can
* we do better? (This will take some redesign because the executor
* currently supposes that every rowMark relation is involved in every row
* returned by the query.)
*/
if (get_rowmark(root->parse, parentRTindex))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("SELECT FOR UPDATE/SHARE is not supported for inheritance queries")));
/*
* Initialize to compute size estimates for whole append relation.
*

27
src/backend/optimizer/prep/preptlist.c
View File

@ -16,7 +16,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.93 2008/11/02 01:45:28 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.94 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -138,6 +138,11 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
char *resname;
TargetEntry *tle;
/* ignore child rels */
if (rc->rti != rc->prti)
continue;
/* always need the ctid */
var = makeVar(rc->rti,
SelfItemPointerAttributeNumber,
TIDOID,
@ -153,6 +158,26 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
true);
tlist = lappend(tlist, tle);
/* if parent of inheritance tree, need the tableoid too */
if (rc->isParent)
{
var = makeVar(rc->rti,
TableOidAttributeNumber,
OIDOID,
-1,
0);
resname = (char *) palloc(32);
snprintf(resname, 32, "tableoid%u", rc->rti);
tle = makeTargetEntry((Expr *) var,
list_length(tlist) + 1,
resname,
true);
tlist = lappend(tlist, tle);
}
}
}

39
src/backend/optimizer/prep/prepunion.c
View File

@ -22,7 +22,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.161 2008/11/11 18:13:32 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.162 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1169,6 +1169,7 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
{
Query *parse = root->parse;
Oid parentOID;
RowMarkClause *oldrc;
Relation oldrelation;
LOCKMODE lockmode;
List *inhOIDs;
@ -1208,6 +1209,15 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
return;
}
/*
* Find out if parent relation is selected FOR UPDATE/SHARE. If so,
* we need to mark its RowMarkClause as isParent = true, and generate
* a new RowMarkClause for each child.
*/
oldrc = get_rowmark(parse, rti);
if (oldrc)
oldrc->isParent = true;
/*
* Must open the parent relation to examine its tupdesc. We need not lock
* it since the rewriter already obtained at least AccessShareLock on each
@ -1221,14 +1231,15 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
* in the parse/rewrite/plan pipeline.
*
* If the parent relation is the query's result relation, then we need
* RowExclusiveLock. Otherwise, check to see if the relation is accessed
* FOR UPDATE/SHARE or not. We can't just grab AccessShareLock because
* then the executor would be trying to upgrade the lock, leading to
* possible deadlocks. (This code should match the parser and rewriter.)
* RowExclusiveLock. Otherwise, if it's accessed FOR UPDATE/SHARE, we
* need RowShareLock; otherwise AccessShareLock. We can't just grab
* AccessShareLock because then the executor would be trying to upgrade
* the lock, leading to possible deadlocks. (This code should match the
* parser and rewriter.)
*/
if (rti == parse->resultRelation)
lockmode = RowExclusiveLock;
else if (get_rowmark(parse, rti))
else if (oldrc)
lockmode = RowShareLock;
else
lockmode = AccessShareLock;
@ -1283,6 +1294,22 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
appinfo->parent_reloid = parentOID;
appinfos = lappend(appinfos, appinfo);
/*
* Build a RowMarkClause if parent is marked FOR UPDATE/SHARE.
*/
if (oldrc)
{
RowMarkClause *newrc = makeNode(RowMarkClause);
newrc->rti = childRTindex;
newrc->prti = rti;
newrc->forUpdate = oldrc->forUpdate;
newrc->noWait = oldrc->noWait;
newrc->isParent = false;
parse->rowMarks = lappend(parse->rowMarks, newrc);
}
/* Close child relations, but keep locks */
if (childOID != parentOID)
heap_close(newrelation, NoLock);

4
src/backend/parser/analyze.c
View File

@ -17,7 +17,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.382 2008/10/07 01:47:54 tgl Exp $
* $PostgreSQL: pgsql/src/backend/parser/analyze.c,v 1.383 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -2049,8 +2049,10 @@ applyLockingClause(Query *qry, Index rtindex, bool forUpdate, bool noWait)
/* Make a new RowMarkClause */
rc = makeNode(RowMarkClause);
rc->rti = rtindex;
rc->prti = rtindex;
rc->forUpdate = forUpdate;
rc->noWait = noWait;
rc->isParent = false;
qry->rowMarks = lappend(qry->rowMarks, rc);
}

5
src/backend/rewrite/rewriteManip.c
View File

@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.117 2008/10/22 20:17:52 tgl Exp $
* $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.118 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -352,6 +352,7 @@ OffsetVarNodes(Node *node, int offset, int sublevels_up)
RowMarkClause *rc = (RowMarkClause *) lfirst(l);
rc->rti += offset;
rc->prti += offset;
}
}
query_tree_walker(qry, OffsetVarNodes_walker,
@ -536,6 +537,8 @@ ChangeVarNodes(Node *node, int rt_index, int new_index, int sublevels_up)
if (rc->rti == rt_index)
rc->rti = new_index;
if (rc->prti == rt_index)
rc->prti = new_index;
}
}
query_tree_walker(qry, ChangeVarNodes_walker,

4
src/include/catalog/catversion.h
View File

@ -37,7 +37,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.507 2008/11/14 02:09:51 tgl Exp $
* $PostgreSQL: pgsql/src/include/catalog/catversion.h,v 1.508 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -53,6 +53,6 @@
*/
/* yyyymmddN */
#define CATALOG_VERSION_NO 200811133
#define CATALOG_VERSION_NO 200811151
#endif

9
src/include/nodes/execnodes.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.194 2008/10/31 19:37:56 tgl Exp $
* $PostgreSQL: pgsql/src/include/nodes/execnodes.h,v 1.195 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -368,14 +368,19 @@ typedef struct EState
} EState;
/* es_rowMarks is a list of these structs: */
/*
* es_rowMarks is a list of these structs. See RowMarkClause for details
* about rti and prti. toidAttno is not used in a "plain" rowmark.
*/
typedef struct ExecRowMark
{
Relation relation; /* opened and RowShareLock'd relation */
Index rti; /* its range table index */
Index prti; /* parent range table index, if child */
bool forUpdate; /* true = FOR UPDATE, false = FOR SHARE */
bool noWait; /* NOWAIT option */
AttrNumber ctidAttNo; /* resno of its ctid junk attribute */
AttrNumber toidAttNo; /* resno of tableoid junk attribute, if any */
} ExecRowMark;

13
src/include/nodes/parsenodes.h
View File

@ -13,7 +13,7 @@
* Portions Copyright (c) 1996-2008, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.377 2008/10/31 08:39:22 heikki Exp $
* $PostgreSQL: pgsql/src/include/nodes/parsenodes.h,v 1.378 2008/11/15 19:43:46 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -700,14 +700,23 @@ typedef struct SortGroupClause
* RowMarkClause -
* representation of FOR UPDATE/SHARE clauses
*
* We create a separate RowMarkClause node for each target relation
* We create a separate RowMarkClause node for each target relation. In the
* output of the parser and rewriter, all RowMarkClauses have rti == prti and
* isParent == false. When the planner discovers that a target relation
* is the root of an inheritance tree, it sets isParent true, and adds an
* additional RowMarkClause to the list for each child relation (including
* the target rel itself in its role as a child). The child entries have
* rti == child rel's RT index, prti == parent's RT index, and can therefore
* be recognized as children by the fact that prti != rti.
*/
typedef struct RowMarkClause
{
NodeTag type;
Index rti; /* range table index of target relation */
Index prti; /* range table index of parent relation */
bool forUpdate; /* true = FOR UPDATE, false = FOR SHARE */
bool noWait; /* NOWAIT option */
bool isParent; /* set by planner when expanding inheritance */
} RowMarkClause;
/*

2
src/test/regress/expected/portals.out
View File

@ -1118,7 +1118,7 @@ SELECT * FROM uctest;
(3 rows)
BEGIN;
DECLARE c1 CURSOR FOR SELECT * FROM uctest;
DECLARE c1 CURSOR FOR SELECT * FROM uctest FOR UPDATE;
FETCH 1 FROM c1;
f1 | f2
----+-------

2
src/test/regress/sql/portals.sql
View File

@ -393,7 +393,7 @@ INSERT INTO ucchild values(100, 'hundred');
SELECT * FROM uctest;
BEGIN;
DECLARE c1 CURSOR FOR SELECT * FROM uctest;
DECLARE c1 CURSOR FOR SELECT * FROM uctest FOR UPDATE;
FETCH 1 FROM c1;
UPDATE uctest SET f1 = f1 + 10 WHERE CURRENT OF c1;
FETCH 1 FROM c1;