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Fix PlanRowMark/ExecRowMark structures to handle inheritance correctly.

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In an inherited UPDATE/DELETE, each target table has its own subplan,
because it might have a column set different from other targets.  This
means that the resjunk columns we add to support EvalPlanQual might be
at different physical column numbers in each subplan.  The EvalPlanQual
rewrite I did for 9.0 failed to account for this, resulting in possible
misbehavior or even crashes during concurrent updates to the same row,
as seen in a recent report from Gordon Shannon.  Revise the data structure
so that we track resjunk column numbers separately for each subplan.

I also chose to move responsibility for identifying the physical column
numbers back to executor startup, instead of assuming that numbers derived
during preprocess_targetlist would stay valid throughout subsequent
massaging of the plan.  That's a bit slower, so we might want to consider
undoing it someday; but it would complicate the patch considerably and
didn't seem justifiable in a bug fix that has to be back-patched to 9.0.
This commit is contained in:
Tom Lane
2011-01-12 20:47:02 -05:00
parent 7a32ff9732
commit d487afbb81
12 changed files with 193 additions and 123 deletions
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8
src/backend/optimizer/plan/planner.c
View File

@ -1929,10 +1929,6 @@ preprocess_rowmarks(PlannerInfo *root)
newrc->markType = ROW_MARK_SHARE;
newrc->noWait = rc->noWait;
newrc->isParent = false;
/* attnos will be assigned in preprocess_targetlist */
newrc->ctidAttNo = InvalidAttrNumber;
newrc->toidAttNo = InvalidAttrNumber;
newrc->wholeAttNo = InvalidAttrNumber;
prowmarks = lappend(prowmarks, newrc);
}
@ -1959,10 +1955,6 @@ preprocess_rowmarks(PlannerInfo *root)
newrc->markType = ROW_MARK_COPY;
newrc->noWait = false; /* doesn't matter */
newrc->isParent = false;
/* attnos will be assigned in preprocess_targetlist */
newrc->ctidAttNo = InvalidAttrNumber;
newrc->toidAttNo = InvalidAttrNumber;
newrc->wholeAttNo = InvalidAttrNumber;
prowmarks = lappend(prowmarks, newrc);
}

17
src/backend/optimizer/prep/preptlist.c
View File

@ -80,8 +80,7 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
/*
* Add necessary junk columns for rowmarked rels. These values are needed
* for locking of rels selected FOR UPDATE/SHARE, and to do EvalPlanQual
* rechecking. While we are at it, store these junk attnos in the
* PlanRowMark list so that we don't have to redetermine them at runtime.
* rechecking. See comments for PlanRowMark in plannodes.h.
*/
foreach(lc, root->rowMarks)
{
@ -90,18 +89,9 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
char resname[32];
TargetEntry *tle;
/* child rels should just use the same junk attrs as their parents */
/* child rels use the same junk attrs as their parents */
if (rc->rti != rc->prti)
{
PlanRowMark *prc = get_plan_rowmark(root->rowMarks, rc->prti);
/* parent should have appeared earlier in list */
if (prc == NULL || prc->toidAttNo == InvalidAttrNumber)
elog(ERROR, "parent PlanRowMark not processed yet");
rc->ctidAttNo = prc->ctidAttNo;
rc->toidAttNo = prc->toidAttNo;
continue;
}
if (rc->markType != ROW_MARK_COPY)
{
@ -117,7 +107,6 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
pstrdup(resname),
true);
tlist = lappend(tlist, tle);
rc->ctidAttNo = tle->resno;
/* if parent of inheritance tree, need the tableoid too */
if (rc->isParent)
@ -133,7 +122,6 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
pstrdup(resname),
true);
tlist = lappend(tlist, tle);
rc->toidAttNo = tle->resno;
}
}
else
@ -148,7 +136,6 @@ preprocess_targetlist(PlannerInfo *root, List *tlist)
pstrdup(resname),
true);
tlist = lappend(tlist, tle);
rc->wholeAttNo = tle->resno;
}
}

4
src/backend/optimizer/prep/prepunion.c
View File

@ -1292,10 +1292,6 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
newrc->markType = oldrc->markType;
newrc->noWait = oldrc->noWait;
newrc->isParent = false;
/* junk attrs for children are not identified yet */
newrc->ctidAttNo = InvalidAttrNumber;
newrc->toidAttNo = InvalidAttrNumber;
newrc->wholeAttNo = InvalidAttrNumber;
root->rowMarks = lappend(root->rowMarks, newrc);
}