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Revise the planner's handling of "pseudoconstant" WHERE clauses, that is

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clauses containing no variables and no volatile functions.  Such a clause
can be used as a one-time qual in a gating Result plan node, to suppress
plan execution entirely when it is false.  Even when the clause is true,
putting it in a gating node wins by avoiding repeated evaluation of the
clause.  In previous PG releases, query_planner() would do this for
pseudoconstant clauses appearing at the top level of the jointree, but
there was no ability to generate a gating Result deeper in the plan tree.
To fix it, get rid of the special case in query_planner(), and instead
process pseudoconstant clauses through the normal RestrictInfo qual
distribution mechanism.  When a pseudoconstant clause is found attached to
a path node in create_plan(), pull it out and generate a gating Result at
that point.  This requires special-casing pseudoconstants in selectivity
estimation and cost_qual_eval, but on the whole it's pretty clean.
It probably even makes the planner a bit faster than before for the normal
case of no pseudoconstants, since removing pull_constant_clauses saves one
useless traversal of the qual tree.  Per gripe from Phil Frost.
This commit is contained in:
Tom Lane 2006-07-01 18:38:33 +00:00
parent 68628fc38e
commit cffd89ca73
20 changed files with 464 additions and 294 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
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 1.337 2006/06/27 03:43:19 momjian Exp $
* $PostgreSQL: pgsql/src/backend/nodes/copyfuncs.c,v 1.338 2006/07/01 18:38:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1264,6 +1264,7 @@ _copyRestrictInfo(RestrictInfo *from)
COPY_SCALAR_FIELD(is_pushed_down);
COPY_SCALAR_FIELD(outerjoin_delayed);
COPY_SCALAR_FIELD(can_join);
COPY_SCALAR_FIELD(pseudoconstant);
COPY_BITMAPSET_FIELD(clause_relids);
COPY_BITMAPSET_FIELD(required_relids);
COPY_BITMAPSET_FIELD(left_relids);

7
src/backend/nodes/outfuncs.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.274 2006/04/30 18:30:39 tgl Exp $
* $PostgreSQL: pgsql/src/backend/nodes/outfuncs.c,v 1.275 2006/07/01 18:38:32 tgl Exp $
*
* NOTES
* Every node type that can appear in stored rules' parsetrees *must*
@ -1107,8 +1107,7 @@ _outResultPath(StringInfo str, ResultPath *node)
_outPathInfo(str, (Path *) node);
WRITE_NODE_FIELD(subpath);
WRITE_NODE_FIELD(constantqual);
WRITE_NODE_FIELD(quals);
}
static void
@ -1185,6 +1184,7 @@ _outPlannerInfo(StringInfo str, PlannerInfo *node)
WRITE_BOOL_FIELD(hasJoinRTEs);
WRITE_BOOL_FIELD(hasOuterJoins);
WRITE_BOOL_FIELD(hasHavingQual);
WRITE_BOOL_FIELD(hasPseudoConstantQuals);
}
static void
@ -1252,6 +1252,7 @@ _outRestrictInfo(StringInfo str, RestrictInfo *node)
WRITE_BOOL_FIELD(is_pushed_down);
WRITE_BOOL_FIELD(outerjoin_delayed);
WRITE_BOOL_FIELD(can_join);
WRITE_BOOL_FIELD(pseudoconstant);
WRITE_BITMAPSET_FIELD(clause_relids);
WRITE_BITMAPSET_FIELD(required_relids);
WRITE_BITMAPSET_FIELD(left_relids);

2
src/backend/optimizer/README
View File

@ -329,7 +329,7 @@ RelOptInfo - a relation or joined relations
BitmapHeapPath - top of a bitmapped index scan
TidPath - scan by CTID
AppendPath - append multiple subpaths together
ResultPath - a Result plan node (used for variable-free tlist or qual)
ResultPath - a Result plan node (used for FROM-less SELECT)
MaterialPath - a Material plan node
UniquePath - remove duplicate rows
NestPath - nested-loop joins

10
src/backend/optimizer/path/allpaths.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.146 2006/05/02 04:34:18 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/allpaths.c,v 1.147 2006/07/01 18:38:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -446,7 +446,9 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
* There are several cases where we cannot push down clauses. Restrictions
* involving the subquery are checked by subquery_is_pushdown_safe().
* Restrictions on individual clauses are checked by
* qual_is_pushdown_safe().
* qual_is_pushdown_safe(). Also, we don't want to push down
* pseudoconstant clauses; better to have the gating node above the
* subquery.
*
* Non-pushed-down clauses will get evaluated as qpquals of the
* SubqueryScan node.
@ -466,7 +468,8 @@ set_subquery_pathlist(PlannerInfo *root, RelOptInfo *rel,
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
Node *clause = (Node *) rinfo->clause;
if (qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
if (!rinfo->pseudoconstant &&
qual_is_pushdown_safe(subquery, rti, clause, differentTypes))
{
/* Push it down */
subquery_push_qual(subquery, rte, rti, clause);
@ -1066,7 +1069,6 @@ print_path(PlannerInfo *root, Path *path, int indent)
break;
case T_ResultPath:
ptype = "Result";
subpath = ((ResultPath *) path)->subpath;
break;
case T_MaterialPath:
ptype = "Material";

34
src/backend/optimizer/path/clausesel.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.79 2006/03/07 01:00:15 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/clausesel.c,v 1.80 2006/07/01 18:38:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -117,10 +117,18 @@ clauselist_selectivity(PlannerInfo *root,
/*
* Check for being passed a RestrictInfo.
*
* If it's a pseudoconstant RestrictInfo, then s2 is either 1.0 or
* 0.0; just use that rather than looking for range pairs.
*/
if (IsA(clause, RestrictInfo))
{
rinfo = (RestrictInfo *) clause;
if (rinfo->pseudoconstant)
{
s1 = s1 * s2;
continue;
}
clause = (Node *) rinfo->clause;
}
else
@ -422,6 +430,20 @@ clause_selectivity(PlannerInfo *root,
{
rinfo = (RestrictInfo *) clause;
/*
* If the clause is marked pseudoconstant, then it will be used as
* a gating qual and should not affect selectivity estimates; hence
* return 1.0. The only exception is that a constant FALSE may
* be taken as having selectivity 0.0, since it will surely mean
* no rows out of the plan. This case is simple enough that we
* need not bother caching the result.
*/
if (rinfo->pseudoconstant)
{
if (! IsA(rinfo->clause, Const))
return s1;
}
/*
* If possible, cache the result of the selectivity calculation for
* the clause. We can cache if varRelid is zero or the clause
@ -509,7 +531,10 @@ clause_selectivity(PlannerInfo *root,
else if (IsA(clause, Const))
{
/* bool constant is pretty easy... */
s1 = ((bool) ((Const *) clause)->constvalue) ? 1.0 : 0.0;
Const *con = (Const *) clause;
s1 = con->constisnull ? 0.0 :
DatumGetBool(con->constvalue) ? 1.0 : 0.0;
}
else if (IsA(clause, Param))
{
@ -519,7 +544,10 @@ clause_selectivity(PlannerInfo *root,
if (IsA(subst, Const))
{
/* bool constant is pretty easy... */
s1 = ((bool) ((Const *) subst)->constvalue) ? 1.0 : 0.0;
Const *con = (Const *) subst;
s1 = con->constisnull ? 0.0 :
DatumGetBool(con->constvalue) ? 1.0 : 0.0;
}
else
{

31
src/backend/optimizer/path/costsize.c
View File

@ -54,7 +54,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.158 2006/06/06 17:59:57 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/costsize.c,v 1.159 2006/07/01 18:38:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -1604,20 +1604,29 @@ cost_qual_eval(QualCost *cost, List *quals)
* routine's use, so that it's not necessary to evaluate the qual
* clause's cost more than once. If the clause's cost hasn't been
* computed yet, the field's startup value will contain -1.
*
* If the RestrictInfo is marked pseudoconstant, it will be tested
* only once, so treat its cost as all startup cost.
*/
if (qual && IsA(qual, RestrictInfo))
{
RestrictInfo *restrictinfo = (RestrictInfo *) qual;
RestrictInfo *rinfo = (RestrictInfo *) qual;
if (restrictinfo->eval_cost.startup < 0)
if (rinfo->eval_cost.startup < 0)
{
restrictinfo->eval_cost.startup = 0;
restrictinfo->eval_cost.per_tuple = 0;
cost_qual_eval_walker((Node *) restrictinfo->clause,
&restrictinfo->eval_cost);
rinfo->eval_cost.startup = 0;
rinfo->eval_cost.per_tuple = 0;
cost_qual_eval_walker((Node *) rinfo->clause,
&rinfo->eval_cost);
if (rinfo->pseudoconstant)
{
/* count one execution during startup */
rinfo->eval_cost.startup += rinfo->eval_cost.per_tuple;
rinfo->eval_cost.per_tuple = 0;
}
cost->startup += restrictinfo->eval_cost.startup;
cost->per_tuple += restrictinfo->eval_cost.per_tuple;
}
cost->startup += rinfo->eval_cost.startup;
cost->per_tuple += rinfo->eval_cost.per_tuple;
}
else
{
@ -1876,7 +1885,9 @@ set_joinrel_size_estimates(PlannerInfo *root, RelOptInfo *rel,
*
* If we are doing an outer join, take that into account: the output must
* be at least as large as the non-nullable input. (Is there any chance
* of being even smarter?)
* of being even smarter?) (XXX this is not really right, because it
* assumes all the restriction clauses are join clauses; we should figure
* pushed-down clauses separately.)
*
* For JOIN_IN and variants, the Cartesian product is figured with respect
* to a unique-ified input, and then we can clamp to the size of the other

28
src/backend/optimizer/path/indxpath.c
View File

@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.208 2006/06/07 17:08:07 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/path/indxpath.c,v 1.209 2006/07/01 18:38:32 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -998,6 +998,15 @@ match_clause_to_indexcol(IndexOptInfo *index,
Oid expr_op;
bool plain_op;
/*
* Never match pseudoconstants to indexes. (Normally this could not
* happen anyway, since a pseudoconstant clause couldn't contain a
* Var, but what if someone builds an expression index on a constant?
* It's not totally unreasonable to do so with a partial index, either.)
*/
if (rinfo->pseudoconstant)
return false;
/* First check for boolean-index cases. */
if (IsBooleanOpclass(opclass))
{
@ -2212,6 +2221,7 @@ expand_indexqual_conditions(IndexOptInfo *index, List *clausegroups)
make_restrictinfo(boolqual,
true,
false,
false,
NULL));
continue;
}
@ -2577,7 +2587,7 @@ expand_indexqual_rowcompare(RestrictInfo *rinfo,
matching_cols);
rc->rargs = list_truncate((List *) copyObject(clause->rargs),
matching_cols);
return make_restrictinfo((Expr *) rc, true, false, NULL);
return make_restrictinfo((Expr *) rc, true, false, false, NULL);
}
else
{
@ -2586,7 +2596,7 @@ expand_indexqual_rowcompare(RestrictInfo *rinfo,
opexpr = make_opclause(linitial_oid(new_ops), BOOLOID, false,
copyObject(linitial(clause->largs)),
copyObject(linitial(clause->rargs)));
return make_restrictinfo(opexpr, true, false, NULL);
return make_restrictinfo(opexpr, true, false, false, NULL);
}
}
@ -2678,7 +2688,7 @@ prefix_quals(Node *leftop, Oid opclass,
elog(ERROR, "no = operator for opclass %u", opclass);
expr = make_opclause(oproid, BOOLOID, false,
(Expr *) leftop, (Expr *) prefix_const);
result = list_make1(make_restrictinfo(expr, true, false, NULL));
result = list_make1(make_restrictinfo(expr, true, false, false, NULL));
return result;
}
@ -2693,7 +2703,7 @@ prefix_quals(Node *leftop, Oid opclass,
elog(ERROR, "no >= operator for opclass %u", opclass);
expr = make_opclause(oproid, BOOLOID, false,
(Expr *) leftop, (Expr *) prefix_const);
result = list_make1(make_restrictinfo(expr, true, false, NULL));
result = list_make1(make_restrictinfo(expr, true, false, false, NULL));
/*-------
* If we can create a string larger than the prefix, we can say
@ -2709,7 +2719,8 @@ prefix_quals(Node *leftop, Oid opclass,
elog(ERROR, "no < operator for opclass %u", opclass);
expr = make_opclause(oproid, BOOLOID, false,
(Expr *) leftop, (Expr *) greaterstr);
result = lappend(result, make_restrictinfo(expr, true, false, NULL));
result = lappend(result,
make_restrictinfo(expr, true, false, false, NULL));
}
return result;
@ -2772,7 +2783,7 @@ network_prefix_quals(Node *leftop, Oid expr_op, Oid opclass, Datum rightop)
(Expr *) leftop,
(Expr *) makeConst(datatype, -1, opr1right,
false, false));
result = list_make1(make_restrictinfo(expr, true, false, NULL));
result = list_make1(make_restrictinfo(expr, true, false, false, NULL));
/* create clause "key <= network_scan_last( rightop )" */
@ -2787,7 +2798,8 @@ network_prefix_quals(Node *leftop, Oid expr_op, Oid opclass, Datum rightop)
(Expr *) leftop,
(Expr *) makeConst(datatype, -1, opr2right,
false, false));
result = lappend(result, make_restrictinfo(expr, true, false, NULL));
result = lappend(result,
make_restrictinfo(expr, true, false, false, NULL));
return result;
}

188
src/backend/optimizer/plan/createplan.c
View File

@ -10,7 +10,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.211 2006/05/18 18:57:31 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/createplan.c,v 1.212 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -35,11 +35,12 @@
#include "utils/syscache.h"
static Scan *create_scan_plan(PlannerInfo *root, Path *best_path);
static Plan *create_scan_plan(PlannerInfo *root, Path *best_path);
static List *build_relation_tlist(RelOptInfo *rel);
static bool use_physical_tlist(RelOptInfo *rel);
static void disuse_physical_tlist(Plan *plan, Path *path);
static Join *create_join_plan(PlannerInfo *root, JoinPath *best_path);
static Plan *create_gating_plan(PlannerInfo *root, Plan *plan, List *quals);
static Plan *create_join_plan(PlannerInfo *root, JoinPath *best_path);
static Plan *create_append_plan(PlannerInfo *root, AppendPath *best_path);
static Result *create_result_plan(PlannerInfo *root, ResultPath *best_path);
static Material *create_material_plan(PlannerInfo *root, MaterialPath *best_path);
@ -74,6 +75,7 @@ static void fix_indexqual_references(List *indexquals, IndexPath *index_path,
static Node *fix_indexqual_operand(Node *node, IndexOptInfo *index,
Oid *opclass);
static List *get_switched_clauses(List *clauses, Relids outerrelids);
static List *order_qual_clauses(PlannerInfo *root, List *clauses);
static void copy_path_costsize(Plan *dest, Path *src);
static void copy_plan_costsize(Plan *dest, Plan *src);
static SeqScan *make_seqscan(List *qptlist, List *qpqual, Index scanrelid);
@ -146,16 +148,16 @@ create_plan(PlannerInfo *root, Path *best_path)
case T_TidScan:
case T_SubqueryScan:
case T_FunctionScan:
plan = (Plan *) create_scan_plan(root, best_path);
plan = create_scan_plan(root, best_path);
break;
case T_HashJoin:
case T_MergeJoin:
case T_NestLoop:
plan = (Plan *) create_join_plan(root,
plan = create_join_plan(root,
(JoinPath *) best_path);
break;
case T_Append:
plan = (Plan *) create_append_plan(root,
plan = create_append_plan(root,
(AppendPath *) best_path);
break;
case T_Result:
@ -167,7 +169,7 @@ create_plan(PlannerInfo *root, Path *best_path)
(MaterialPath *) best_path);
break;
case T_Unique:
plan = (Plan *) create_unique_plan(root,
plan = create_unique_plan(root,
(UniquePath *) best_path);
break;
default:
@ -183,16 +185,14 @@ create_plan(PlannerInfo *root, Path *best_path)
/*
* create_scan_plan
* Create a scan plan for the parent relation of 'best_path'.
*
* Returns a Plan node.
*/
static Scan *
static Plan *
create_scan_plan(PlannerInfo *root, Path *best_path)
{
RelOptInfo *rel = best_path->parent;
List *tlist;
List *scan_clauses;
Scan *plan;
Plan *plan;
/*
* For table scans, rather than using the relation targetlist (which is
@ -213,22 +213,23 @@ create_scan_plan(PlannerInfo *root, Path *best_path)
tlist = build_relation_tlist(rel);
/*
* Extract the relevant restriction clauses from the parent relation; the
* executor must apply all these restrictions during the scan.
* Extract the relevant restriction clauses from the parent relation.
* The executor must apply all these restrictions during the scan,
* except for pseudoconstants which we'll take care of below.
*/
scan_clauses = rel->baserestrictinfo;
switch (best_path->pathtype)
{
case T_SeqScan:
plan = (Scan *) create_seqscan_plan(root,
plan = (Plan *) create_seqscan_plan(root,
best_path,
tlist,
scan_clauses);
break;
case T_IndexScan:
plan = (Scan *) create_indexscan_plan(root,
plan = (Plan *) create_indexscan_plan(root,
(IndexPath *) best_path,
tlist,
scan_clauses,
@ -236,28 +237,28 @@ create_scan_plan(PlannerInfo *root, Path *best_path)
break;
case T_BitmapHeapScan:
plan = (Scan *) create_bitmap_scan_plan(root,
plan = (Plan *) create_bitmap_scan_plan(root,
(BitmapHeapPath *) best_path,
tlist,
scan_clauses);
break;
case T_TidScan:
plan = (Scan *) create_tidscan_plan(root,
plan = (Plan *) create_tidscan_plan(root,
(TidPath *) best_path,
tlist,
scan_clauses);
break;
case T_SubqueryScan:
plan = (Scan *) create_subqueryscan_plan(root,
plan = (Plan *) create_subqueryscan_plan(root,
best_path,
tlist,
scan_clauses);
break;
case T_FunctionScan:
plan = (Scan *) create_functionscan_plan(root,
plan = (Plan *) create_functionscan_plan(root,
best_path,
tlist,
scan_clauses);
@ -270,6 +271,14 @@ create_scan_plan(PlannerInfo *root, Path *best_path)
break;
}
/*
* If there are any pseudoconstant clauses attached to this node,
* insert a gating Result node that evaluates the pseudoconstants
* as one-time quals.
*/
if (root->hasPseudoConstantQuals)
plan = create_gating_plan(root, plan, scan_clauses);
return plan;
}
@ -365,19 +374,54 @@ disuse_physical_tlist(Plan *plan, Path *path)
}
}
/*
* create_gating_plan
* Deal with pseudoconstant qual clauses
*
* If the node's quals list includes any pseudoconstant quals, put them
* into a gating Result node atop the already-built plan. Otherwise,
* return the plan as-is.
*
* Note that we don't change cost or size estimates when doing gating.
* The costs of qual eval were already folded into the plan's startup cost.
* Leaving the size alone amounts to assuming that the gating qual will
* succeed, which is the conservative estimate for planning upper queries.
* We certainly don't want to assume the output size is zero (unless the
* gating qual is actually constant FALSE, and that case is dealt with in
* clausesel.c). Interpolating between the two cases is silly, because
* it doesn't reflect what will really happen at runtime, and besides which
* in most cases we have only a very bad idea of the probability of the gating
* qual being true.
*/
static Plan *
create_gating_plan(PlannerInfo *root, Plan *plan, List *quals)
{
List *pseudoconstants;
/* Pull out any pseudoconstant quals from the RestrictInfo list */
pseudoconstants = extract_actual_clauses(quals, true);
if (!pseudoconstants)
return plan;
pseudoconstants = order_qual_clauses(root, pseudoconstants);
return (Plan *) make_result((List *) copyObject(plan->targetlist),
(Node *) pseudoconstants,
plan);
}
/*
* create_join_plan
* Create a join plan for 'best_path' and (recursively) plans for its
* inner and outer paths.
*
* Returns a Plan node.
*/
static Join *
static Plan *
create_join_plan(PlannerInfo *root, JoinPath *best_path)
{
Plan *outer_plan;
Plan *inner_plan;
Join *plan;
Plan *plan;
outer_plan = create_plan(root, best_path->outerjoinpath);
inner_plan = create_plan(root, best_path->innerjoinpath);
@ -385,19 +429,19 @@ create_join_plan(PlannerInfo *root, JoinPath *best_path)
switch (best_path->path.pathtype)
{
case T_MergeJoin:
plan = (Join *) create_mergejoin_plan(root,
plan = (Plan *) create_mergejoin_plan(root,
(MergePath *) best_path,
outer_plan,
inner_plan);
break;
case T_HashJoin:
plan = (Join *) create_hashjoin_plan(root,
plan = (Plan *) create_hashjoin_plan(root,
(HashPath *) best_path,
outer_plan,
inner_plan);
break;
case T_NestLoop:
plan = (Join *) create_nestloop_plan(root,
plan = (Plan *) create_nestloop_plan(root,
(NestPath *) best_path,
outer_plan,
inner_plan);
@ -409,6 +453,14 @@ create_join_plan(PlannerInfo *root, JoinPath *best_path)
break;
}
/*
* If there are any pseudoconstant clauses attached to this node,
* insert a gating Result node that evaluates the pseudoconstants
* as one-time quals.
*/
if (root->hasPseudoConstantQuals)
plan = create_gating_plan(root, plan, best_path->joinrestrictinfo);
#ifdef NOT_USED
/*
@ -473,34 +525,24 @@ create_append_plan(PlannerInfo *root, AppendPath *best_path)
/*
* create_result_plan
* Create a Result plan for 'best_path' and (recursively) plans
* for its subpaths.
* Create a Result plan for 'best_path'.
* This is only used for the case of a query with an empty jointree.
*
* Returns a Plan node.
*/
static Result *
create_result_plan(PlannerInfo *root, ResultPath *best_path)
{
Result *plan;
List *tlist;
List *constclauses;
Plan *subplan;
List *quals;
if (best_path->path.parent)
tlist = build_relation_tlist(best_path->path.parent);
else
tlist = NIL; /* will be filled in later */
/* The tlist will be installed later, since we have no RelOptInfo */
Assert(best_path->path.parent == NULL);
tlist = NIL;
if (best_path->subpath)
subplan = create_plan(root, best_path->subpath);
else
subplan = NULL;
quals = order_qual_clauses(root, best_path->quals);
constclauses = order_qual_clauses(root, best_path->constantqual);
plan = make_result(tlist, (Node *) constclauses, subplan);
return plan;
return make_result(tlist, (Node *) quals, NULL);
}
/*
@ -716,8 +758,8 @@ create_seqscan_plan(PlannerInfo *root, Path *best_path,
Assert(scan_relid > 0);
Assert(best_path->parent->rtekind == RTE_RELATION);
/* Reduce RestrictInfo list to bare expressions */
scan_clauses = get_actual_clauses(scan_clauses);
/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
scan_clauses = extract_actual_clauses(scan_clauses, false);
/* Sort clauses into best execution order */
scan_clauses = order_qual_clauses(root, scan_clauses);
@ -824,7 +866,8 @@ create_indexscan_plan(PlannerInfo *root,
* plan so that they'll be properly rechecked by EvalPlanQual testing.
*
* While at it, we strip off the RestrictInfos to produce a list of plain
* expressions.
* expressions (this loop replaces extract_actual_clauses used in the
* other routines in this file). We have to ignore pseudoconstants.
*/
qpqual = NIL;
foreach(l, scan_clauses)
@ -832,6 +875,8 @@ create_indexscan_plan(PlannerInfo *root,
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
Assert(IsA(rinfo, RestrictInfo));
if (rinfo->pseudoconstant)
continue;
if (list_member_ptr(nonlossy_indexquals, rinfo))
continue;
if (!contain_mutable_functions((Node *) rinfo->clause))
@ -900,8 +945,8 @@ create_bitmap_scan_plan(PlannerInfo *root,
bitmapqualplan = create_bitmap_subplan(root, best_path->bitmapqual,
&bitmapqualorig, &indexquals);
/* Reduce RestrictInfo list to bare expressions */
scan_clauses = get_actual_clauses(scan_clauses);
/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
scan_clauses = extract_actual_clauses(scan_clauses, false);
/*
* If this is a innerjoin scan, the indexclauses will contain join clauses
@ -1183,8 +1228,8 @@ create_tidscan_plan(PlannerInfo *root, TidPath *best_path,
Assert(scan_relid > 0);
Assert(best_path->path.parent->rtekind == RTE_RELATION);
/* Reduce RestrictInfo list to bare expressions */
scan_clauses = get_actual_clauses(scan_clauses);
/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
scan_clauses = extract_actual_clauses(scan_clauses, false);
/*
* Remove any clauses that are TID quals. This is a bit tricky since
@ -1224,8 +1269,8 @@ create_subqueryscan_plan(PlannerInfo *root, Path *best_path,
Assert(scan_relid > 0);
Assert(best_path->parent->rtekind == RTE_SUBQUERY);
/* Reduce RestrictInfo list to bare expressions */
scan_clauses = get_actual_clauses(scan_clauses);
/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
scan_clauses = extract_actual_clauses(scan_clauses, false);
/* Sort clauses into best execution order */
scan_clauses = order_qual_clauses(root, scan_clauses);
@ -1256,8 +1301,8 @@ create_functionscan_plan(PlannerInfo *root, Path *best_path,
Assert(scan_relid > 0);
Assert(best_path->parent->rtekind == RTE_FUNCTION);
/* Reduce RestrictInfo list to bare expressions */
scan_clauses = get_actual_clauses(scan_clauses);
/* Reduce RestrictInfo list to bare expressions; ignore pseudoconstants */
scan_clauses = extract_actual_clauses(scan_clauses, false);
/* Sort clauses into best execution order */
scan_clauses = order_qual_clauses(root, scan_clauses);
@ -1348,15 +1393,16 @@ create_nestloop_plan(PlannerInfo *root,
}
/* Get the join qual clauses (in plain expression form) */
/* Any pseudoconstant clauses are ignored here */
if (IS_OUTER_JOIN(best_path->jointype))
{
get_actual_join_clauses(joinrestrictclauses,
extract_actual_join_clauses(joinrestrictclauses,
&joinclauses, &otherclauses);
}
else
{
/* We can treat all clauses alike for an inner join */
joinclauses = get_actual_clauses(joinrestrictclauses);
joinclauses = extract_actual_clauses(joinrestrictclauses, false);
otherclauses = NIL;
}
@ -1389,15 +1435,17 @@ create_mergejoin_plan(PlannerInfo *root,
MergeJoin *join_plan;
/* Get the join qual clauses (in plain expression form) */
/* Any pseudoconstant clauses are ignored here */
if (IS_OUTER_JOIN(best_path->jpath.jointype))
{
get_actual_join_clauses(best_path->jpath.joinrestrictinfo,
extract_actual_join_clauses(best_path->jpath.joinrestrictinfo,
&joinclauses, &otherclauses);
}
else
{
/* We can treat all clauses alike for an inner join */
joinclauses = get_actual_clauses(best_path->jpath.joinrestrictinfo);
joinclauses = extract_actual_clauses(best_path->jpath.joinrestrictinfo,
false);
otherclauses = NIL;
}
@ -1473,15 +1521,17 @@ create_hashjoin_plan(PlannerInfo *root,
Hash *hash_plan;
/* Get the join qual clauses (in plain expression form) */
/* Any pseudoconstant clauses are ignored here */
if (IS_OUTER_JOIN(best_path->jpath.jointype))
{
get_actual_join_clauses(best_path->jpath.joinrestrictinfo,
extract_actual_join_clauses(best_path->jpath.joinrestrictinfo,
&joinclauses, &otherclauses);
}
else
{
/* We can treat all clauses alike for an inner join */
joinclauses = get_actual_clauses(best_path->jpath.joinrestrictinfo);
joinclauses = extract_actual_clauses(best_path->jpath.joinrestrictinfo,
false);
otherclauses = NIL;
}
@ -1831,7 +1881,7 @@ get_switched_clauses(List *clauses, Relids outerrelids)
* For now, we just move any quals that contain SubPlan references (but not
* InitPlan references) to the end of the list.
*/
List *
static List *
order_qual_clauses(PlannerInfo *root, List *clauses)
{
List *nosubplans;
@ -2880,6 +2930,15 @@ make_limit(Plan *lefttree, Node *limitOffset, Node *limitCount,
return node;
}
/*
* make_result
* Build a Result plan node
*
* If we have a subplan, assume that any evaluation costs for the gating qual
* were already factored into the subplan's startup cost, and just copy the
* subplan cost. If there's no subplan, we should include the qual eval
* cost. In either case, tlist eval cost is not to be included here.
*/
Result *
make_result(List *tlist,
Node *resconstantqual,
@ -2895,9 +2954,7 @@ make_result(List *tlist,
plan->startup_cost = 0;
plan->total_cost = cpu_tuple_cost;
plan->plan_rows = 1; /* wrong if we have a set-valued function? */
plan->plan_width = 0; /* XXX try to be smarter? */
}
plan->plan_width = 0; /* XXX is it worth being smarter? */
if (resconstantqual)
{
QualCost qual_cost;
@ -2907,6 +2964,7 @@ make_result(List *tlist,
plan->startup_cost += qual_cost.startup + qual_cost.per_tuple;
plan->total_cost += qual_cost.startup + qual_cost.per_tuple;
}
}
plan->targetlist = tlist;
plan->qual = NIL;

71
src/backend/optimizer/plan/initsplan.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.117 2006/03/14 22:48:19 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/initsplan.c,v 1.118 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -23,6 +23,7 @@
#include "optimizer/pathnode.h"
#include "optimizer/paths.h"
#include "optimizer/planmain.h"
#include "optimizer/prep.h"
#include "optimizer/restrictinfo.h"
#include "optimizer/tlist.h"
#include "optimizer/var.h"
@ -72,6 +73,9 @@ static void check_hashjoinable(RestrictInfo *restrictinfo);
* the base relations (ie, table, subquery, and function RTEs)
* appearing in the jointree.
*
* The initial invocation must pass root->parse->jointree as the value of
* jtnode. Internally, the function recurses through the jointree.
*
* At the end of this process, there should be one baserel RelOptInfo for
* every non-join RTE that is used in the query. Therefore, this routine
* is the only place that should call build_simple_rel with reloptkind
@ -578,6 +582,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
{
Relids relids;
bool outerjoin_delayed;
bool pseudoconstant = false;
bool maybe_equijoin;
bool maybe_outer_join;
RestrictInfo *restrictinfo;
@ -599,16 +604,57 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
elog(ERROR, "JOIN qualification may not refer to other relations");
/*
* If the clause is variable-free, we force it to be evaluated at its
* original syntactic level. Note that this should not happen for
* top-level clauses, because query_planner() special-cases them. But it
* will happen for variable-free JOIN/ON clauses. We don't have to be
* real smart about such a case, we just have to be correct. Also note
* that for an outer-join clause, we must force it to the OJ's semantic
* level, not the syntactic scope.
* If the clause is variable-free, our normal heuristic for pushing it
* down to just the mentioned rels doesn't work, because there are none.
*
* If the clause is an outer-join clause, we must force it to the OJ's
* semantic level to preserve semantics.
*
* Otherwise, when the clause contains volatile functions, we force it
* to be evaluated at its original syntactic level. This preserves the
* expected semantics.
*
* When the clause contains no volatile functions either, it is actually
* a pseudoconstant clause that will not change value during any one
* execution of the plan, and hence can be used as a one-time qual in
* a gating Result plan node. We put such a clause into the regular
* RestrictInfo lists for the moment, but eventually createplan.c will
* pull it out and make a gating Result node immediately above whatever
* plan node the pseudoconstant clause is assigned to. It's usually
* best to put a gating node as high in the plan tree as possible.
* If we are not below an outer join, we can actually push the
* pseudoconstant qual all the way to the top of the tree. If we are
* below an outer join, we leave the qual at its original syntactic level
* (we could push it up to just below the outer join, but that seems more
* complex than it's worth).
*/
if (bms_is_empty(relids))
relids = ojscope ? ojscope : qualscope;
{
if (ojscope)
{
/* clause is attached to outer join, eval it there */
relids = ojscope;
/* mustn't use as gating qual, so don't mark pseudoconstant */
}
else
{
/* eval at original syntactic level */
relids = qualscope;
if (!contain_volatile_functions(clause))
{
/* mark as gating qual */
pseudoconstant = true;
/* tell createplan.c to check for gating quals */
root->hasPseudoConstantQuals = true;
/* if not below outer join, push it to top of tree */
if (!below_outer_join)
{
relids = get_relids_in_jointree((Node *) root->parse->jointree);
is_pushed_down = true;
}
}
}
}
/*
* Check to see if clause application must be delayed by outer-join
@ -624,6 +670,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
*/
Assert(bms_equal(relids, qualscope));
Assert(!ojscope);
Assert(!pseudoconstant);
/* Needn't feed it back for more deductions */
outerjoin_delayed = false;
maybe_equijoin = false;
@ -647,6 +694,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
Assert(ojscope);
relids = ojscope;
outerjoin_delayed = true;
Assert(!pseudoconstant);
/*
* We can't use such a clause to deduce equijoin (the left and right
@ -738,6 +786,7 @@ distribute_qual_to_rels(PlannerInfo *root, Node *clause,
restrictinfo = make_restrictinfo((Expr *) clause,
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
relids);
/*
@ -1179,6 +1228,8 @@ check_mergejoinable(RestrictInfo *restrictinfo)
leftOp,
rightOp;
if (restrictinfo->pseudoconstant)
return;
if (!is_opclause(clause))
return;
if (list_length(((OpExpr *) clause)->args) != 2)
@ -1212,6 +1263,8 @@ check_hashjoinable(RestrictInfo *restrictinfo)
Expr *clause = restrictinfo->clause;
Oid opno;
if (restrictinfo->pseudoconstant)
return;
if (!is_opclause(clause))
return;
if (list_length(((OpExpr *) clause)->args) != 2)

47
src/backend/optimizer/plan/planagg.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planagg.c,v 1.15 2006/06/06 17:59:57 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planagg.c,v 1.16 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -46,8 +46,7 @@ static bool build_minmax_path(PlannerInfo *root, RelOptInfo *rel,
MinMaxAggInfo *info);
static ScanDirection match_agg_to_index_col(MinMaxAggInfo *info,
IndexOptInfo *index, int indexcol);
static void make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info,
List *constant_quals);
static void make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info);
static Node *replace_aggs_with_params_mutator(Node *node, List **context);
static Oid fetch_agg_sort_op(Oid aggfnoid);
@ -81,7 +80,6 @@ optimize_minmax_aggregates(PlannerInfo *root, List *tlist, Path *best_path)
Plan *plan;
Node *hqual;
QualCost tlist_cost;
List *constant_quals;
/* Nothing to do if query has no aggregates */
if (!parse->hasAggs)
@ -164,27 +162,13 @@ optimize_minmax_aggregates(PlannerInfo *root, List *tlist, Path *best_path)
return NULL; /* too expensive */
/*
* OK, we are going to generate an optimized plan. The first thing we
* need to do is look for any non-variable WHERE clauses that
* query_planner might have removed from the basic plan. (Normal WHERE
* clauses will be properly incorporated into the sub-plans by
* create_plan.) If there are any, they will be in a gating Result node
* atop the best_path. They have to be incorporated into a gating Result
* in each sub-plan in order to produce the semantically correct result.
* OK, we are going to generate an optimized plan.
*/
if (IsA(best_path, ResultPath))
{
constant_quals = ((ResultPath *) best_path)->constantqual;
/* no need to do this more than once: */
constant_quals = order_qual_clauses(root, constant_quals);
}
else
constant_quals = NIL;
/* Pass 3: generate subplans and output Param nodes */
foreach(l, aggs_list)
{
make_agg_subplan(root, (MinMaxAggInfo *) lfirst(l), constant_quals);
make_agg_subplan(root, (MinMaxAggInfo *) lfirst(l));
}
/*
@ -434,11 +418,12 @@ match_agg_to_index_col(MinMaxAggInfo *info, IndexOptInfo *index, int indexcol)
* Construct a suitable plan for a converted aggregate query
*/
static void
make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info, List *constant_quals)
make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info)
{
PlannerInfo subroot;
Query *subparse;
Plan *plan;
Plan *iplan;
TargetEntry *tle;
SortClause *sortcl;
NullTest *ntest;
@ -482,8 +467,7 @@ make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info, List *constant_quals)
/*
* Generate the plan for the subquery. We already have a Path for the
* basic indexscan, but we have to convert it to a Plan and attach a LIMIT
* node above it. We might need a gating Result, too, to handle any
* non-variable qual clauses.
* node above it.
*
* Also we must add a "WHERE foo IS NOT NULL" restriction to the
* indexscan, to be sure we don't return a NULL, which'd be contrary to
@ -491,21 +475,26 @@ make_agg_subplan(PlannerInfo *root, MinMaxAggInfo *info, List *constant_quals)
* earlier, so that the selectivity of the restriction could be included
* in our cost estimates. But that looks painful, and in most cases the
* fraction of NULLs isn't high enough to change the decision.
*
* The NOT NULL qual has to go on the actual indexscan; create_plan
* might have stuck a gating Result atop that, if there were any
* pseudoconstant quals.
*/
plan = create_plan(&subroot, (Path *) info->path);
plan->targetlist = copyObject(subparse->targetList);
if (IsA(plan, Result))
iplan = plan->lefttree;
else
iplan = plan;
Assert(IsA(iplan, IndexScan));
ntest = makeNode(NullTest);
ntest->nulltesttype = IS_NOT_NULL;
ntest->arg = copyObject(info->target);
plan->qual = lcons(ntest, plan->qual);
if (constant_quals)
plan = (Plan *) make_result(copyObject(plan->targetlist),
copyObject(constant_quals),
plan);
iplan->qual = lcons(ntest, iplan->qual);
plan = (Plan *) make_limit(plan,
subparse->limitOffset,

35
src/backend/optimizer/plan/planmain.c
View File

@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.93 2006/03/05 15:58:29 momjian Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planmain.c,v 1.94 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -82,7 +82,6 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction,
double *num_groups)
{
Query *parse = root->parse;
List *constant_quals;
List *joinlist;
RelOptInfo *final_rel;
Path *cheapestpath;
@ -99,26 +98,12 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction,
*/
if (parse->jointree->fromlist == NIL)
{
*cheapest_path = (Path *) create_result_path(NULL, NULL,
(List *) parse->jointree->quals);
*cheapest_path = (Path *)
create_result_path((List *) parse->jointree->quals);
*sorted_path = NULL;
return;
}
/*
* Pull out any non-variable WHERE clauses so these can be put in a
* toplevel "Result" node, where they will gate execution of the whole
* plan (the Result will not invoke its descendant plan unless the quals
* are true). Note that any *really* non-variable quals will have been
* optimized away by eval_const_expressions(). What we're mostly
* interested in here is quals that depend only on outer-level vars,
* although if the qual reduces to "WHERE FALSE" this path will also be
* taken.
*/
parse->jointree->quals = (Node *)
pull_constant_clauses((List *) parse->jointree->quals,
&constant_quals);
/*
* Init planner lists to empty, and set up the array to hold RelOptInfos
* for "simple" rels.
@ -324,20 +309,6 @@ query_planner(PlannerInfo *root, List *tlist, double tuple_fraction,
}
}
/*
* If we have constant quals, add a toplevel Result step to process them.
*/
if (constant_quals)
{
cheapestpath = (Path *) create_result_path(final_rel,
cheapestpath,
constant_quals);
if (sortedpath)
sortedpath = (Path *) create_result_path(final_rel,
sortedpath,
constant_quals);
}
*cheapest_path = cheapestpath;
*sorted_path = sortedpath;
}

5
src/backend/optimizer/plan/planner.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.200 2006/06/28 20:04:38 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/plan/planner.c,v 1.201 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -270,6 +270,9 @@ subquery_planner(Query *parse, double tuple_fraction,
*/
root->hasHavingQual = (parse->havingQual != NULL);
/* Clear this flag; might get set in distribute_qual_to_rels */
root->hasPseudoConstantQuals = false;
/*
* Do expression preprocessing on targetlist and quals.
*/

43
src/backend/optimizer/util/clauses.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.212 2006/06/16 18:42:22 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.213 2006/07/01 18:38:33 tgl Exp $
*
* HISTORY
* AUTHOR DATE MAJOR EVENT
@ -1052,14 +1052,13 @@ is_strict_saop(ScalarArrayOpExpr *expr, bool falseOK)
/*
* is_pseudo_constant_clause
* Detect whether a clause is "constant", ie, it contains no variables
* of the current query level and no uses of volatile functions.
* Such a clause is not necessarily a true constant: it can still contain
* Detect whether an expression is "pseudo constant", ie, it contains no
* variables of the current query level and no uses of volatile functions.
* Such an expr is not necessarily a true constant: it can still contain
* Params and outer-level Vars, not to mention functions whose results
* may vary from one statement to the next. However, the clause's value
* may vary from one statement to the next. However, the expr's value
* will be constant over any one scan of the current query, so it can be
* used as an indexscan key or (if a top-level qual) can be pushed up to
* become a gating qual.
* used as, eg, an indexscan key.
*/
bool
is_pseudo_constant_clause(Node *clause)
@ -1079,7 +1078,7 @@ is_pseudo_constant_clause(Node *clause)
/*
* is_pseudo_constant_clause_relids
* Same as above, except caller already has available the var membership
* of the clause; this lets us avoid the contain_var_clause() scan.
* of the expression; this lets us avoid the contain_var_clause() scan.
*/
bool
is_pseudo_constant_clause_relids(Node *clause, Relids relids)
@ -1090,34 +1089,6 @@ is_pseudo_constant_clause_relids(Node *clause, Relids relids)
return false;
}
/*
* pull_constant_clauses
* Scan through a list of qualifications and separate "constant" quals
* from those that are not.
*
* Returns a list of the pseudo-constant clauses in constantQual and the
* remaining quals as the return value.
*/
List *
pull_constant_clauses(List *quals, List **constantQual)
{
List *constqual = NIL,
*restqual = NIL;
ListCell *q;
foreach(q, quals)
{
Node *qual = (Node *) lfirst(q);
if (is_pseudo_constant_clause(qual))
constqual = lappend(constqual, qual);
else
restqual = lappend(restqual, qual);
}
*constantQual = constqual;
return restqual;
}
/*****************************************************************************
* Tests on clauses of queries

33
src/backend/optimizer/util/pathnode.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/pathnode.c,v 1.128 2006/06/06 17:59:57 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/pathnode.c,v 1.129 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -667,36 +667,29 @@ create_append_path(RelOptInfo *rel, List *subpaths)
/*
* create_result_path
* Creates a path corresponding to a Result plan, returning the
* pathnode.
* Creates a path representing a Result-and-nothing-else plan.
* This is only used for the case of a query with an empty jointree.
*/
ResultPath *
create_result_path(RelOptInfo *rel, Path *subpath, List *constantqual)
create_result_path(List *quals)
{
ResultPath *pathnode = makeNode(ResultPath);
pathnode->path.pathtype = T_Result;
pathnode->path.parent = rel; /* may be NULL */
if (subpath)
pathnode->path.pathkeys = subpath->pathkeys;
else
pathnode->path.parent = NULL;
pathnode->path.pathkeys = NIL;
pathnode->subpath = subpath;
pathnode->constantqual = constantqual;
pathnode->quals = quals;
/* Ideally should define cost_result(), but I'm too lazy */
if (subpath)
{
pathnode->path.startup_cost = subpath->startup_cost;
pathnode->path.total_cost = subpath->total_cost;
}
else
{
pathnode->path.startup_cost = 0;
pathnode->path.total_cost = cpu_tuple_cost;
}
/*
* In theory we should include the qual eval cost as well, but
* at present that doesn't accomplish much except duplicate work that
* will be done again in make_result; since this is only used for
* degenerate cases, nothing interesting will be done with the path
* cost values...
*/
return pathnode;
}

118
src/backend/optimizer/util/restrictinfo.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.47 2006/04/07 17:05:39 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.48 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -26,10 +26,12 @@ static RestrictInfo *make_restrictinfo_internal(Expr *clause,
Expr *orclause,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Relids required_relids);
static Expr *make_sub_restrictinfos(Expr *clause,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Relids required_relids);
static RestrictInfo *join_clause_is_redundant(PlannerInfo *root,
RestrictInfo *rinfo,
@ -42,9 +44,10 @@ static RestrictInfo *join_clause_is_redundant(PlannerInfo *root,
*
* Build a RestrictInfo node containing the given subexpression.
*
* The is_pushed_down and outerjoin_delayed flags must be supplied by the
* caller. required_relids can be NULL, in which case it defaults to the
* actual clause contents (i.e., clause_relids).
* The is_pushed_down, outerjoin_delayed, and pseudoconstant flags for the
* RestrictInfo must be supplied by the caller. required_relids can be NULL,
* in which case it defaults to the actual clause contents (i.e.,
* clause_relids).
*
* We initialize fields that depend only on the given subexpression, leaving
* others that depend on context (or may never be needed at all) to be filled
@ -54,6 +57,7 @@ RestrictInfo *
make_restrictinfo(Expr *clause,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Relids required_relids)
{
/*
@ -64,13 +68,17 @@ make_restrictinfo(Expr *clause,
return (RestrictInfo *) make_sub_restrictinfos(clause,
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
required_relids);
/* Shouldn't be an AND clause, else AND/OR flattening messed up */
Assert(!and_clause((Node *) clause));
return make_restrictinfo_internal(clause, NULL,
is_pushed_down, outerjoin_delayed,
return make_restrictinfo_internal(clause,
NULL,
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
required_relids);
}
@ -85,7 +93,8 @@ make_restrictinfo(Expr *clause,
* RestrictInfos.
*
* The caller must pass is_pushed_down, but we assume outerjoin_delayed
* is false (no such qual should ever get into a bitmapqual).
* and pseudoconstant are false (no such qual should ever get into a
* bitmapqual).
*
* If include_predicates is true, we add any partial index predicates to
* the explicit index quals. When this is not true, we return a condition
@ -214,6 +223,7 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
make_orclause(withris),
is_pushed_down,
false,
false,
NULL));
}
}
@ -239,6 +249,7 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
make_restrictinfo(pred,
is_pushed_down,
false,
false,
NULL));
}
}
@ -258,8 +269,11 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
* Common code for the main entry points and the recursive cases.
*/
static RestrictInfo *
make_restrictinfo_internal(Expr *clause, Expr *orclause,
bool is_pushed_down, bool outerjoin_delayed,
make_restrictinfo_internal(Expr *clause,
Expr *orclause,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Relids required_relids)
{
RestrictInfo *restrictinfo = makeNode(RestrictInfo);
@ -268,6 +282,7 @@ make_restrictinfo_internal(Expr *clause, Expr *orclause,
restrictinfo->orclause = orclause;
restrictinfo->is_pushed_down = is_pushed_down;
restrictinfo->outerjoin_delayed = outerjoin_delayed;
restrictinfo->pseudoconstant = pseudoconstant;
restrictinfo->can_join = false; /* may get set below */
/*
@ -292,7 +307,11 @@ make_restrictinfo_internal(Expr *clause, Expr *orclause,
!bms_is_empty(restrictinfo->right_relids) &&
!bms_overlap(restrictinfo->left_relids,
restrictinfo->right_relids))
{
restrictinfo->can_join = true;
/* pseudoconstant should certainly not be true */
Assert(!restrictinfo->pseudoconstant);
}
}
else
{
@ -346,13 +365,18 @@ make_restrictinfo_internal(Expr *clause, Expr *orclause,
* implicit-AND lists at top level of RestrictInfo lists. Only ORs and
* simple clauses are valid RestrictInfos.
*
* The same is_pushed_down, outerjoin_delayed, and pseudoconstant flag
* values can be applied to all RestrictInfo nodes in the result.
*
* The given required_relids are attached to our top-level output,
* but any OR-clause constituents are allowed to default to just the
* contained rels.
*/
static Expr *
make_sub_restrictinfos(Expr *clause,
bool is_pushed_down, bool outerjoin_delayed,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Relids required_relids)
{
if (or_clause((Node *) clause))
@ -365,11 +389,13 @@ make_sub_restrictinfos(Expr *clause,
make_sub_restrictinfos(lfirst(temp),
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
NULL));
return (Expr *) make_restrictinfo_internal(clause,
make_orclause(orlist),
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
required_relids);
}
else if (and_clause((Node *) clause))
@ -382,6 +408,7 @@ make_sub_restrictinfos(Expr *clause,
make_sub_restrictinfos(lfirst(temp),
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
required_relids));
return make_andclause(andlist);
}
@ -390,6 +417,7 @@ make_sub_restrictinfos(Expr *clause,
NULL,
is_pushed_down,
outerjoin_delayed,
pseudoconstant,
required_relids);
}
@ -411,47 +439,91 @@ restriction_is_or_clause(RestrictInfo *restrictinfo)
* get_actual_clauses
*
* Returns a list containing the bare clauses from 'restrictinfo_list'.
*
* This is only to be used in cases where none of the RestrictInfos can
* be pseudoconstant clauses (for instance, it's OK on indexqual lists).
*/
List *
get_actual_clauses(List *restrictinfo_list)
{
List *result = NIL;
ListCell *temp;
ListCell *l;
foreach(temp, restrictinfo_list)
foreach(l, restrictinfo_list)
{
RestrictInfo *rinfo = (RestrictInfo *) lfirst(temp);
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
Assert(IsA(rinfo, RestrictInfo));
Assert(!rinfo->pseudoconstant);
result = lappend(result, rinfo->clause);
}
return result;
}
/*
* get_actual_join_clauses
* extract_actual_clauses
*
* Extract clauses from 'restrictinfo_list', separating those that
* Extract bare clauses from 'restrictinfo_list', returning either the
* regular ones or the pseudoconstant ones per 'pseudoconstant'.
*/
List *
extract_actual_clauses(List *restrictinfo_list,
bool pseudoconstant)
{
List *result = NIL;
ListCell *l;
foreach(l, restrictinfo_list)
{
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
Assert(IsA(rinfo, RestrictInfo));
if (rinfo->pseudoconstant == pseudoconstant)
result = lappend(result, rinfo->clause);
}
return result;
}
/*
* extract_actual_join_clauses
*
* Extract bare clauses from 'restrictinfo_list', separating those that
* syntactically match the join level from those that were pushed down.
* Pseudoconstant clauses are excluded from the results.
*
* This is only used at outer joins, since for plain joins we don't care
* about pushed-down-ness.
*/
void
get_actual_join_clauses(List *restrictinfo_list,
List **joinquals, List **otherquals)
extract_actual_join_clauses(List *restrictinfo_list,
List **joinquals,
List **otherquals)
{
ListCell *temp;
ListCell *l;
*joinquals = NIL;
*otherquals = NIL;
foreach(temp, restrictinfo_list)
foreach(l, restrictinfo_list)
{
RestrictInfo *clause = (RestrictInfo *) lfirst(temp);
RestrictInfo *rinfo = (RestrictInfo *) lfirst(l);
if (clause->is_pushed_down)
*otherquals = lappend(*otherquals, clause->clause);
Assert(IsA(rinfo, RestrictInfo));
if (rinfo->is_pushed_down)
{
if (!rinfo->pseudoconstant)
*otherquals = lappend(*otherquals, rinfo->clause);
}
else
*joinquals = lappend(*joinquals, clause->clause);
{
/* joinquals shouldn't have been marked pseudoconstant */
Assert(!rinfo->pseudoconstant);
*joinquals = lappend(*joinquals, rinfo->clause);
}
}
}

50
src/include/nodes/relation.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.125 2006/06/06 17:59:58 tgl Exp $
* $PostgreSQL: pgsql/src/include/nodes/relation.h,v 1.126 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -114,6 +114,8 @@ typedef struct PlannerInfo
bool hasJoinRTEs; /* true if any RTEs are RTE_JOIN kind */
bool hasOuterJoins; /* true if any RTEs are outer joins */
bool hasHavingQual; /* true if havingQual was non-null */
bool hasPseudoConstantQuals; /* true if any RestrictInfo has
* pseudoconstant = true */
} PlannerInfo;
@ -524,25 +526,16 @@ typedef struct AppendPath
} AppendPath;
/*
* ResultPath represents use of a Result plan node. There are several
* applications for this:
* * To compute a variable-free targetlist (a "SELECT expressions" query).
* In this case subpath and path.parent will both be NULL. constantqual
* might or might not be empty ("SELECT expressions WHERE something").
* * To gate execution of a subplan with a one-time (variable-free) qual
* condition. path.parent is copied from the subpath.
* * To substitute for a scan plan when we have proven that no rows in
* a table will satisfy the query. subpath is NULL but path.parent
* references the not-to-be-scanned relation, and constantqual is
* a constant FALSE.
* ResultPath represents use of a Result plan node to compute a variable-free
* targetlist with no underlying tables (a "SELECT expressions" query).
* The query could have a WHERE clause, too, represented by "quals".
*
* Note that constantqual is a list of bare clauses, not RestrictInfos.
* Note that quals is a list of bare clauses, not RestrictInfos.
*/
typedef struct ResultPath
{
Path path;
Path *subpath;
List *constantqual;
List *quals;
} ResultPath;
/*
@ -732,6 +725,22 @@ typedef struct HashPath
* OR/AND structure. This is a convenience for OR indexscan processing:
* indexquals taken from either the top level or an OR subclause will have
* associated RestrictInfo nodes.
*
* The can_join flag is set true if the clause looks potentially useful as
* a merge or hash join clause, that is if it is a binary opclause with
* nonoverlapping sets of relids referenced in the left and right sides.
* (Whether the operator is actually merge or hash joinable isn't checked,
* however.)
*
* The pseudoconstant flag is set true if the clause contains no Vars of
* the current query level and no volatile functions. Such a clause can be
* pulled out and used as a one-time qual in a gating Result node. We keep
* pseudoconstant clauses in the same lists as other RestrictInfos so that
* the regular clause-pushing machinery can assign them to the correct join
* level, but they need to be treated specially for cost and selectivity
* estimates. Note that a pseudoconstant clause can never be an indexqual
* or merge or hash join clause, so it's of no interest to large parts of
* the planner.
*/
typedef struct RestrictInfo
@ -744,14 +753,9 @@ typedef struct RestrictInfo
bool outerjoin_delayed; /* TRUE if delayed by outer join */
/*
* This flag is set true if the clause looks potentially useful as a merge
* or hash join clause, that is if it is a binary opclause with
* nonoverlapping sets of relids referenced in the left and right sides.
* (Whether the operator is actually merge or hash joinable isn't checked,
* however.)
*/
bool can_join;
bool can_join; /* see comment above */
bool pseudoconstant; /* see comment above */
/* The set of relids (varnos) actually referenced in the clause: */
Relids clause_relids;

3
src/include/optimizer/clauses.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.83 2006/03/05 15:58:57 momjian Exp $
* $PostgreSQL: pgsql/src/include/optimizer/clauses.h,v 1.84 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -61,7 +61,6 @@ extern Relids find_nonnullable_rels(Node *clause);
extern bool is_pseudo_constant_clause(Node *clause);
extern bool is_pseudo_constant_clause_relids(Node *clause, Relids relids);
extern List *pull_constant_clauses(List *quals, List **constantQual);
extern bool has_distinct_clause(Query *query);
extern bool has_distinct_on_clause(Query *query);

5
src/include/optimizer/pathnode.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/pathnode.h,v 1.68 2006/06/06 17:59:58 tgl Exp $
* $PostgreSQL: pgsql/src/include/optimizer/pathnode.h,v 1.69 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -47,8 +47,7 @@ extern BitmapOrPath *create_bitmap_or_path(PlannerInfo *root,
extern TidPath *create_tidscan_path(PlannerInfo *root, RelOptInfo *rel,
List *tidquals);
extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths);
extern ResultPath *create_result_path(RelOptInfo *rel, Path *subpath,
List *constantqual);
extern ResultPath *create_result_path(List *quals);
extern MaterialPath *create_material_path(RelOptInfo *rel, Path *subpath);
extern UniquePath *create_unique_path(PlannerInfo *root, RelOptInfo *rel,
Path *subpath);

3
src/include/optimizer/planmain.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.92 2006/03/05 15:58:57 momjian Exp $
* $PostgreSQL: pgsql/src/include/optimizer/planmain.h,v 1.93 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -42,7 +42,6 @@ extern Sort *make_sort_from_sortclauses(PlannerInfo *root, List *sortcls,
Plan *lefttree);
extern Sort *make_sort_from_groupcols(PlannerInfo *root, List *groupcls,
AttrNumber *grpColIdx, Plan *lefttree);
extern List *order_qual_clauses(PlannerInfo *root, List *clauses);
extern Agg *make_agg(PlannerInfo *root, List *tlist, List *qual,
AggStrategy aggstrategy,
int numGroupCols, AttrNumber *grpColIdx,

10
src/include/optimizer/restrictinfo.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2006, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/optimizer/restrictinfo.h,v 1.36 2006/03/05 15:58:57 momjian Exp $
* $PostgreSQL: pgsql/src/include/optimizer/restrictinfo.h,v 1.37 2006/07/01 18:38:33 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -20,14 +20,18 @@
extern RestrictInfo *make_restrictinfo(Expr *clause,
bool is_pushed_down,
bool outerjoin_delayed,
bool pseudoconstant,
Relids required_relids);
extern List *make_restrictinfo_from_bitmapqual(Path *bitmapqual,
bool is_pushed_down,
bool include_predicates);
extern bool restriction_is_or_clause(RestrictInfo *restrictinfo);
extern List *get_actual_clauses(List *restrictinfo_list);
extern void get_actual_join_clauses(List *restrictinfo_list,
List **joinquals, List **otherquals);
extern List *extract_actual_clauses(List *restrictinfo_list,
bool pseudoconstant);
extern void extract_actual_join_clauses(List *restrictinfo_list,
List **joinquals,
List **otherquals);
extern List *remove_redundant_join_clauses(PlannerInfo *root,
List *restrictinfo_list,
bool isouterjoin);