From e617f0d7e4084f85104361568ef5f865ebfa0005 Mon Sep 17 00:00:00 2001
From: Tom Lane <tgl@sss.pgh.pa.us>
Date: Wed, 9 Feb 2011 23:27:07 -0500
Subject: [PATCH] Fix improper matching of resjunk column names for FOR UPDATE
in subselect.
Flattening of subquery range tables during setrefs.c could lead to the
rangetable indexes in PlanRowMark nodes not matching up with the column
names previously assigned to the corresponding resjunk ctid (resp. tableoid
or wholerow) columns. Typical symptom would be either a "cannot extract
system attribute from virtual tuple" error or an Assert failure. This
wasn't a problem before 9.0 because we didn't support FOR UPDATE below the
top query level, and so the final flattening could never renumber an RTE
that was relevant to FOR UPDATE. Fix by using a plan-tree-wide unique
number for each PlanRowMark to label the associated resjunk columns, so
that the number need not change during flattening.
Per report from David Johnston (though I'm darned if I can see how this got
past initial testing of the relevant code). Back-patch to 9.0.
---
src/backend/executor/execMain.c | 13 ++++++++++---
src/backend/nodes/copyfuncs.c | 1 +
src/backend/nodes/outfuncs.c | 2 ++
src/backend/optimizer/plan/planner.c | 3 +++
src/backend/optimizer/plan/setrefs.c | 2 +-
src/backend/optimizer/prep/preptlist.c | 6 +++---
src/backend/optimizer/prep/prepunion.c | 1 +
src/include/nodes/execnodes.h | 1 +
src/include/nodes/plannodes.h | 7 ++++++-
src/include/nodes/relation.h | 2 ++
10 files changed, 30 insertions(+), 8 deletions(-)
diff --git a/src/backend/executor/execMain.c b/src/backend/executor/execMain.c
index 600f7e03345..7df7f5cdf0d 100644
--- a/src/backend/executor/execMain.c
+++ b/src/backend/executor/execMain.c
@@ -742,6 +742,7 @@ InitPlan(QueryDesc *queryDesc, int eflags)
erm->relation = relation;
erm->rti = rc->rti;
erm->prti = rc->prti;
+ erm->rowmarkId = rc->rowmarkId;
erm->markType = rc->markType;
erm->noWait = rc->noWait;
ItemPointerSetInvalid(&(erm->curCtid));
@@ -1425,23 +1426,29 @@ ExecBuildAuxRowMark(ExecRowMark *erm, List *targetlist)
/* if child rel, need tableoid */
if (erm->rti != erm->prti)
{
- snprintf(resname, sizeof(resname), "tableoid%u", erm->prti);
+ snprintf(resname, sizeof(resname), "tableoid%u", erm->rowmarkId);
aerm->toidAttNo = ExecFindJunkAttributeInTlist(targetlist,
resname);
+ if (!AttributeNumberIsValid(aerm->toidAttNo))
+ elog(ERROR, "could not find junk %s column", resname);
}
/* always need ctid for real relations */
- snprintf(resname, sizeof(resname), "ctid%u", erm->prti);
+ snprintf(resname, sizeof(resname), "ctid%u", erm->rowmarkId);
aerm->ctidAttNo = ExecFindJunkAttributeInTlist(targetlist,
resname);
+ if (!AttributeNumberIsValid(aerm->ctidAttNo))
+ elog(ERROR, "could not find junk %s column", resname);
}
else
{
Assert(erm->markType == ROW_MARK_COPY);
- snprintf(resname, sizeof(resname), "wholerow%u", erm->prti);
+ snprintf(resname, sizeof(resname), "wholerow%u", erm->rowmarkId);
aerm->wholeAttNo = ExecFindJunkAttributeInTlist(targetlist,
resname);
+ if (!AttributeNumberIsValid(aerm->wholeAttNo))
+ elog(ERROR, "could not find junk %s column", resname);
}
return aerm;
diff --git a/src/backend/nodes/copyfuncs.c b/src/backend/nodes/copyfuncs.c
index 3d898326d7a..83630924f63 100644
--- a/src/backend/nodes/copyfuncs.c
+++ b/src/backend/nodes/copyfuncs.c
@@ -906,6 +906,7 @@ _copyPlanRowMark(PlanRowMark *from)
COPY_SCALAR_FIELD(rti);
COPY_SCALAR_FIELD(prti);
+ COPY_SCALAR_FIELD(rowmarkId);
COPY_SCALAR_FIELD(markType);
COPY_SCALAR_FIELD(noWait);
COPY_SCALAR_FIELD(isParent);
diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index 3b3e5448fd5..5c943bc2543 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -808,6 +808,7 @@ _outPlanRowMark(StringInfo str, PlanRowMark *node)
WRITE_UINT_FIELD(rti);
WRITE_UINT_FIELD(prti);
+ WRITE_UINT_FIELD(rowmarkId);
WRITE_ENUM_FIELD(markType, RowMarkType);
WRITE_BOOL_FIELD(noWait);
WRITE_BOOL_FIELD(isParent);
@@ -1609,6 +1610,7 @@ _outPlannerGlobal(StringInfo str, PlannerGlobal *node)
WRITE_NODE_FIELD(relationOids);
WRITE_NODE_FIELD(invalItems);
WRITE_UINT_FIELD(lastPHId);
+ WRITE_UINT_FIELD(lastRowMarkId);
WRITE_BOOL_FIELD(transientPlan);
}
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index b52eebe2aac..01b90383cf3 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -166,6 +166,7 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
glob->relationOids = NIL;
glob->invalItems = NIL;
glob->lastPHId = 0;
+ glob->lastRowMarkId = 0;
glob->transientPlan = false;
/* Determine what fraction of the plan is likely to be scanned */
@@ -1885,6 +1886,7 @@ preprocess_rowmarks(PlannerInfo *root)
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = rc->rti;
+ newrc->rowmarkId = ++(root->glob->lastRowMarkId);
if (rc->forUpdate)
newrc->markType = ROW_MARK_EXCLUSIVE;
else
@@ -1910,6 +1912,7 @@ preprocess_rowmarks(PlannerInfo *root)
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = i;
+ newrc->rowmarkId = ++(root->glob->lastRowMarkId);
/* real tables support REFERENCE, anything else needs COPY */
if (rte->rtekind == RTE_RELATION)
newrc->markType = ROW_MARK_REFERENCE;
diff --git a/src/backend/optimizer/plan/setrefs.c b/src/backend/optimizer/plan/setrefs.c
index 867238ecc8b..d004f6cf12f 100644
--- a/src/backend/optimizer/plan/setrefs.c
+++ b/src/backend/optimizer/plan/setrefs.c
@@ -252,7 +252,7 @@ set_plan_references(PlannerGlobal *glob, Plan *plan,
newrc = (PlanRowMark *) palloc(sizeof(PlanRowMark));
memcpy(newrc, rc, sizeof(PlanRowMark));
- /* adjust indexes */
+ /* adjust indexes ... but *not* the rowmarkId */
newrc->rti += rtoffset;
newrc->prti += rtoffset;
diff --git a/src/backend/optimizer/prep/preptlist.c b/src/backend/optimizer/prep/preptlist.c
index 34b38eb3298..63447aa536e 100644
--- a/src/backend/optimizer/prep/preptlist.c
+++ b/src/backend/optimizer/prep/preptlist.c
@@ -102,7 +102,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
-1,
InvalidOid,
0);
- snprintf(resname, sizeof(resname), "ctid%u", rc->rti);
+ snprintf(resname, sizeof(resname), "ctid%u", rc->rowmarkId);
tle = makeTargetEntry((Expr *) var,
list_length(tlist) + 1,
pstrdup(resname),
@@ -118,7 +118,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
-1,
InvalidOid,
0);
- snprintf(resname, sizeof(resname), "tableoid%u", rc->rti);
+ snprintf(resname, sizeof(resname), "tableoid%u", rc->rowmarkId);
tle = makeTargetEntry((Expr *) var,
list_length(tlist) + 1,
pstrdup(resname),
@@ -132,7 +132,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
var = makeWholeRowVar(rt_fetch(rc->rti, range_table),
rc->rti,
0);
- snprintf(resname, sizeof(resname), "wholerow%u", rc->rti);
+ snprintf(resname, sizeof(resname), "wholerow%u", rc->rowmarkId);
tle = makeTargetEntry((Expr *) var,
list_length(tlist) + 1,
pstrdup(resname),
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c
index f62af6c37da..606e5fe60a5 100644
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -1294,6 +1294,7 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
newrc->rti = childRTindex;
newrc->prti = rti;
+ newrc->rowmarkId = oldrc->rowmarkId;
newrc->markType = oldrc->markType;
newrc->noWait = oldrc->noWait;
newrc->isParent = false;
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index 546b581b6d8..44da70ff608 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -417,6 +417,7 @@ typedef struct ExecRowMark
Relation relation; /* opened and suitably locked relation */
Index rti; /* its range table index */
Index prti; /* parent range table index, if child */
+ Index rowmarkId; /* unique identifier for resjunk columns */
RowMarkType markType; /* see enum in nodes/plannodes.h */
bool noWait; /* NOWAIT option */
ItemPointerData curCtid; /* ctid of currently locked tuple, if any */
diff --git a/src/include/nodes/plannodes.h b/src/include/nodes/plannodes.h
index 6ba2f6005a2..b4fb4f211b5 100644
--- a/src/include/nodes/plannodes.h
+++ b/src/include/nodes/plannodes.h
@@ -749,7 +749,11 @@ typedef enum RowMarkType
* The tableoid column is only present for an inheritance hierarchy.
* When markType == ROW_MARK_COPY, there is instead a single column named
* wholerow%u whole-row value of relation
- * In all three cases, %u represents the parent rangetable index (prti).
+ * In all three cases, %u represents the rowmark ID number (rowmarkId).
+ * This number is unique within a plan tree, except that child relation
+ * entries copy their parent's rowmarkId. (Assigning unique numbers
+ * means we needn't renumber rowmarkIds when flattening subqueries, which
+ * would require finding and renaming the resjunk columns as well.)
* Note this means that all tables in an inheritance hierarchy share the
* same resjunk column names. However, in an inherited UPDATE/DELETE the
* columns could have different physical column numbers in each subplan.
@@ -759,6 +763,7 @@ typedef struct PlanRowMark
NodeTag type;
Index rti; /* range table index of markable relation */
Index prti; /* range table index of parent relation */
+ Index rowmarkId; /* unique identifier for resjunk columns */
RowMarkType markType; /* see enum above */
bool noWait; /* NOWAIT option */
bool isParent; /* true if this is a "dummy" parent entry */
diff --git a/src/include/nodes/relation.h b/src/include/nodes/relation.h
index b3ca5b5e329..49ce441e624 100644
--- a/src/include/nodes/relation.h
+++ b/src/include/nodes/relation.h
@@ -82,6 +82,8 @@ typedef struct PlannerGlobal
Index lastPHId; /* highest PlaceHolderVar ID assigned */
+ Index lastRowMarkId; /* highest PlanRowMark ID assigned */
+
bool transientPlan; /* redo plan when TransactionXmin changes? */
} PlannerGlobal;
--
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