database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-13 07:41:39 +03:00
Code Activity

Teach planner about some cases where a restriction clause can be

Browse Source 
propagated inside an outer join.  In particular, given
LEFT JOIN ON (A = B) WHERE A = constant, we cannot conclude that
B = constant at the top level (B might be null instead), but we
can nonetheless put a restriction B = constant into the quals for
B's relation, since no inner-side rows not meeting that condition
can contribute to the final result.  Similarly, given
FULL JOIN USING (J) WHERE J = constant, we can't directly conclude
that either input J variable = constant, but it's OK to push such
quals into each input rel.  Per recent gripe from Kim Bisgaard.
Along the way, remove 'valid_everywhere' flag from RestrictInfo,
as on closer analysis it was not being used for anything, and was
defined backwards anyway.
This commit is contained in:
Tom Lane
2005-07-02 23:00:42 +00:00
parent ea1e2b948d
commit cc5e80b8d1
13 changed files with 424 additions and 114 deletions
Download Patch File Download Diff File Expand all files Collapse all files

46
src/backend/optimizer/util/restrictinfo.c
View File

@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.37 2005/06/09 04:19:00 tgl Exp $
* $PostgreSQL: pgsql/src/backend/optimizer/util/restrictinfo.c,v 1.38 2005/07/02 23:00:41 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -24,11 +24,9 @@
static RestrictInfo *make_restrictinfo_internal(Expr *clause,
Expr *orclause,
bool is_pushed_down,
bool valid_everywhere,
Relids required_relids);
static Expr *make_sub_restrictinfos(Expr *clause,
bool is_pushed_down,
bool valid_everywhere);
bool is_pushed_down);
static RestrictInfo *join_clause_is_redundant(PlannerInfo *root,
RestrictInfo *rinfo,
List *reference_list,
@ -40,8 +38,8 @@ static RestrictInfo *join_clause_is_redundant(PlannerInfo *root,
*
* Build a RestrictInfo node containing the given subexpression.
*
* The is_pushed_down and valid_everywhere flags must be supplied by the
* caller. required_relids can be NULL, in which case it defaults to the
* The is_pushed_down flag 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
@ -49,23 +47,19 @@ static RestrictInfo *join_clause_is_redundant(PlannerInfo *root,
* later.
*/
RestrictInfo *
make_restrictinfo(Expr *clause, bool is_pushed_down, bool valid_everywhere,
Relids required_relids)
make_restrictinfo(Expr *clause, bool is_pushed_down, Relids required_relids)
{
/*
* If it's an OR clause, build a modified copy with RestrictInfos
* inserted above each subclause of the top-level AND/OR structure.
*/
if (or_clause((Node *) clause))
return (RestrictInfo *) make_sub_restrictinfos(clause,
is_pushed_down,
valid_everywhere);
return (RestrictInfo *) make_sub_restrictinfos(clause, is_pushed_down);
/* 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, valid_everywhere,
return make_restrictinfo_internal(clause, NULL, is_pushed_down,
required_relids);
}
@ -84,9 +78,7 @@ make_restrictinfo(Expr *clause, bool is_pushed_down, bool valid_everywhere,
* a specialized routine to allow sharing of RestrictInfos.
*/
List *
make_restrictinfo_from_bitmapqual(Path *bitmapqual,
bool is_pushed_down,
bool valid_everywhere)
make_restrictinfo_from_bitmapqual(Path *bitmapqual, bool is_pushed_down)
{
List *result;
@ -101,8 +93,7 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
List *sublist;
sublist = make_restrictinfo_from_bitmapqual((Path *) lfirst(l),
is_pushed_down,
valid_everywhere);
is_pushed_down);
result = list_concat(result, sublist);
}
}
@ -118,8 +109,7 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
List *sublist;
sublist = make_restrictinfo_from_bitmapqual((Path *) lfirst(l),
is_pushed_down,
valid_everywhere);
is_pushed_down);
if (sublist == NIL)
{
/* constant TRUE input yields constant TRUE OR result */
@ -137,7 +127,6 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
list_make1(make_restrictinfo_internal(make_orclause(withoutris),
make_orclause(withris),
is_pushed_down,
valid_everywhere,
NULL));
}
else if (IsA(bitmapqual, IndexPath))
@ -162,15 +151,13 @@ make_restrictinfo_from_bitmapqual(Path *bitmapqual,
*/
static RestrictInfo *
make_restrictinfo_internal(Expr *clause, Expr *orclause,
bool is_pushed_down, bool valid_everywhere,
Relids required_relids)
bool is_pushed_down, Relids required_relids)
{
RestrictInfo *restrictinfo = makeNode(RestrictInfo);
restrictinfo->clause = clause;
restrictinfo->orclause = orclause;
restrictinfo->is_pushed_down = is_pushed_down;
restrictinfo->valid_everywhere = valid_everywhere;
restrictinfo->can_join = false; /* may get set below */
/*
@ -250,8 +237,7 @@ make_restrictinfo_internal(Expr *clause, Expr *orclause,
* simple clauses are valid RestrictInfos.
*/
static Expr *
make_sub_restrictinfos(Expr *clause, bool is_pushed_down,
bool valid_everywhere)
make_sub_restrictinfos(Expr *clause, bool is_pushed_down)
{
if (or_clause((Node *) clause))
{
@ -261,12 +247,10 @@ make_sub_restrictinfos(Expr *clause, bool is_pushed_down,
foreach(temp, ((BoolExpr *) clause)->args)
orlist = lappend(orlist,
make_sub_restrictinfos(lfirst(temp),
is_pushed_down,
valid_everywhere));
is_pushed_down));
return (Expr *) make_restrictinfo_internal(clause,
make_orclause(orlist),
is_pushed_down,
valid_everywhere,
NULL);
}
else if (and_clause((Node *) clause))
@ -277,15 +261,13 @@ make_sub_restrictinfos(Expr *clause, bool is_pushed_down,
foreach(temp, ((BoolExpr *) clause)->args)
andlist = lappend(andlist,
make_sub_restrictinfos(lfirst(temp),
is_pushed_down,
valid_everywhere));
is_pushed_down));
return make_andclause(andlist);
}
else
return (Expr *) make_restrictinfo_internal(clause,
NULL,
is_pushed_down,
valid_everywhere,
NULL);
}