database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-11-19 13:42:17 +03:00
Code Activity

Reimplementation of UNION/INTERSECT/EXCEPT. INTERSECT/EXCEPT now meet the

Browse Source 
SQL92 semantics, including support for ALL option.  All three can be used
in subqueries and views.  DISTINCT and ORDER BY work now in views, too.
This rewrite fixes many problems with cross-datatype UNIONs and INSERT/SELECT
where the SELECT yields different datatypes than the INSERT needs.  I did
that by making UNION subqueries and SELECT in INSERT be treated like
subselects-in-FROM, thereby allowing an extra level of targetlist where the
datatype conversions can be inserted safely.
INITDB NEEDED!
This commit is contained in:
Tom Lane
2000-10-05 19:11:39 +00:00
parent 5292637f52
commit 05e3d0ee86
51 changed files with 2621 additions and 1935 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
src/backend/optimizer/plan/subselect.c
View File

@@ -7,7 +7,7 @@
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.42 2000/09/29 18:21:33 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/subselect.c,v 1.43 2000/10/05 19:11:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -29,7 +29,8 @@
Index PlannerQueryLevel; /* level of current query */
List *PlannerInitPlan; /* init subplans for current query */
List *PlannerParamVar; /* to get Var from Param->paramid */
int PlannerPlanId; /* to assign unique ID to subquery plans */
int PlannerPlanId = 0; /* to assign unique ID to subquery plans */
/*--------------------
* PlannerParamVar is a list of Var nodes, wherein the n'th entry
@@ -81,7 +82,7 @@ replace_var(Var *var)
/*
* If there's already a PlannerParamVar entry for this same Var, just
* use it. NOTE: in situations involving UNION or inheritance, it is
* use it. NOTE: in sufficiently complex querytrees, it is
* possible for the same varno/varlevel to refer to different RTEs in
* different parts of the parsetree, so that different fields might
* end up sharing the same Param number. As long as we check the
@@ -128,11 +129,6 @@ make_subplan(SubLink *slink)
Plan *plan;
List *lst;
Node *result;
List *saved_ip = PlannerInitPlan;
PlannerInitPlan = NULL;
PlannerQueryLevel++; /* we become child */
/*
* Check to see if this node was already processed; if so we have
@@ -181,45 +177,30 @@ make_subplan(SubLink *slink)
else
tuple_fraction = -1.0; /* default behavior */
/*
* Generate the plan for the subquery.
*/
node->plan = plan = subquery_planner(subquery, tuple_fraction);
/*
* Assign subPlan, extParam and locParam to plan nodes. At the moment,
* SS_finalize_plan doesn't handle initPlan-s and so we assign them to
* the topmost plan node and take care about its extParam too.
*/
(void) SS_finalize_plan(plan);
plan->initPlan = PlannerInitPlan;
node->plan_id = PlannerPlanId++; /* Assign unique ID to this SubPlan */
/* Create extParam list as union of InitPlan-s' lists */
foreach(lst, PlannerInitPlan)
{
List *lp;
foreach(lp, ((SubPlan *) lfirst(lst))->plan->extParam)
{
if (!intMember(lfirsti(lp), plan->extParam))
plan->extParam = lappendi(plan->extParam, lfirsti(lp));
}
}
/* and now we are parent again */
PlannerInitPlan = saved_ip;
PlannerQueryLevel--;
node->plan_id = PlannerPlanId++;
node->rtable = subquery->rtable;
node->sublink = slink;
slink->subselect = NULL; /* cool ?! see error check above! */
/* make parParam list of params coming from current query level */
/*
* Make parParam list of params that current query level will pass
* to this child plan.
*/
foreach(lst, plan->extParam)
{
Var *var = nth(lfirsti(lst), PlannerParamVar);
int paramid = lfirsti(lst);
Var *var = nth(paramid, PlannerParamVar);
/* note varlevelsup is absolute level number */
if (var->varlevelsup == PlannerQueryLevel)
node->parParam = lappendi(node->parParam, lfirsti(lst));
node->parParam = lappendi(node->parParam, paramid);
}
/*
@@ -625,6 +606,11 @@ SS_finalize_plan(Plan *plan)
SS_finalize_plan((Plan *) lfirst(lst)));
break;
case T_SubqueryScan:
results.paramids = set_unioni(results.paramids,
SS_finalize_plan(((SubqueryScan *) plan)->subplan));
break;
case T_IndexScan:
finalize_primnode((Node *) ((IndexScan *) plan)->indxqual,
&results);
@@ -667,10 +653,10 @@ SS_finalize_plan(Plan *plan)
case T_Agg:
case T_SeqScan:
case T_SubqueryScan:
case T_Material:
case T_Sort:
case T_Unique:
case T_SetOp:
case T_Group:
break;
@@ -689,17 +675,18 @@ SS_finalize_plan(Plan *plan)
foreach(lst, results.paramids)
{
Var *var = nth(lfirsti(lst), PlannerParamVar);
int paramid = lfirsti(lst);
Var *var = nth(paramid, PlannerParamVar);
/* note varlevelsup is absolute level number */
if (var->varlevelsup < PlannerQueryLevel)
extParam = lappendi(extParam, lfirsti(lst));
extParam = lappendi(extParam, paramid);
else if (var->varlevelsup > PlannerQueryLevel)
elog(ERROR, "SS_finalize_plan: plan shouldn't reference subplan's variable");
else
{
Assert(var->varno == 0 && var->varattno == 0);
locParam = lappendi(locParam, lfirsti(lst));
locParam = lappendi(locParam, paramid);
}
}