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Commit46c508f

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Fix PARAM_EXEC assignment mechanism to be safe in the presence of WITH.
The planner previously assumed that parameter Vars having the same absolutequery level, varno, and varattno could safely be assigned the same runtimePARAM_EXEC slot, even though they might be different Vars appearing indifferent subqueries. This was (probably) safe before the introduction ofCTEs, but the lazy-evalution mechanism used for CTEs means that a CTE canbe executed during execution of some other subquery, causing the lifespanof Params at the same syntactic nesting level as the CTE to overlap withuse of the same slots inside the CTE. In 9.1 we created additional hazardsby using the same parameter-assignment technology for nestloop inner scanparameters, but it was broken before that, as illustrated by the addedregression test.To fix, restructure the planner's management of PlannerParamItems so thatitems having different semantic lifespans are kept rigorously separated.This will probably result in complex queries using more runtime PARAM_EXECslots than before, but the slots are cheap enough that this hardly matters.Also, stop generating PlannerParamItems containing Params for subqueryoutputs: all we really need to do is reserve the PARAM_EXEC slot number,and that now only takes incrementing a counter. The planning code issimpler and probably faster than before, as well as being more correct.Per report from Vik Reykja.These changes will mostly also need to be made in the back branches, butI'm going to hold off on that until after 9.2.0 wraps.
1 parente20a90e commit46c508f

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11 files changed

+269
-212
lines changed

11 files changed

+269
-212
lines changed

‎src/backend/nodes/outfuncs.c

Lines changed: 4 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -1666,14 +1666,14 @@ _outPlannerGlobal(StringInfo str, const PlannerGlobal *node)
16661666
WRITE_NODE_TYPE("PLANNERGLOBAL");
16671667

16681668
/* NB: this isn't a complete set of fields */
1669-
WRITE_NODE_FIELD(paramlist);
16701669
WRITE_NODE_FIELD(subplans);
16711670
WRITE_BITMAPSET_FIELD(rewindPlanIDs);
16721671
WRITE_NODE_FIELD(finalrtable);
16731672
WRITE_NODE_FIELD(finalrowmarks);
16741673
WRITE_NODE_FIELD(resultRelations);
16751674
WRITE_NODE_FIELD(relationOids);
16761675
WRITE_NODE_FIELD(invalItems);
1676+
WRITE_INT_FIELD(nParamExec);
16771677
WRITE_UINT_FIELD(lastPHId);
16781678
WRITE_UINT_FIELD(lastRowMarkId);
16791679
WRITE_BOOL_FIELD(transientPlan);
@@ -1688,6 +1688,7 @@ _outPlannerInfo(StringInfo str, const PlannerInfo *node)
16881688
WRITE_NODE_FIELD(parse);
16891689
WRITE_NODE_FIELD(glob);
16901690
WRITE_UINT_FIELD(query_level);
1691+
WRITE_NODE_FIELD(plan_params);
16911692
WRITE_BITMAPSET_FIELD(all_baserels);
16921693
WRITE_NODE_FIELD(join_rel_list);
16931694
WRITE_INT_FIELD(join_cur_level);
@@ -1754,6 +1755,7 @@ _outRelOptInfo(StringInfo str, const RelOptInfo *node)
17541755
WRITE_FLOAT_FIELD(allvisfrac,"%.6f");
17551756
WRITE_NODE_FIELD(subplan);
17561757
WRITE_NODE_FIELD(subroot);
1758+
WRITE_NODE_FIELD(subplan_params);
17571759
/* we don't try to print fdwroutine or fdw_private */
17581760
WRITE_NODE_FIELD(baserestrictinfo);
17591761
WRITE_NODE_FIELD(joininfo);
@@ -1950,7 +1952,7 @@ _outPlannerParamItem(StringInfo str, const PlannerParamItem *node)
19501952
WRITE_NODE_TYPE("PLANNERPARAMITEM");
19511953

19521954
WRITE_NODE_FIELD(item);
1953-
WRITE_UINT_FIELD(abslevel);
1955+
WRITE_INT_FIELD(paramId);
19541956
}
19551957

19561958
/*****************************************************************************

‎src/backend/optimizer/path/allpaths.c

Lines changed: 7 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -1145,13 +1145,20 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
11451145
else
11461146
tuple_fraction=root->tuple_fraction;
11471147

1148+
/* plan_params should not be in use in current query level */
1149+
Assert(root->plan_params==NIL);
1150+
11481151
/* Generate the plan for the subquery */
11491152
rel->subplan=subquery_planner(root->glob,subquery,
11501153
root,
11511154
false,tuple_fraction,
11521155
&subroot);
11531156
rel->subroot=subroot;
11541157

1158+
/* Isolate the params needed by this specific subplan */
1159+
rel->subplan_params=root->plan_params;
1160+
root->plan_params=NIL;
1161+
11551162
/*
11561163
* It's possible that constraint exclusion proved the subquery empty. If
11571164
* so, it's convenient to turn it back into a dummy path so that we will

‎src/backend/optimizer/plan/createplan.c

Lines changed: 32 additions & 31 deletions
Original file line numberDiff line numberDiff line change
@@ -84,7 +84,8 @@ static HashJoin *create_hashjoin_plan(PlannerInfo *root, HashPath *best_path,
8484
Plan*outer_plan,Plan*inner_plan);
8585
staticNode*replace_nestloop_params(PlannerInfo*root,Node*expr);
8686
staticNode*replace_nestloop_params_mutator(Node*node,PlannerInfo*root);
87-
staticvoididentify_nestloop_extparams(PlannerInfo*root,Plan*subplan);
87+
staticvoidprocess_subquery_nestloop_params(PlannerInfo*root,
88+
List*subplan_params);
8889
staticList*fix_indexqual_references(PlannerInfo*root,IndexPath*index_path);
8990
staticList*fix_indexorderby_references(PlannerInfo*root,IndexPath*index_path);
9091
staticNode*fix_indexqual_operand(Node*node,IndexOptInfo*index,intindexcol);
@@ -188,6 +189,9 @@ create_plan(PlannerInfo *root, Path *best_path)
188189
{
189190
Plan*plan;
190191

192+
/* plan_params should not be in use in current query level */
193+
Assert(root->plan_params==NIL);
194+
191195
/* Initialize this module's private workspace in PlannerInfo */
192196
root->curOuterRels=NULL;
193197
root->curOuterParams=NIL;
@@ -199,6 +203,12 @@ create_plan(PlannerInfo *root, Path *best_path)
199203
if (root->curOuterParams!=NIL)
200204
elog(ERROR,"failed to assign all NestLoopParams to plan nodes");
201205

206+
/*
207+
* Reset plan_params to ensure param IDs used for nestloop params are not
208+
* re-used later
209+
*/
210+
root->plan_params=NIL;
211+
202212
returnplan;
203213
}
204214

@@ -1662,7 +1672,8 @@ create_subqueryscan_plan(PlannerInfo *root, Path *best_path,
16621672
{
16631673
scan_clauses= (List*)
16641674
replace_nestloop_params(root, (Node*)scan_clauses);
1665-
identify_nestloop_extparams(root,best_path->parent->subplan);
1675+
process_subquery_nestloop_params(root,
1676+
best_path->parent->subplan_params);
16661677
}
16671678

16681679
scan_plan=make_subqueryscan(tlist,
@@ -2620,45 +2631,41 @@ replace_nestloop_params_mutator(Node *node, PlannerInfo *root)
26202631
}
26212632

26222633
/*
2623-
*identify_nestloop_extparams
2624-
*Identify extParams of a parameterized subquery that need to be fed
2634+
*process_subquery_nestloop_params
2635+
*Handle params of a parameterized subquery that need to be fed
26252636
* from an outer nestloop.
26262637
*
2638+
* Currently, that would be *all* params that a subquery in FROM has demanded
2639+
* from the current query level, since they must be LATERAL references.
2640+
*
26272641
* The subplan's references to the outer variables are already represented
26282642
* as PARAM_EXEC Params, so we need not modify the subplan here. What we
26292643
* do need to do is add entries to root->curOuterParams to signal the parent
26302644
* nestloop plan node that it must provide these values.
26312645
*/
26322646
staticvoid
2633-
identify_nestloop_extparams(PlannerInfo*root,Plan*subplan)
2647+
process_subquery_nestloop_params(PlannerInfo*root,List*subplan_params)
26342648
{
2635-
Bitmapset*tmpset;
2636-
intparamid;
2649+
ListCell*ppl;
26372650

2638-
/* Examine each extParam of the subquery's plan */
2639-
tmpset=bms_copy(subplan->extParam);
2640-
while ((paramid=bms_first_member(tmpset)) >=0)
2651+
foreach(ppl,subplan_params)
26412652
{
2642-
PlannerParamItem*pitem=list_nth(root->glob->paramlist,paramid);
2643-
2644-
/* Ignore anything coming from an upper query level */
2645-
if (pitem->abslevel!=root->query_level)
2646-
continue;
2653+
PlannerParamItem*pitem= (PlannerParamItem*)lfirst(ppl);
26472654

26482655
if (IsA(pitem->item,Var))
26492656
{
26502657
Var*var= (Var*)pitem->item;
26512658
NestLoopParam*nlp;
26522659
ListCell*lc;
26532660

2654-
/* If not from a nestloop outer rel,nothing to do */
2661+
/* If not from a nestloop outer rel,complain */
26552662
if (!bms_is_member(var->varno,root->curOuterRels))
2656-
continue;
2663+
elog(ERROR,"non-LATERAL parameter required by subquery");
26572664
/* Is this param already listed in root->curOuterParams? */
26582665
foreach(lc,root->curOuterParams)
26592666
{
26602667
nlp= (NestLoopParam*)lfirst(lc);
2661-
if (nlp->paramno==paramid)
2668+
if (nlp->paramno==pitem->paramId)
26622669
{
26632670
Assert(equal(var,nlp->paramval));
26642671
/* Present, so nothing to do */
@@ -2669,7 +2676,7 @@ identify_nestloop_extparams(PlannerInfo *root, Plan *subplan)
26692676
{
26702677
/* No, so add it */
26712678
nlp=makeNode(NestLoopParam);
2672-
nlp->paramno=paramid;
2679+
nlp->paramno=pitem->paramId;
26732680
nlp->paramval=copyObject(var);
26742681
root->curOuterParams=lappend(root->curOuterParams,nlp);
26752682
}
@@ -2680,22 +2687,15 @@ identify_nestloop_extparams(PlannerInfo *root, Plan *subplan)
26802687
NestLoopParam*nlp;
26812688
ListCell*lc;
26822689

2683-
/*
2684-
* If not from a nestloop outer rel, nothing to do. We use
2685-
* bms_overlap as a cheap/quick test to see if the PHV might be
2686-
* evaluated in the outer rels, and then grab its PlaceHolderInfo
2687-
* to tell for sure.
2688-
*/
2689-
if (!bms_overlap(phv->phrels,root->curOuterRels))
2690-
continue;
2690+
/* If not from a nestloop outer rel, complain */
26912691
if (!bms_is_subset(find_placeholder_info(root,phv, false)->ph_eval_at,
26922692
root->curOuterRels))
2693-
continue;
2693+
elog(ERROR,"non-LATERAL parameter required by subquery");
26942694
/* Is this param already listed in root->curOuterParams? */
26952695
foreach(lc,root->curOuterParams)
26962696
{
26972697
nlp= (NestLoopParam*)lfirst(lc);
2698-
if (nlp->paramno==paramid)
2698+
if (nlp->paramno==pitem->paramId)
26992699
{
27002700
Assert(equal(phv,nlp->paramval));
27012701
/* Present, so nothing to do */
@@ -2706,13 +2706,14 @@ identify_nestloop_extparams(PlannerInfo *root, Plan *subplan)
27062706
{
27072707
/* No, so add it */
27082708
nlp=makeNode(NestLoopParam);
2709-
nlp->paramno=paramid;
2709+
nlp->paramno=pitem->paramId;
27102710
nlp->paramval=copyObject(phv);
27112711
root->curOuterParams=lappend(root->curOuterParams,nlp);
27122712
}
27132713
}
2714+
else
2715+
elog(ERROR,"unexpected type of subquery parameter");
27142716
}
2715-
bms_free(tmpset);
27162717
}
27172718

27182719
/*

‎src/backend/optimizer/plan/planner.c

Lines changed: 4 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -155,7 +155,6 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
155155
glob=makeNode(PlannerGlobal);
156156

157157
glob->boundParams=boundParams;
158-
glob->paramlist=NIL;
159158
glob->subplans=NIL;
160159
glob->subroots=NIL;
161160
glob->rewindPlanIDs=NULL;
@@ -164,6 +163,7 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
164163
glob->resultRelations=NIL;
165164
glob->relationOids=NIL;
166165
glob->invalItems=NIL;
166+
glob->nParamExec=0;
167167
glob->lastPHId=0;
168168
glob->lastRowMarkId=0;
169169
glob->transientPlan= false;
@@ -243,7 +243,7 @@ standard_planner(Query *parse, int cursorOptions, ParamListInfo boundParams)
243243
result->rowMarks=glob->finalrowmarks;
244244
result->relationOids=glob->relationOids;
245245
result->invalItems=glob->invalItems;
246-
result->nParamExec=list_length(glob->paramlist);
246+
result->nParamExec=glob->nParamExec;
247247

248248
returnresult;
249249
}
@@ -295,6 +295,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
295295
root->glob=glob;
296296
root->query_level=parent_root ?parent_root->query_level+1 :1;
297297
root->parent_root=parent_root;
298+
root->plan_params=NIL;
298299
root->planner_cxt=CurrentMemoryContext;
299300
root->init_plans=NIL;
300301
root->cte_plan_ids=NIL;
@@ -586,7 +587,7 @@ subquery_planner(PlannerGlobal *glob, Query *parse,
586587
* and attach the initPlans to the top plan node.
587588
*/
588589
if (list_length(glob->subplans)!=num_old_subplans||
589-
root->glob->paramlist!=NIL)
590+
root->glob->nParamExec>0)
590591
SS_finalize_plan(root,plan, true);
591592

592593
/* Return internal info if caller wants it */

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