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IN clauses appearing at top level of WHERE can now be handled as joins.

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There are two implementation techniques: the executor understands a new
JOIN_IN jointype, which emits at most one matching row per left-hand row,
or the result of the IN's sub-select can be fed through a DISTINCT filter
and then joined as an ordinary relation.
Along the way, some minor code cleanup in the optimizer; notably, break
out most of the jointree-rearrangement preprocessing in planner.c and
put it in a new file prep/prepjointree.c.
This commit is contained in:
Tom Lane
2003-01-20 18:55:07 +00:00
parent be2b660ecd
commit bdfbfde1b1
47 changed files with 2075 additions and 875 deletions
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121
src/backend/optimizer/plan/setrefs.c
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@ -9,7 +9,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.90 2003/01/15 23:10:32 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/setrefs.c,v 1.91 2003/01/20 18:54:52 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -31,6 +31,7 @@ typedef struct
List *outer_tlist;
List *inner_tlist;
Index acceptable_rel;
bool tlists_have_non_vars;
} join_references_context;
typedef struct
@ -44,11 +45,13 @@ static void fix_expr_references(Plan *plan, Node *node);
static bool fix_expr_references_walker(Node *node, void *context);
static void set_join_references(Join *join, List *rtable);
static void set_uppernode_references(Plan *plan, Index subvarno);
static bool targetlist_has_non_vars(List *tlist);
static List *join_references(List *clauses,
List *rtable,
List *outer_tlist,
List *inner_tlist,
Index acceptable_rel);
Index acceptable_rel,
bool tlists_have_non_vars);
static Node *join_references_mutator(Node *node,
join_references_context *context);
static Node *replace_vars_with_subplan_refs(Node *node,
@ -175,7 +178,10 @@ set_plan_references(Plan *plan, List *rtable)
rtable,
NIL,
plan->lefttree->targetlist,
(Index) 0);
(Index) 0,
targetlist_has_non_vars(plan->lefttree->targetlist));
fix_expr_references(plan,
(Node *) ((Hash *) plan)->hashkeys);
break;
case T_Material:
case T_Sort:
@ -308,23 +314,30 @@ set_join_references(Join *join, List *rtable)
Plan *inner_plan = join->plan.righttree;
List *outer_tlist = outer_plan->targetlist;
List *inner_tlist = inner_plan->targetlist;
bool tlists_have_non_vars;
tlists_have_non_vars = targetlist_has_non_vars(outer_tlist) ||
targetlist_has_non_vars(inner_tlist);
/* All join plans have tlist, qual, and joinqual */
join->plan.targetlist = join_references(join->plan.targetlist,
rtable,
outer_tlist,
inner_tlist,
(Index) 0);
(Index) 0,
tlists_have_non_vars);
join->plan.qual = join_references(join->plan.qual,
rtable,
outer_tlist,
inner_tlist,
(Index) 0);
(Index) 0,
tlists_have_non_vars);
join->joinqual = join_references(join->joinqual,
rtable,
outer_tlist,
inner_tlist,
(Index) 0);
(Index) 0,
tlists_have_non_vars);
/* Now do join-type-specific stuff */
if (IsA(join, NestLoop))
@ -350,12 +363,14 @@ set_join_references(Join *join, List *rtable)
rtable,
outer_tlist,
NIL,
innerrel);
innerrel,
tlists_have_non_vars);
innerscan->indxqual = join_references(innerscan->indxqual,
rtable,
outer_tlist,
NIL,
innerrel);
innerrel,
tlists_have_non_vars);
/*
* We must fix the inner qpqual too, if it has join clauses
* (this could happen if the index is lossy: some indxquals
@ -366,7 +381,8 @@ set_join_references(Join *join, List *rtable)
rtable,
outer_tlist,
NIL,
innerrel);
innerrel,
tlists_have_non_vars);
}
}
else if (IsA(inner_plan, TidScan))
@ -378,7 +394,8 @@ set_join_references(Join *join, List *rtable)
rtable,
outer_tlist,
NIL,
innerrel);
innerrel,
tlists_have_non_vars);
}
}
else if (IsA(join, MergeJoin))
@ -389,7 +406,8 @@ set_join_references(Join *join, List *rtable)
rtable,
outer_tlist,
inner_tlist,
(Index) 0);
(Index) 0,
tlists_have_non_vars);
}
else if (IsA(join, HashJoin))
{
@ -399,7 +417,8 @@ set_join_references(Join *join, List *rtable)
rtable,
outer_tlist,
inner_tlist,
(Index) 0);
(Index) 0,
tlists_have_non_vars);
}
}
@ -433,22 +452,7 @@ set_uppernode_references(Plan *plan, Index subvarno)
else
subplan_targetlist = NIL;
/*
* Detect whether subplan tlist has any non-Vars (typically it won't
* because it's been flattened). This allows us to save comparisons
* in common cases.
*/
tlist_has_non_vars = false;
foreach(l, subplan_targetlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(l);
if (tle->expr && !IsA(tle->expr, Var))
{
tlist_has_non_vars = true;
break;
}
}
tlist_has_non_vars = targetlist_has_non_vars(subplan_targetlist);
output_targetlist = NIL;
foreach(l, plan->targetlist)
@ -473,6 +477,27 @@ set_uppernode_references(Plan *plan, Index subvarno)
tlist_has_non_vars);
}
/*
* targetlist_has_non_vars --- are there any non-Var entries in tlist?
*
* In most cases, subplan tlists will be "flat" tlists with only Vars.
* Checking for this allows us to save comparisons in common cases.
*/
static bool
targetlist_has_non_vars(List *tlist)
{
List *l;
foreach(l, tlist)
{
TargetEntry *tle = (TargetEntry *) lfirst(l);
if (tle->expr && !IsA(tle->expr, Var))
return true;
}
return false;
}
/*
* join_references
* Creates a new set of targetlist entries or join qual clauses by
@ -505,7 +530,8 @@ join_references(List *clauses,
List *rtable,
List *outer_tlist,
List *inner_tlist,
Index acceptable_rel)
Index acceptable_rel,
bool tlists_have_non_vars)
{
join_references_context context;
@ -513,6 +539,7 @@ join_references(List *clauses,
context.outer_tlist = outer_tlist;
context.inner_tlist = inner_tlist;
context.acceptable_rel = acceptable_rel;
context.tlists_have_non_vars = tlists_have_non_vars;
return (List *) join_references_mutator((Node *) clauses, &context);
}
@ -554,6 +581,42 @@ join_references_mutator(Node *node,
/* No referent found for Var */
elog(ERROR, "join_references: variable not in subplan target lists");
}
/* Try matching more complex expressions too, if tlists have any */
if (context->tlists_have_non_vars)
{
Resdom *resdom;
resdom = tlist_member(node, context->outer_tlist);
if (resdom)
{
/* Found a matching subplan output expression */
Var *newvar;
newvar = makeVar(OUTER,
resdom->resno,
resdom->restype,
resdom->restypmod,
0);
newvar->varnoold = 0; /* wasn't ever a plain Var */
newvar->varoattno = 0;
return (Node *) newvar;
}
resdom = tlist_member(node, context->inner_tlist);
if (resdom)
{
/* Found a matching subplan output expression */
Var *newvar;
newvar = makeVar(INNER,
resdom->resno,
resdom->restype,
resdom->restypmod,
0);
newvar->varnoold = 0; /* wasn't ever a plain Var */
newvar->varoattno = 0;
return (Node *) newvar;
}
}
return expression_tree_mutator(node,
join_references_mutator,
(void *) context);