1
/*-------------------------------------------------------------------------
4
* Planning routines for subselects and parameters.
6
* Portions Copyright (c) 1996-2009, PostgreSQL Global Development Group
7
* Portions Copyright (c) 1994, Regents of the University of California
12
*-------------------------------------------------------------------------
16
#include "catalog/pg_operator.h"
17
#include "catalog/pg_type.h"
18
#include "miscadmin.h"
19
#include "nodes/makefuncs.h"
20
#include "nodes/nodeFuncs.h"
21
#include "optimizer/clauses.h"
22
#include "optimizer/cost.h"
23
#include "optimizer/planmain.h"
24
#include "optimizer/planner.h"
25
#include "optimizer/prep.h"
26
#include "optimizer/subselect.h"
27
#include "optimizer/var.h"
28
#include "parser/parse_relation.h"
29
#include "parser/parsetree.h"
30
#include "rewrite/rewriteManip.h"
31
#include "utils/builtins.h"
32
#include "utils/lsyscache.h"
33
#include "utils/syscache.h"
36
typedef struct convert_testexpr_context
39
List *subst_nodes; /* Nodes to substitute for Params */
40
} convert_testexpr_context;
42
typedef struct process_sublinks_context
46
} process_sublinks_context;
48
typedef struct finalize_primnode_context
51
Bitmapset *paramids; /* Non-local PARAM_EXEC paramids found */
52
} finalize_primnode_context;
55
static Node *build_subplan(PlannerInfo *root, Plan *plan, List *rtable,
56
SubLinkType subLinkType, Node *testexpr,
57
bool adjust_testexpr, bool unknownEqFalse);
58
static List *generate_subquery_params(PlannerInfo *root, List *tlist,
60
static List *generate_subquery_vars(PlannerInfo *root, List *tlist,
62
static Node *convert_testexpr(PlannerInfo *root,
65
static Node *convert_testexpr_mutator(Node *node,
66
convert_testexpr_context *context);
67
static bool subplan_is_hashable(Plan *plan);
68
static bool testexpr_is_hashable(Node *testexpr);
69
static bool hash_ok_operator(OpExpr *expr);
70
static bool simplify_EXISTS_query(Query *query);
71
static Query *convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
72
Node **testexpr, List **paramIds);
73
static Node *replace_correlation_vars_mutator(Node *node, PlannerInfo *root);
74
static Node *process_sublinks_mutator(Node *node,
75
process_sublinks_context *context);
76
static Bitmapset *finalize_plan(PlannerInfo *root,
78
Bitmapset *valid_params);
79
static bool finalize_primnode(Node *node, finalize_primnode_context *context);
83
* Generate a Param node to replace the given Var,
84
* which is expected to have varlevelsup > 0 (ie, it is not local).
87
replace_outer_var(PlannerInfo *root, Var *var)
91
PlannerParamItem *pitem;
95
Assert(var->varlevelsup > 0 && var->varlevelsup < root->query_level);
96
abslevel = root->query_level - var->varlevelsup;
99
* If there's already a paramlist entry for this same Var, just use it.
100
* NOTE: in sufficiently complex querytrees, it is possible for the same
101
* varno/abslevel to refer to different RTEs in different parts of the
102
* parsetree, so that different fields might end up sharing the same Param
103
* number. As long as we check the vartype/typmod as well, I believe that
104
* this sort of aliasing will cause no trouble. The correct field should
105
* get stored into the Param slot at execution in each part of the tree.
108
foreach(ppl, root->glob->paramlist)
110
pitem = (PlannerParamItem *) lfirst(ppl);
111
if (pitem->abslevel == abslevel && IsA(pitem->item, Var))
113
Var *pvar = (Var *) pitem->item;
115
if (pvar->varno == var->varno &&
116
pvar->varattno == var->varattno &&
117
pvar->vartype == var->vartype &&
118
pvar->vartypmod == var->vartypmod)
126
/* Nope, so make a new one */
127
var = (Var *) copyObject(var);
128
var->varlevelsup = 0;
130
pitem = makeNode(PlannerParamItem);
131
pitem->item = (Node *) var;
132
pitem->abslevel = abslevel;
134
root->glob->paramlist = lappend(root->glob->paramlist, pitem);
135
/* i is already the correct index for the new item */
138
retval = makeNode(Param);
139
retval->paramkind = PARAM_EXEC;
141
retval->paramtype = var->vartype;
142
retval->paramtypmod = var->vartypmod;
143
retval->location = -1;
149
* Generate a Param node to replace the given Aggref
150
* which is expected to have agglevelsup > 0 (ie, it is not local).
153
replace_outer_agg(PlannerInfo *root, Aggref *agg)
156
PlannerParamItem *pitem;
160
Assert(agg->agglevelsup > 0 && agg->agglevelsup < root->query_level);
161
abslevel = root->query_level - agg->agglevelsup;
164
* It does not seem worthwhile to try to match duplicate outer aggs. Just
165
* make a new slot every time.
167
agg = (Aggref *) copyObject(agg);
168
IncrementVarSublevelsUp((Node *) agg, -((int) agg->agglevelsup), 0);
169
Assert(agg->agglevelsup == 0);
171
pitem = makeNode(PlannerParamItem);
172
pitem->item = (Node *) agg;
173
pitem->abslevel = abslevel;
175
root->glob->paramlist = lappend(root->glob->paramlist, pitem);
176
i = list_length(root->glob->paramlist) - 1;
178
retval = makeNode(Param);
179
retval->paramkind = PARAM_EXEC;
181
retval->paramtype = agg->aggtype;
182
retval->paramtypmod = -1;
183
retval->location = -1;
189
* Generate a new Param node that will not conflict with any other.
191
* This is used to allocate PARAM_EXEC slots for subplan outputs.
194
generate_new_param(PlannerInfo *root, Oid paramtype, int32 paramtypmod)
197
PlannerParamItem *pitem;
199
retval = makeNode(Param);
200
retval->paramkind = PARAM_EXEC;
201
retval->paramid = list_length(root->glob->paramlist);
202
retval->paramtype = paramtype;
203
retval->paramtypmod = paramtypmod;
204
retval->location = -1;
206
pitem = makeNode(PlannerParamItem);
207
pitem->item = (Node *) retval;
208
pitem->abslevel = root->query_level;
210
root->glob->paramlist = lappend(root->glob->paramlist, pitem);
216
* Assign a (nonnegative) PARAM_EXEC ID for a recursive query's worktable.
219
SS_assign_worktable_param(PlannerInfo *root)
223
/* We generate a Param of datatype INTERNAL */
224
param = generate_new_param(root, INTERNALOID, -1);
225
/* ... but the caller only cares about its ID */
226
return param->paramid;
230
* Get the datatype of the first column of the plan's output.
232
* This is stored for ARRAY_SUBLINK execution and for exprType()/exprTypmod(),
233
* which have no way to get at the plan associated with a SubPlan node.
234
* We really only need the info for EXPR_SUBLINK and ARRAY_SUBLINK subplans,
235
* but for consistency we save it always.
238
get_first_col_type(Plan *plan, Oid *coltype, int32 *coltypmod)
240
/* In cases such as EXISTS, tlist might be empty; arbitrarily use VOID */
241
if (plan->targetlist)
243
TargetEntry *tent = (TargetEntry *) linitial(plan->targetlist);
245
Assert(IsA(tent, TargetEntry));
248
*coltype = exprType((Node *) tent->expr);
249
*coltypmod = exprTypmod((Node *) tent->expr);
258
* Convert a SubLink (as created by the parser) into a SubPlan.
260
* We are given the SubLink's contained query, type, and testexpr. We are
261
* also told if this expression appears at top level of a WHERE/HAVING qual.
263
* Note: we assume that the testexpr has been AND/OR flattened (actually,
264
* it's been through eval_const_expressions), but not converted to
265
* implicit-AND form; and any SubLinks in it should already have been
266
* converted to SubPlans. The subquery is as yet untouched, however.
268
* The result is whatever we need to substitute in place of the SubLink
269
* node in the executable expression. This will be either the SubPlan
270
* node (if we have to do the subplan as a subplan), or a Param node
271
* representing the result of an InitPlan, or a row comparison expression
272
* tree containing InitPlan Param nodes.
275
make_subplan(PlannerInfo *root, Query *orig_subquery, SubLinkType subLinkType,
276
Node *testexpr, bool isTopQual)
279
bool simple_exists = false;
280
double tuple_fraction;
282
PlannerInfo *subroot;
286
* Copy the source Query node. This is a quick and dirty kluge to resolve
287
* the fact that the parser can generate trees with multiple links to the
288
* same sub-Query node, but the planner wants to scribble on the Query.
289
* Try to clean this up when we do querytree redesign...
291
subquery = (Query *) copyObject(orig_subquery);
294
* If it's an EXISTS subplan, we might be able to simplify it.
296
if (subLinkType == EXISTS_SUBLINK)
297
simple_exists = simplify_EXISTS_query(subquery);
300
* For an EXISTS subplan, tell lower-level planner to expect that only the
301
* first tuple will be retrieved. For ALL and ANY subplans, we will be
302
* able to stop evaluating if the test condition fails or matches, so very
303
* often not all the tuples will be retrieved; for lack of a better idea,
304
* specify 50% retrieval. For EXPR and ROWCOMPARE subplans, use default
305
* behavior (we're only expecting one row out, anyway).
307
* NOTE: if you change these numbers, also change cost_subplan() in
310
* XXX If an ANY subplan is uncorrelated, build_subplan may decide to hash
311
* its output. In that case it would've been better to specify full
312
* retrieval. At present, however, we can only check hashability after
313
* we've made the subplan :-(. (Determining whether it'll fit in work_mem
314
* is the really hard part.) Therefore, we don't want to be too
315
* optimistic about the percentage of tuples retrieved, for fear of
316
* selecting a plan that's bad for the materialization case.
318
if (subLinkType == EXISTS_SUBLINK)
319
tuple_fraction = 1.0; /* just like a LIMIT 1 */
320
else if (subLinkType == ALL_SUBLINK ||
321
subLinkType == ANY_SUBLINK)
322
tuple_fraction = 0.5; /* 50% */
324
tuple_fraction = 0.0; /* default behavior */
327
* Generate the plan for the subquery.
329
plan = subquery_planner(root->glob, subquery,
331
false, tuple_fraction,
334
/* And convert to SubPlan or InitPlan format. */
335
result = build_subplan(root, plan, subroot->parse->rtable,
336
subLinkType, testexpr, true, isTopQual);
339
* If it's a correlated EXISTS with an unimportant targetlist, we might be
340
* able to transform it to the equivalent of an IN and then implement it
341
* by hashing. We don't have enough information yet to tell which way
342
* is likely to be better (it depends on the expected number of executions
343
* of the EXISTS qual, and we are much too early in planning the outer
344
* query to be able to guess that). So we generate both plans, if
345
* possible, and leave it to the executor to decide which to use.
347
if (simple_exists && IsA(result, SubPlan))
352
/* Make a second copy of the original subquery */
353
subquery = (Query *) copyObject(orig_subquery);
354
/* and re-simplify */
355
simple_exists = simplify_EXISTS_query(subquery);
356
Assert(simple_exists);
357
/* See if it can be converted to an ANY query */
358
subquery = convert_EXISTS_to_ANY(root, subquery,
359
&newtestexpr, ¶mIds);
362
/* Generate the plan for the ANY subquery; we'll need all rows */
363
plan = subquery_planner(root->glob, subquery,
368
/* Now we can check if it'll fit in work_mem */
369
if (subplan_is_hashable(plan))
372
AlternativeSubPlan *asplan;
374
/* OK, convert to SubPlan format. */
375
hashplan = (SubPlan *) build_subplan(root, plan,
376
subroot->parse->rtable,
377
ANY_SUBLINK, newtestexpr,
379
/* Check we got what we expected */
380
Assert(IsA(hashplan, SubPlan));
381
Assert(hashplan->parParam == NIL);
382
Assert(hashplan->useHashTable);
383
/* build_subplan won't have filled in paramIds */
384
hashplan->paramIds = paramIds;
386
/* Leave it to the executor to decide which plan to use */
387
asplan = makeNode(AlternativeSubPlan);
388
asplan->subplans = list_make2(result, hashplan);
389
result = (Node *) asplan;
398
* Build a SubPlan node given the raw inputs --- subroutine for make_subplan
400
* Returns either the SubPlan, or an expression using initplan output Params,
401
* as explained in the comments for make_subplan.
404
build_subplan(PlannerInfo *root, Plan *plan, List *rtable,
405
SubLinkType subLinkType, Node *testexpr,
406
bool adjust_testexpr, bool unknownEqFalse)
415
* Initialize the SubPlan node. Note plan_id isn't set till further down,
416
* likewise the cost fields.
418
splan = makeNode(SubPlan);
419
splan->subLinkType = subLinkType;
420
splan->testexpr = NULL;
421
splan->paramIds = NIL;
422
get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod);
423
splan->useHashTable = false;
424
splan->unknownEqFalse = unknownEqFalse;
425
splan->setParam = NIL;
426
splan->parParam = NIL;
430
* Make parParam and args lists of param IDs and expressions that current
431
* query level will pass to this child plan.
433
tmpset = bms_copy(plan->extParam);
434
while ((paramid = bms_first_member(tmpset)) >= 0)
436
PlannerParamItem *pitem = list_nth(root->glob->paramlist, paramid);
438
if (pitem->abslevel == root->query_level)
440
splan->parParam = lappend_int(splan->parParam, paramid);
442
* The Var or Aggref has already been adjusted to have the correct
443
* varlevelsup or agglevelsup. We probably don't even need to
444
* copy it again, but be safe.
446
splan->args = lappend(splan->args, copyObject(pitem->item));
452
* Un-correlated or undirect correlated plans of EXISTS, EXPR, ARRAY, or
453
* ROWCOMPARE types can be used as initPlans. For EXISTS, EXPR, or ARRAY,
454
* we just produce a Param referring to the result of evaluating the
455
* initPlan. For ROWCOMPARE, we must modify the testexpr tree to contain
456
* PARAM_EXEC Params instead of the PARAM_SUBLINK Params emitted by the
459
if (splan->parParam == NIL && subLinkType == EXISTS_SUBLINK)
463
Assert(testexpr == NULL);
464
prm = generate_new_param(root, BOOLOID, -1);
465
splan->setParam = list_make1_int(prm->paramid);
467
result = (Node *) prm;
469
else if (splan->parParam == NIL && subLinkType == EXPR_SUBLINK)
471
TargetEntry *te = linitial(plan->targetlist);
474
Assert(!te->resjunk);
475
Assert(testexpr == NULL);
476
prm = generate_new_param(root,
477
exprType((Node *) te->expr),
478
exprTypmod((Node *) te->expr));
479
splan->setParam = list_make1_int(prm->paramid);
481
result = (Node *) prm;
483
else if (splan->parParam == NIL && subLinkType == ARRAY_SUBLINK)
485
TargetEntry *te = linitial(plan->targetlist);
489
Assert(!te->resjunk);
490
Assert(testexpr == NULL);
491
arraytype = get_array_type(exprType((Node *) te->expr));
492
if (!OidIsValid(arraytype))
493
elog(ERROR, "could not find array type for datatype %s",
494
format_type_be(exprType((Node *) te->expr)));
495
prm = generate_new_param(root,
497
exprTypmod((Node *) te->expr));
498
splan->setParam = list_make1_int(prm->paramid);
500
result = (Node *) prm;
502
else if (splan->parParam == NIL && subLinkType == ROWCOMPARE_SUBLINK)
504
/* Adjust the Params */
507
Assert(testexpr != NULL);
508
params = generate_subquery_params(root,
511
result = convert_testexpr(root,
514
splan->setParam = list_copy(splan->paramIds);
518
* The executable expression is returned to become part of the outer
519
* plan's expression tree; it is not kept in the initplan node.
525
* Adjust the Params in the testexpr, unless caller said it's not
528
if (testexpr && adjust_testexpr)
532
params = generate_subquery_params(root,
535
splan->testexpr = convert_testexpr(root,
540
splan->testexpr = testexpr;
543
* We can't convert subplans of ALL_SUBLINK or ANY_SUBLINK types to
544
* initPlans, even when they are uncorrelated or undirect correlated,
545
* because we need to scan the output of the subplan for each outer
546
* tuple. But if it's a not-direct-correlated IN (= ANY) test, we
547
* might be able to use a hashtable to avoid comparing all the tuples.
549
if (subLinkType == ANY_SUBLINK &&
550
splan->parParam == NIL &&
551
subplan_is_hashable(plan) &&
552
testexpr_is_hashable(splan->testexpr))
553
splan->useHashTable = true;
556
* Otherwise, we have the option to tack a MATERIAL node onto the top
557
* of the subplan, to reduce the cost of reading it repeatedly. This
558
* is pointless for a direct-correlated subplan, since we'd have to
559
* recompute its results each time anyway. For uncorrelated/undirect
560
* correlated subplans, we add MATERIAL unless the subplan's top plan
561
* node would materialize its output anyway.
563
else if (splan->parParam == NIL)
567
switch (nodeTag(plan))
572
case T_WorkTableScan:
574
use_material = false;
581
plan = materialize_finished_plan(plan);
584
result = (Node *) splan;
589
* Add the subplan and its rtable to the global lists.
591
root->glob->subplans = lappend(root->glob->subplans, plan);
592
root->glob->subrtables = lappend(root->glob->subrtables, rtable);
593
splan->plan_id = list_length(root->glob->subplans);
596
root->init_plans = lappend(root->init_plans, splan);
599
* A parameterless subplan (not initplan) should be prepared to handle
600
* REWIND efficiently. If it has direct parameters then there's no point
601
* since it'll be reset on each scan anyway; and if it's an initplan then
602
* there's no point since it won't get re-run without parameter changes
603
* anyway. The input of a hashed subplan doesn't need REWIND either.
605
if (splan->parParam == NIL && !isInitPlan && !splan->useHashTable)
606
root->glob->rewindPlanIDs = bms_add_member(root->glob->rewindPlanIDs,
609
/* Lastly, fill in the cost estimates for use later */
610
cost_subplan(root, splan, plan);
616
* generate_subquery_params: build a list of Params representing the output
617
* columns of a sublink's sub-select, given the sub-select's targetlist.
619
* We also return an integer list of the paramids of the Params.
622
generate_subquery_params(PlannerInfo *root, List *tlist, List **paramIds)
631
TargetEntry *tent = (TargetEntry *) lfirst(lc);
637
param = generate_new_param(root,
638
exprType((Node *) tent->expr),
639
exprTypmod((Node *) tent->expr));
640
result = lappend(result, param);
641
ids = lappend_int(ids, param->paramid);
649
* generate_subquery_vars: build a list of Vars representing the output
650
* columns of a sublink's sub-select, given the sub-select's targetlist.
651
* The Vars have the specified varno (RTE index).
654
generate_subquery_vars(PlannerInfo *root, List *tlist, Index varno)
662
TargetEntry *tent = (TargetEntry *) lfirst(lc);
670
exprType((Node *) tent->expr),
671
exprTypmod((Node *) tent->expr),
673
result = lappend(result, var);
680
* convert_testexpr: convert the testexpr given by the parser into
681
* actually executable form. This entails replacing PARAM_SUBLINK Params
682
* with Params or Vars representing the results of the sub-select. The
683
* nodes to be substituted are passed in as the List result from
684
* generate_subquery_params or generate_subquery_vars.
686
* The given testexpr has already been recursively processed by
687
* process_sublinks_mutator. Hence it can no longer contain any
688
* PARAM_SUBLINK Params for lower SubLink nodes; we can safely assume that
689
* any we find are for our own level of SubLink.
692
convert_testexpr(PlannerInfo *root,
696
convert_testexpr_context context;
699
context.subst_nodes = subst_nodes;
700
return convert_testexpr_mutator(testexpr, &context);
704
convert_testexpr_mutator(Node *node,
705
convert_testexpr_context *context)
709
if (IsA(node, Param))
711
Param *param = (Param *) node;
713
if (param->paramkind == PARAM_SUBLINK)
715
if (param->paramid <= 0 ||
716
param->paramid > list_length(context->subst_nodes))
717
elog(ERROR, "unexpected PARAM_SUBLINK ID: %d", param->paramid);
720
* We copy the list item to avoid having doubly-linked
721
* substructure in the modified parse tree. This is probably
722
* unnecessary when it's a Param, but be safe.
724
return (Node *) copyObject(list_nth(context->subst_nodes,
725
param->paramid - 1));
728
return expression_tree_mutator(node,
729
convert_testexpr_mutator,
734
* subplan_is_hashable: can we implement an ANY subplan by hashing?
737
subplan_is_hashable(Plan *plan)
739
double subquery_size;
742
* The estimated size of the subquery result must fit in work_mem. (Note:
743
* we use sizeof(HeapTupleHeaderData) here even though the tuples will
744
* actually be stored as MinimalTuples; this provides some fudge factor
745
* for hashtable overhead.)
747
subquery_size = plan->plan_rows *
748
(MAXALIGN(plan->plan_width) + MAXALIGN(sizeof(HeapTupleHeaderData)));
749
if (subquery_size > work_mem * 1024L)
756
* testexpr_is_hashable: is an ANY SubLink's test expression hashable?
759
testexpr_is_hashable(Node *testexpr)
762
* The testexpr must be a single OpExpr, or an AND-clause containing
765
* The combining operators must be hashable and strict. The need for
766
* hashability is obvious, since we want to use hashing. Without
767
* strictness, behavior in the presence of nulls is too unpredictable. We
768
* actually must assume even more than plain strictness: they can't yield
769
* NULL for non-null inputs, either (see nodeSubplan.c). However, hash
770
* indexes and hash joins assume that too.
772
if (testexpr && IsA(testexpr, OpExpr))
774
if (hash_ok_operator((OpExpr *) testexpr))
777
else if (and_clause(testexpr))
781
foreach(l, ((BoolExpr *) testexpr)->args)
783
Node *andarg = (Node *) lfirst(l);
785
if (!IsA(andarg, OpExpr))
787
if (!hash_ok_operator((OpExpr *) andarg))
797
hash_ok_operator(OpExpr *expr)
799
Oid opid = expr->opno;
801
Form_pg_operator optup;
803
/* quick out if not a binary operator */
804
if (list_length(expr->args) != 2)
806
/* else must look up the operator properties */
807
tup = SearchSysCache(OPEROID,
808
ObjectIdGetDatum(opid),
810
if (!HeapTupleIsValid(tup))
811
elog(ERROR, "cache lookup failed for operator %u", opid);
812
optup = (Form_pg_operator) GETSTRUCT(tup);
813
if (!optup->oprcanhash || !func_strict(optup->oprcode))
815
ReleaseSysCache(tup);
818
ReleaseSysCache(tup);
824
* SS_process_ctes: process a query's WITH list
826
* We plan each interesting WITH item and convert it to an initplan.
827
* A side effect is to fill in root->cte_plan_ids with a list that
828
* parallels root->parse->cteList and provides the subplan ID for
829
* each CTE's initplan.
832
SS_process_ctes(PlannerInfo *root)
836
Assert(root->cte_plan_ids == NIL);
838
foreach(lc, root->parse->cteList)
840
CommonTableExpr *cte = (CommonTableExpr *) lfirst(lc);
843
PlannerInfo *subroot;
850
* Ignore CTEs that are not actually referenced anywhere.
852
if (cte->cterefcount == 0)
854
/* Make a dummy entry in cte_plan_ids */
855
root->cte_plan_ids = lappend_int(root->cte_plan_ids, -1);
860
* Copy the source Query node. Probably not necessary, but let's
861
* keep this similar to make_subplan.
863
subquery = (Query *) copyObject(cte->ctequery);
866
* Generate the plan for the CTE query. Always plan for full
867
* retrieval --- we don't have enough info to predict otherwise.
869
plan = subquery_planner(root->glob, subquery,
871
cte->cterecursive, 0.0,
875
* Make a SubPlan node for it. This is just enough unlike
876
* build_subplan that we can't share code.
878
* Note plan_id isn't set till further down, likewise the cost fields.
880
splan = makeNode(SubPlan);
881
splan->subLinkType = CTE_SUBLINK;
882
splan->testexpr = NULL;
883
splan->paramIds = NIL;
884
get_first_col_type(plan, &splan->firstColType, &splan->firstColTypmod);
885
splan->useHashTable = false;
886
splan->unknownEqFalse = false;
887
splan->setParam = NIL;
888
splan->parParam = NIL;
892
* Make parParam and args lists of param IDs and expressions that
893
* current query level will pass to this child plan. Even though
894
* this is an initplan, there could be side-references to earlier
895
* initplan's outputs, specifically their CTE output parameters.
897
tmpset = bms_copy(plan->extParam);
898
while ((paramid = bms_first_member(tmpset)) >= 0)
900
PlannerParamItem *pitem = list_nth(root->glob->paramlist, paramid);
902
if (pitem->abslevel == root->query_level)
904
prm = (Param *) pitem->item;
905
if (!IsA(prm, Param) ||
906
prm->paramtype != INTERNALOID)
907
elog(ERROR, "bogus local parameter passed to WITH query");
909
splan->parParam = lappend_int(splan->parParam, paramid);
910
splan->args = lappend(splan->args, copyObject(prm));
916
* Assign a param to represent the query output. We only really
917
* care about reserving a parameter ID number.
919
prm = generate_new_param(root, INTERNALOID, -1);
920
splan->setParam = list_make1_int(prm->paramid);
923
* Add the subplan and its rtable to the global lists.
925
root->glob->subplans = lappend(root->glob->subplans, plan);
926
root->glob->subrtables = lappend(root->glob->subrtables,
927
subroot->parse->rtable);
928
splan->plan_id = list_length(root->glob->subplans);
930
root->init_plans = lappend(root->init_plans, splan);
932
root->cte_plan_ids = lappend_int(root->cte_plan_ids, splan->plan_id);
934
/* Lastly, fill in the cost estimates for use later */
935
cost_subplan(root, splan, plan);
940
* convert_ANY_sublink_to_join: try to convert an ANY SubLink to a join
942
* The caller has found an ANY SubLink at the top level of one of the query's
943
* qual clauses, but has not checked the properties of the SubLink further.
944
* Decide whether it is appropriate to process this SubLink in join style.
945
* If so, form a JoinExpr and return it. Return NULL if the SubLink cannot
946
* be converted to a join.
948
* The only non-obvious input parameter is available_rels: this is the set
949
* of query rels that can safely be referenced in the sublink expression.
950
* (We must restrict this to avoid changing the semantics when a sublink
951
* is present in an outer join's ON qual.) The conversion must fail if
952
* the converted qual would reference any but these parent-query relids.
954
* On success, the returned JoinExpr has larg = NULL and rarg = the jointree
955
* item representing the pulled-up subquery. The caller must set larg to
956
* represent the relation(s) on the lefthand side of the new join, and insert
957
* the JoinExpr into the upper query's jointree at an appropriate place
958
* (typically, where the lefthand relation(s) had been). Note that the
959
* passed-in SubLink must also be removed from its original position in the
960
* query quals, since the quals of the returned JoinExpr replace it.
961
* (Notionally, we replace the SubLink with a constant TRUE, then elide the
962
* redundant constant from the qual.)
964
* Side effects of a successful conversion include adding the SubLink's
965
* subselect to the query's rangetable, so that it can be referenced in
966
* the JoinExpr's rarg.
969
convert_ANY_sublink_to_join(PlannerInfo *root, SubLink *sublink,
970
Relids available_rels)
973
Query *parse = root->parse;
974
Query *subselect = (Query *) sublink->subselect;
982
Assert(sublink->subLinkType == ANY_SUBLINK);
985
* The sub-select must not refer to any Vars of the parent query. (Vars of
986
* higher levels should be okay, though.)
988
if (contain_vars_of_level((Node *) subselect, 1))
992
* The test expression must contain some Vars of the parent query,
993
* else it's not gonna be a join. (Note that it won't have Vars
994
* referring to the subquery, rather Params.)
996
upper_varnos = pull_varnos(sublink->testexpr);
997
if (bms_is_empty(upper_varnos))
1001
* However, it can't refer to anything outside available_rels.
1003
if (!bms_is_subset(upper_varnos, available_rels))
1007
* The combining operators and left-hand expressions mustn't be volatile.
1009
if (contain_volatile_functions(sublink->testexpr))
1013
* Okay, pull up the sub-select into upper range table.
1015
* We rely here on the assumption that the outer query has no references
1016
* to the inner (necessarily true, other than the Vars that we build
1017
* below). Therefore this is a lot easier than what pull_up_subqueries has
1020
rte = addRangeTableEntryForSubquery(NULL,
1022
makeAlias("ANY_subquery", NIL),
1024
parse->rtable = lappend(parse->rtable, rte);
1025
rtindex = list_length(parse->rtable);
1028
* Form a RangeTblRef for the pulled-up sub-select.
1030
rtr = makeNode(RangeTblRef);
1031
rtr->rtindex = rtindex;
1034
* Build a list of Vars representing the subselect outputs.
1036
subquery_vars = generate_subquery_vars(root,
1037
subselect->targetList,
1041
* Build the new join's qual expression, replacing Params with these Vars.
1043
quals = convert_testexpr(root, sublink->testexpr, subquery_vars);
1046
* And finally, build the JoinExpr node.
1048
result = makeNode(JoinExpr);
1049
result->jointype = JOIN_SEMI;
1050
result->isNatural = false;
1051
result->larg = NULL; /* caller must fill this in */
1052
result->rarg = (Node *) rtr;
1053
result->using = NIL;
1054
result->quals = quals;
1055
result->alias = NULL;
1056
result->rtindex = 0; /* we don't need an RTE for it */
1062
* convert_EXISTS_sublink_to_join: try to convert an EXISTS SubLink to a join
1064
* The API of this function is identical to convert_ANY_sublink_to_join's,
1065
* except that we also support the case where the caller has found NOT EXISTS,
1066
* so we need an additional input parameter "under_not".
1069
convert_EXISTS_sublink_to_join(PlannerInfo *root, SubLink *sublink,
1070
bool under_not, Relids available_rels)
1073
Query *parse = root->parse;
1074
Query *subselect = (Query *) sublink->subselect;
1078
Relids clause_varnos;
1079
Relids upper_varnos;
1081
Assert(sublink->subLinkType == EXISTS_SUBLINK);
1084
* Copy the subquery so we can modify it safely (see comments in
1087
subselect = (Query *) copyObject(subselect);
1090
* See if the subquery can be simplified based on the knowledge that
1091
* it's being used in EXISTS(). If we aren't able to get rid of its
1092
* targetlist, we have to fail, because the pullup operation leaves
1093
* us with noplace to evaluate the targetlist.
1095
if (!simplify_EXISTS_query(subselect))
1099
* The subquery must have a nonempty jointree, else we won't have a join.
1101
if (subselect->jointree->fromlist == NIL)
1105
* Separate out the WHERE clause. (We could theoretically also remove
1106
* top-level plain JOIN/ON clauses, but it's probably not worth the
1109
whereClause = subselect->jointree->quals;
1110
subselect->jointree->quals = NULL;
1113
* The rest of the sub-select must not refer to any Vars of the parent
1114
* query. (Vars of higher levels should be okay, though.)
1116
if (contain_vars_of_level((Node *) subselect, 1))
1120
* On the other hand, the WHERE clause must contain some Vars of the
1121
* parent query, else it's not gonna be a join.
1123
if (!contain_vars_of_level(whereClause, 1))
1127
* We don't risk optimizing if the WHERE clause is volatile, either.
1129
if (contain_volatile_functions(whereClause))
1133
* Prepare to pull up the sub-select into top range table.
1135
* We rely here on the assumption that the outer query has no references
1136
* to the inner (necessarily true). Therefore this is a lot easier than
1137
* what pull_up_subqueries has to go through.
1139
* In fact, it's even easier than what convert_ANY_sublink_to_join has
1140
* to do. The machinations of simplify_EXISTS_query ensured that there
1141
* is nothing interesting in the subquery except an rtable and jointree,
1142
* and even the jointree FromExpr no longer has quals. So we can just
1143
* append the rtable to our own and use the FromExpr in our jointree.
1144
* But first, adjust all level-zero varnos in the subquery to account
1145
* for the rtable merger.
1147
rtoffset = list_length(parse->rtable);
1148
OffsetVarNodes((Node *) subselect, rtoffset, 0);
1149
OffsetVarNodes(whereClause, rtoffset, 0);
1152
* Upper-level vars in subquery will now be one level closer to their
1153
* parent than before; in particular, anything that had been level 1
1154
* becomes level zero.
1156
IncrementVarSublevelsUp((Node *) subselect, -1, 1);
1157
IncrementVarSublevelsUp(whereClause, -1, 1);
1160
* Now that the WHERE clause is adjusted to match the parent query
1161
* environment, we can easily identify all the level-zero rels it uses.
1162
* The ones <= rtoffset belong to the upper query; the ones > rtoffset
1165
clause_varnos = pull_varnos(whereClause);
1166
upper_varnos = NULL;
1167
while ((varno = bms_first_member(clause_varnos)) >= 0)
1169
if (varno <= rtoffset)
1170
upper_varnos = bms_add_member(upper_varnos, varno);
1172
bms_free(clause_varnos);
1173
Assert(!bms_is_empty(upper_varnos));
1176
* Now that we've got the set of upper-level varnos, we can make the
1177
* last check: only available_rels can be referenced.
1179
if (!bms_is_subset(upper_varnos, available_rels))
1182
/* Now we can attach the modified subquery rtable to the parent */
1183
parse->rtable = list_concat(parse->rtable, subselect->rtable);
1186
* And finally, build the JoinExpr node.
1188
result = makeNode(JoinExpr);
1189
result->jointype = under_not ? JOIN_ANTI : JOIN_SEMI;
1190
result->isNatural = false;
1191
result->larg = NULL; /* caller must fill this in */
1192
/* flatten out the FromExpr node if it's useless */
1193
if (list_length(subselect->jointree->fromlist) == 1)
1194
result->rarg = (Node *) linitial(subselect->jointree->fromlist);
1196
result->rarg = (Node *) subselect->jointree;
1197
result->using = NIL;
1198
result->quals = whereClause;
1199
result->alias = NULL;
1200
result->rtindex = 0; /* we don't need an RTE for it */
1206
* simplify_EXISTS_query: remove any useless stuff in an EXISTS's subquery
1208
* The only thing that matters about an EXISTS query is whether it returns
1209
* zero or more than zero rows. Therefore, we can remove certain SQL features
1210
* that won't affect that. The only part that is really likely to matter in
1211
* typical usage is simplifying the targetlist: it's a common habit to write
1212
* "SELECT * FROM" even though there is no need to evaluate any columns.
1214
* Note: by suppressing the targetlist we could cause an observable behavioral
1215
* change, namely that any errors that might occur in evaluating the tlist
1216
* won't occur, nor will other side-effects of volatile functions. This seems
1217
* unlikely to bother anyone in practice.
1219
* Returns TRUE if was able to discard the targetlist, else FALSE.
1222
simplify_EXISTS_query(Query *query)
1225
* We don't try to simplify at all if the query uses set operations,
1226
* aggregates, HAVING, LIMIT/OFFSET, or FOR UPDATE/SHARE; none of these
1227
* seem likely in normal usage and their possible effects are complex.
1229
if (query->commandType != CMD_SELECT ||
1230
query->intoClause ||
1231
query->setOperations ||
1233
query->hasWindowFuncs ||
1234
query->havingQual ||
1235
query->limitOffset ||
1236
query->limitCount ||
1241
* Mustn't throw away the targetlist if it contains set-returning
1242
* functions; those could affect whether zero rows are returned!
1244
if (expression_returns_set((Node *) query->targetList))
1248
* Otherwise, we can throw away the targetlist, as well as any GROUP,
1249
* WINDOW, DISTINCT, and ORDER BY clauses; none of those clauses will
1250
* change a nonzero-rows result to zero rows or vice versa. (Furthermore,
1251
* since our parsetree representation of these clauses depends on the
1252
* targetlist, we'd better throw them away if we drop the targetlist.)
1254
query->targetList = NIL;
1255
query->groupClause = NIL;
1256
query->windowClause = NIL;
1257
query->distinctClause = NIL;
1258
query->sortClause = NIL;
1259
query->hasDistinctOn = false;
1265
* convert_EXISTS_to_ANY: try to convert EXISTS to a hashable ANY sublink
1267
* The subselect is expected to be a fresh copy that we can munge up,
1268
* and to have been successfully passed through simplify_EXISTS_query.
1270
* On success, the modified subselect is returned, and we store a suitable
1271
* upper-level test expression at *testexpr, plus a list of the subselect's
1272
* output Params at *paramIds. (The test expression is already Param-ified
1273
* and hence need not go through convert_testexpr, which is why we have to
1274
* deal with the Param IDs specially.)
1276
* On failure, returns NULL.
1279
convert_EXISTS_to_ANY(PlannerInfo *root, Query *subselect,
1280
Node **testexpr, List **paramIds)
1296
* Query must not require a targetlist, since we have to insert a new one.
1297
* Caller should have dealt with the case already.
1299
Assert(subselect->targetList == NIL);
1302
* Separate out the WHERE clause. (We could theoretically also remove
1303
* top-level plain JOIN/ON clauses, but it's probably not worth the
1306
whereClause = subselect->jointree->quals;
1307
subselect->jointree->quals = NULL;
1310
* The rest of the sub-select must not refer to any Vars of the parent
1311
* query. (Vars of higher levels should be okay, though.)
1313
* Note: we need not check for Aggrefs separately because we know the
1314
* sub-select is as yet unoptimized; any uplevel Aggref must therefore
1315
* contain an uplevel Var reference. This is not the case below ...
1317
if (contain_vars_of_level((Node *) subselect, 1))
1321
* We don't risk optimizing if the WHERE clause is volatile, either.
1323
if (contain_volatile_functions(whereClause))
1327
* Clean up the WHERE clause by doing const-simplification etc on it.
1328
* Aside from simplifying the processing we're about to do, this is
1329
* important for being able to pull chunks of the WHERE clause up into
1330
* the parent query. Since we are invoked partway through the parent's
1331
* preprocess_expression() work, earlier steps of preprocess_expression()
1332
* wouldn't get applied to the pulled-up stuff unless we do them here.
1333
* For the parts of the WHERE clause that get put back into the child
1334
* query, this work is partially duplicative, but it shouldn't hurt.
1336
* Note: we do not run flatten_join_alias_vars. This is OK because
1337
* any parent aliases were flattened already, and we're not going to
1338
* pull any child Vars (of any description) into the parent.
1340
* Note: passing the parent's root to eval_const_expressions is technically
1341
* wrong, but we can get away with it since only the boundParams (if any)
1342
* are used, and those would be the same in a subroot.
1344
whereClause = eval_const_expressions(root, whereClause);
1345
whereClause = (Node *) canonicalize_qual((Expr *) whereClause);
1346
whereClause = (Node *) make_ands_implicit((Expr *) whereClause);
1349
* We now have a flattened implicit-AND list of clauses, which we
1350
* try to break apart into "outervar = innervar" hash clauses.
1351
* Anything that can't be broken apart just goes back into the
1352
* newWhere list. Note that we aren't trying hard yet to ensure
1353
* that we have only outer or only inner on each side; we'll check
1354
* that if we get to the end.
1356
leftargs = rightargs = opids = newWhere = NIL;
1357
foreach(lc, (List *) whereClause)
1359
OpExpr *expr = (OpExpr *) lfirst(lc);
1361
if (IsA(expr, OpExpr) &&
1362
hash_ok_operator(expr))
1364
Node *leftarg = (Node *) linitial(expr->args);
1365
Node *rightarg = (Node *) lsecond(expr->args);
1367
if (contain_vars_of_level(leftarg, 1))
1369
leftargs = lappend(leftargs, leftarg);
1370
rightargs = lappend(rightargs, rightarg);
1371
opids = lappend_oid(opids, expr->opno);
1374
if (contain_vars_of_level(rightarg, 1))
1377
* We must commute the clause to put the outer var on the
1378
* left, because the hashing code in nodeSubplan.c expects
1379
* that. This probably shouldn't ever fail, since hashable
1380
* operators ought to have commutators, but be paranoid.
1382
expr->opno = get_commutator(expr->opno);
1383
if (OidIsValid(expr->opno) && hash_ok_operator(expr))
1385
leftargs = lappend(leftargs, rightarg);
1386
rightargs = lappend(rightargs, leftarg);
1387
opids = lappend_oid(opids, expr->opno);
1390
/* If no commutator, no chance to optimize the WHERE clause */
1394
/* Couldn't handle it as a hash clause */
1395
newWhere = lappend(newWhere, expr);
1399
* If we didn't find anything we could convert, fail.
1401
if (leftargs == NIL)
1405
* There mustn't be any parent Vars or Aggs in the stuff that we intend to
1406
* put back into the child query. Note: you might think we don't need to
1407
* check for Aggs separately, because an uplevel Agg must contain an
1408
* uplevel Var in its argument. But it is possible that the uplevel Var
1409
* got optimized away by eval_const_expressions. Consider
1411
* SUM(CASE WHEN false THEN uplevelvar ELSE 0 END)
1413
if (contain_vars_of_level((Node *) newWhere, 1) ||
1414
contain_vars_of_level((Node *) rightargs, 1))
1416
if (root->parse->hasAggs &&
1417
(contain_aggs_of_level((Node *) newWhere, 1) ||
1418
contain_aggs_of_level((Node *) rightargs, 1)))
1422
* And there can't be any child Vars in the stuff we intend to pull up.
1423
* (Note: we'd need to check for child Aggs too, except we know the
1424
* child has no aggs at all because of simplify_EXISTS_query's check.
1425
* The same goes for window functions.)
1427
if (contain_vars_of_level((Node *) leftargs, 0))
1431
* Also reject sublinks in the stuff we intend to pull up. (It might be
1432
* possible to support this, but doesn't seem worth the complication.)
1434
if (contain_subplans((Node *) leftargs))
1438
* Okay, adjust the sublevelsup in the stuff we're pulling up.
1440
IncrementVarSublevelsUp((Node *) leftargs, -1, 1);
1443
* Put back any child-level-only WHERE clauses.
1446
subselect->jointree->quals = (Node *) make_ands_explicit(newWhere);
1449
* Build a new targetlist for the child that emits the expressions
1450
* we need. Concurrently, build a testexpr for the parent using
1451
* Params to reference the child outputs. (Since we generate Params
1452
* directly here, there will be no need to convert the testexpr in
1455
tlist = testlist = paramids = NIL;
1457
/* there's no "for3" so we have to chase one of the lists manually */
1458
oc = list_head(opids);
1459
forboth(lc, leftargs, rc, rightargs)
1461
Node *leftarg = (Node *) lfirst(lc);
1462
Node *rightarg = (Node *) lfirst(rc);
1463
Oid opid = lfirst_oid(oc);
1467
param = generate_new_param(root,
1469
exprTypmod(rightarg));
1470
tlist = lappend(tlist,
1471
makeTargetEntry((Expr *) rightarg,
1475
testlist = lappend(testlist,
1476
make_opclause(opid, BOOLOID, false,
1477
(Expr *) leftarg, (Expr *) param));
1478
paramids = lappend_int(paramids, param->paramid);
1481
/* Put everything where it should go, and we're done */
1482
subselect->targetList = tlist;
1483
*testexpr = (Node *) make_ands_explicit(testlist);
1484
*paramIds = paramids;
1491
* Replace correlation vars (uplevel vars) with Params.
1493
* Uplevel aggregates are replaced, too.
1495
* Note: it is critical that this runs immediately after SS_process_sublinks.
1496
* Since we do not recurse into the arguments of uplevel aggregates, they will
1497
* get copied to the appropriate subplan args list in the parent query with
1498
* uplevel vars not replaced by Params, but only adjusted in level (see
1499
* replace_outer_agg). That's exactly what we want for the vars of the parent
1500
* level --- but if an aggregate's argument contains any further-up variables,
1501
* they have to be replaced with Params in their turn. That will happen when
1502
* the parent level runs SS_replace_correlation_vars. Therefore it must do
1503
* so after expanding its sublinks to subplans. And we don't want any steps
1504
* in between, else those steps would never get applied to the aggregate
1505
* argument expressions, either in the parent or the child level.
1508
SS_replace_correlation_vars(PlannerInfo *root, Node *expr)
1510
/* No setup needed for tree walk, so away we go */
1511
return replace_correlation_vars_mutator(expr, root);
1515
replace_correlation_vars_mutator(Node *node, PlannerInfo *root)
1521
if (((Var *) node)->varlevelsup > 0)
1522
return (Node *) replace_outer_var(root, (Var *) node);
1524
if (IsA(node, Aggref))
1526
if (((Aggref *) node)->agglevelsup > 0)
1527
return (Node *) replace_outer_agg(root, (Aggref *) node);
1529
return expression_tree_mutator(node,
1530
replace_correlation_vars_mutator,
1535
* Expand SubLinks to SubPlans in the given expression.
1537
* The isQual argument tells whether or not this expression is a WHERE/HAVING
1538
* qualifier expression. If it is, any sublinks appearing at top level need
1539
* not distinguish FALSE from UNKNOWN return values.
1542
SS_process_sublinks(PlannerInfo *root, Node *expr, bool isQual)
1544
process_sublinks_context context;
1546
context.root = root;
1547
context.isTopQual = isQual;
1548
return process_sublinks_mutator(expr, &context);
1552
process_sublinks_mutator(Node *node, process_sublinks_context *context)
1554
process_sublinks_context locContext;
1556
locContext.root = context->root;
1560
if (IsA(node, SubLink))
1562
SubLink *sublink = (SubLink *) node;
1566
* First, recursively process the lefthand-side expressions, if any.
1567
* They're not top-level anymore.
1569
locContext.isTopQual = false;
1570
testexpr = process_sublinks_mutator(sublink->testexpr, &locContext);
1573
* Now build the SubPlan node and make the expr to return.
1575
return make_subplan(context->root,
1576
(Query *) sublink->subselect,
1577
sublink->subLinkType,
1579
context->isTopQual);
1583
* We should never see a SubPlan expression in the input (since this is
1584
* the very routine that creates 'em to begin with). We shouldn't find
1585
* ourselves invoked directly on a Query, either.
1587
Assert(!IsA(node, SubPlan));
1588
Assert(!IsA(node, AlternativeSubPlan));
1589
Assert(!IsA(node, Query));
1592
* Because make_subplan() could return an AND or OR clause, we have to
1593
* take steps to preserve AND/OR flatness of a qual. We assume the input
1594
* has been AND/OR flattened and so we need no recursion here.
1596
* (Due to the coding here, we will not get called on the List subnodes of
1597
* an AND; and the input is *not* yet in implicit-AND format. So no check
1598
* is needed for a bare List.)
1600
* Anywhere within the top-level AND/OR clause structure, we can tell
1601
* make_subplan() that NULL and FALSE are interchangeable. So isTopQual
1602
* propagates down in both cases. (Note that this is unlike the meaning
1603
* of "top level qual" used in most other places in Postgres.)
1605
if (and_clause(node))
1607
List *newargs = NIL;
1610
/* Still at qual top-level */
1611
locContext.isTopQual = context->isTopQual;
1613
foreach(l, ((BoolExpr *) node)->args)
1617
newarg = process_sublinks_mutator(lfirst(l), &locContext);
1618
if (and_clause(newarg))
1619
newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1621
newargs = lappend(newargs, newarg);
1623
return (Node *) make_andclause(newargs);
1626
if (or_clause(node))
1628
List *newargs = NIL;
1631
/* Still at qual top-level */
1632
locContext.isTopQual = context->isTopQual;
1634
foreach(l, ((BoolExpr *) node)->args)
1638
newarg = process_sublinks_mutator(lfirst(l), &locContext);
1639
if (or_clause(newarg))
1640
newargs = list_concat(newargs, ((BoolExpr *) newarg)->args);
1642
newargs = lappend(newargs, newarg);
1644
return (Node *) make_orclause(newargs);
1648
* If we recurse down through anything other than an AND or OR node,
1649
* we are definitely not at top qual level anymore.
1651
locContext.isTopQual = false;
1653
return expression_tree_mutator(node,
1654
process_sublinks_mutator,
1655
(void *) &locContext);
1659
* SS_finalize_plan - do final sublink processing for a completed Plan.
1661
* This recursively computes the extParam and allParam sets for every Plan
1662
* node in the given plan tree. It also optionally attaches any previously
1663
* generated InitPlans to the top plan node. (Any InitPlans should already
1664
* have been put through SS_finalize_plan.)
1667
SS_finalize_plan(PlannerInfo *root, Plan *plan, bool attach_initplans)
1669
Bitmapset *valid_params,
1677
* Examine any initPlans to determine the set of external params they
1678
* reference, the set of output params they supply, and their total cost.
1679
* We'll use at least some of this info below. (Note we are assuming that
1680
* finalize_plan doesn't touch the initPlans.)
1682
* In the case where attach_initplans is false, we are assuming that the
1683
* existing initPlans are siblings that might supply params needed by the
1686
initExtParam = initSetParam = NULL;
1688
foreach(l, root->init_plans)
1690
SubPlan *initsubplan = (SubPlan *) lfirst(l);
1691
Plan *initplan = planner_subplan_get_plan(root, initsubplan);
1694
initExtParam = bms_add_members(initExtParam, initplan->extParam);
1695
foreach(l2, initsubplan->setParam)
1697
initSetParam = bms_add_member(initSetParam, lfirst_int(l2));
1699
initplan_cost += initsubplan->startup_cost + initsubplan->per_call_cost;
1703
* Now determine the set of params that are validly referenceable in this
1704
* query level; to wit, those available from outer query levels plus the
1705
* output parameters of any initPlans. (We do not include output
1706
* parameters of regular subplans. Those should only appear within the
1707
* testexpr of SubPlan nodes, and are taken care of locally within
1708
* finalize_primnode.)
1710
* Note: this is a bit overly generous since some parameters of upper
1711
* query levels might belong to query subtrees that don't include this
1712
* query. However, valid_params is only a debugging crosscheck, so it
1713
* doesn't seem worth expending lots of cycles to try to be exact.
1715
valid_params = bms_copy(initSetParam);
1717
foreach(l, root->glob->paramlist)
1719
PlannerParamItem *pitem = (PlannerParamItem *) lfirst(l);
1721
if (pitem->abslevel < root->query_level)
1723
/* valid outer-level parameter */
1724
valid_params = bms_add_member(valid_params, paramid);
1729
/* Also include the recursion working table, if any */
1730
if (root->wt_param_id >= 0)
1731
valid_params = bms_add_member(valid_params, root->wt_param_id);
1734
* Now recurse through plan tree.
1736
(void) finalize_plan(root, plan, valid_params);
1738
bms_free(valid_params);
1741
* Finally, attach any initPlans to the topmost plan node, and add their
1742
* extParams to the topmost node's, too. However, any setParams of the
1743
* initPlans should not be present in the topmost node's extParams, only
1744
* in its allParams. (As of PG 8.1, it's possible that some initPlans
1745
* have extParams that are setParams of other initPlans, so we have to
1746
* take care of this situation explicitly.)
1748
* We also add the eval cost of each initPlan to the startup cost of the
1749
* top node. This is a conservative overestimate, since in fact each
1750
* initPlan might be executed later than plan startup, or even not at all.
1752
if (attach_initplans)
1754
plan->initPlan = root->init_plans;
1755
root->init_plans = NIL; /* make sure they're not attached twice */
1757
/* allParam must include all these params */
1758
plan->allParam = bms_add_members(plan->allParam, initExtParam);
1759
plan->allParam = bms_add_members(plan->allParam, initSetParam);
1760
/* extParam must include any child extParam */
1761
plan->extParam = bms_add_members(plan->extParam, initExtParam);
1762
/* but extParam shouldn't include any setParams */
1763
plan->extParam = bms_del_members(plan->extParam, initSetParam);
1764
/* ensure extParam is exactly NULL if it's empty */
1765
if (bms_is_empty(plan->extParam))
1766
plan->extParam = NULL;
1768
plan->startup_cost += initplan_cost;
1769
plan->total_cost += initplan_cost;
1774
* Recursive processing of all nodes in the plan tree
1776
* The return value is the computed allParam set for the given Plan node.
1777
* This is just an internal notational convenience.
1780
finalize_plan(PlannerInfo *root, Plan *plan, Bitmapset *valid_params)
1782
finalize_primnode_context context;
1787
context.root = root;
1788
context.paramids = NULL; /* initialize set to empty */
1791
* When we call finalize_primnode, context.paramids sets are automatically
1792
* merged together. But when recursing to self, we have to do it the hard
1793
* way. We want the paramids set to include params in subplans as well as
1797
/* Find params in targetlist and qual */
1798
finalize_primnode((Node *) plan->targetlist, &context);
1799
finalize_primnode((Node *) plan->qual, &context);
1801
/* Check additional node-type-specific fields */
1802
switch (nodeTag(plan))
1805
finalize_primnode(((Result *) plan)->resconstantqual,
1810
finalize_primnode((Node *) ((IndexScan *) plan)->indexqual,
1814
* we need not look at indexqualorig, since it will have the same
1815
* param references as indexqual.
1819
case T_BitmapIndexScan:
1820
finalize_primnode((Node *) ((BitmapIndexScan *) plan)->indexqual,
1824
* we need not look at indexqualorig, since it will have the same
1825
* param references as indexqual.
1829
case T_BitmapHeapScan:
1830
finalize_primnode((Node *) ((BitmapHeapScan *) plan)->bitmapqualorig,
1835
finalize_primnode((Node *) ((TidScan *) plan)->tidquals,
1839
case T_SubqueryScan:
1842
* In a SubqueryScan, SS_finalize_plan has already been run on the
1843
* subplan by the inner invocation of subquery_planner, so there's
1844
* no need to do it again. Instead, just pull out the subplan's
1845
* extParams list, which represents the params it needs from my
1846
* level and higher levels.
1848
context.paramids = bms_add_members(context.paramids,
1849
((SubqueryScan *) plan)->subplan->extParam);
1852
case T_FunctionScan:
1853
finalize_primnode(((FunctionScan *) plan)->funcexpr,
1858
finalize_primnode((Node *) ((ValuesScan *) plan)->values_lists,
1864
bms_add_member(context.paramids,
1865
((CteScan *) plan)->cteParam);
1868
case T_WorkTableScan:
1870
bms_add_member(context.paramids,
1871
((WorkTableScan *) plan)->wtParam);
1878
foreach(l, ((Append *) plan)->appendplans)
1881
bms_add_members(context.paramids,
1893
foreach(l, ((BitmapAnd *) plan)->bitmapplans)
1896
bms_add_members(context.paramids,
1908
foreach(l, ((BitmapOr *) plan)->bitmapplans)
1911
bms_add_members(context.paramids,
1920
finalize_primnode((Node *) ((Join *) plan)->joinqual,
1925
finalize_primnode((Node *) ((Join *) plan)->joinqual,
1927
finalize_primnode((Node *) ((MergeJoin *) plan)->mergeclauses,
1932
finalize_primnode((Node *) ((Join *) plan)->joinqual,
1934
finalize_primnode((Node *) ((HashJoin *) plan)->hashclauses,
1939
finalize_primnode(((Limit *) plan)->limitOffset,
1941
finalize_primnode(((Limit *) plan)->limitCount,
1945
case T_RecursiveUnion:
1958
elog(ERROR, "unrecognized node type: %d",
1959
(int) nodeTag(plan));
1962
/* Process left and right child plans, if any */
1963
context.paramids = bms_add_members(context.paramids,
1968
context.paramids = bms_add_members(context.paramids,
1974
* RecursiveUnion *generates* its worktable param, so don't bubble that up
1976
if (IsA(plan, RecursiveUnion))
1978
context.paramids = bms_del_member(context.paramids,
1979
((RecursiveUnion *) plan)->wtParam);
1982
/* Now we have all the paramids */
1984
if (!bms_is_subset(context.paramids, valid_params))
1985
elog(ERROR, "plan should not reference subplan's variable");
1988
* Note: by definition, extParam and allParam should have the same value
1989
* in any plan node that doesn't have child initPlans. We set them
1990
* equal here, and later SS_finalize_plan will update them properly
1991
* in node(s) that it attaches initPlans to.
1993
* For speed at execution time, make sure extParam/allParam are actually
1994
* NULL if they are empty sets.
1996
if (bms_is_empty(context.paramids))
1998
plan->extParam = NULL;
1999
plan->allParam = NULL;
2003
plan->extParam = context.paramids;
2004
plan->allParam = bms_copy(context.paramids);
2007
return plan->allParam;
2011
* finalize_primnode: add IDs of all PARAM_EXEC params appearing in the given
2012
* expression tree to the result set.
2015
finalize_primnode(Node *node, finalize_primnode_context *context)
2019
if (IsA(node, Param))
2021
if (((Param *) node)->paramkind == PARAM_EXEC)
2023
int paramid = ((Param *) node)->paramid;
2025
context->paramids = bms_add_member(context->paramids, paramid);
2027
return false; /* no more to do here */
2029
if (IsA(node, SubPlan))
2031
SubPlan *subplan = (SubPlan *) node;
2032
Plan *plan = planner_subplan_get_plan(context->root, subplan);
2034
Bitmapset *subparamids;
2036
/* Recurse into the testexpr, but not into the Plan */
2037
finalize_primnode(subplan->testexpr, context);
2040
* Remove any param IDs of output parameters of the subplan that were
2041
* referenced in the testexpr. These are not interesting for
2042
* parameter change signaling since we always re-evaluate the subplan.
2043
* Note that this wouldn't work too well if there might be uses of the
2044
* same param IDs elsewhere in the plan, but that can't happen because
2045
* generate_new_param never tries to merge params.
2047
foreach(lc, subplan->paramIds)
2049
context->paramids = bms_del_member(context->paramids,
2053
/* Also examine args list */
2054
finalize_primnode((Node *) subplan->args, context);
2057
* Add params needed by the subplan to paramids, but excluding those
2058
* we will pass down to it.
2060
subparamids = bms_copy(plan->extParam);
2061
foreach(lc, subplan->parParam)
2063
subparamids = bms_del_member(subparamids, lfirst_int(lc));
2065
context->paramids = bms_join(context->paramids, subparamids);
2067
return false; /* no more to do here */
2069
return expression_tree_walker(node, finalize_primnode,
2074
* SS_make_initplan_from_plan - given a plan tree, make it an InitPlan
2076
* The plan is expected to return a scalar value of the indicated type.
2077
* We build an EXPR_SUBLINK SubPlan node and put it into the initplan
2078
* list for the current query level. A Param that represents the initplan's
2079
* output is returned.
2081
* We assume the plan hasn't been put through SS_finalize_plan.
2084
SS_make_initplan_from_plan(PlannerInfo *root, Plan *plan,
2085
Oid resulttype, int32 resulttypmod)
2091
* We must run SS_finalize_plan(), since that's normally done before a
2092
* subplan gets put into the initplan list. Tell it not to attach any
2093
* pre-existing initplans to this one, since they are siblings not
2094
* children of this initplan. (This is something else that could perhaps
2095
* be cleaner if we did extParam/allParam processing in setrefs.c instead
2096
* of here? See notes for materialize_finished_plan.)
2100
* Build extParam/allParam sets for plan nodes.
2102
SS_finalize_plan(root, plan, false);
2105
* Add the subplan and its rtable to the global lists.
2107
root->glob->subplans = lappend(root->glob->subplans,
2109
root->glob->subrtables = lappend(root->glob->subrtables,
2110
root->parse->rtable);
2113
* Create a SubPlan node and add it to the outer list of InitPlans.
2114
* Note it has to appear after any other InitPlans it might depend on
2115
* (see comments in ExecReScan).
2117
node = makeNode(SubPlan);
2118
node->subLinkType = EXPR_SUBLINK;
2119
get_first_col_type(plan, &node->firstColType, &node->firstColTypmod);
2120
node->plan_id = list_length(root->glob->subplans);
2122
root->init_plans = lappend(root->init_plans, node);
2125
* The node can't have any inputs (since it's an initplan), so the
2126
* parParam and args lists remain empty.
2129
cost_subplan(root, node, plan);
2132
* Make a Param that will be the subplan's output.
2134
prm = generate_new_param(root, resulttype, resulttypmod);
2135
node->setParam = list_make1_int(prm->paramid);
added
removed
src/backend/optimizer/plan/subselect.c
