*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.15 1997/12/27 06:41:17 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/optimizer/prep/prepunion.c,v 1.16 1997/12/29 01:12:48 momjian Exp $
*
*-------------------------------------------------------------------------
*/
#include "optimizer/planner.h"
#include "optimizer/planmain.h"
-static List *plan_union_query(List *relids, Index rt_index,
- RangeTblEntry *rt_entry, Query *parse, UnionFlag flag,
+static List *plan_inherit_query(List *relids, Index rt_index,
+ RangeTblEntry *rt_entry, Query *parse,
List **union_rtentriesPtr);
static RangeTblEntry *new_rangetable_entry(Oid new_relid,
RangeTblEntry *old_entry);
/*
- * find-all-inheritors -
- * Returns a list of relids corresponding to relations that inherit
- * attributes from any relations listed in either of the argument relid
- * lists.
+ * plan-union-queries--
+ *
+ * Plans the queries for a given UNION.
+ *
+ * Returns a list containing a list of plans and a list of rangetables
*/
-List *
-find_all_inheritors(List *unexamined_relids,
- List *examined_relids)
+Append *
+plan_union_queries(Query *parse)
{
- List *new_inheritors = NIL;
- List *new_examined_relids = NIL;
- List *new_unexamined_relids = NIL;
-
+ List *union_plans = NIL, *ulist, *unionall_queries, *union_rts,
+ *last_union = NIL;
+ bool union_all_found = false, union_found = false,
+ last_unionall_flag = false;
+
/*
- * Find all relations which inherit from members of
- * 'unexamined-relids' and store them in 'new-inheritors'.
+ * Do we need to split up our unions because we have UNION
+ * and UNION ALL?
+ *
+ * We are checking for the case of:
+ * SELECT 1
+ * UNION
+ * SELECT 2
+ * UNION
+ * SELECT 3
+ * UNION ALL
+ * SELECT 4
+ * UNION ALL
+ * SELECT 5
+ *
+ * where we have to do a DISTINCT on the output of the first three
+ * queries, then add the rest. If they have used UNION and
+ * UNION ALL, we grab all queries up to the last UNION query,
+ * make them their own UNION with the owner as the first query
+ * in the list. Then, we take the remaining queries, which is UNION
+ * ALL, and add them to the list of union queries.
+ *
+ * So the above query becomes:
+ *
+ * Append Node
+ * {
+ * Sort and Unique
+ * {
+ * Append Node
+ * {
+ * SELECT 1 This is really a sub-UNION,
+ * unionClause We run a DISTINCT on these.
+ * {
+ * SELECT 2
+ * SELECT 3
+ * }
+ * }
+ * }
+ * SELECT 4
+ * SELECT 5
+ * }
+ *
*/
- List *rels = NIL;
- List *newrels = NIL;
- foreach(rels, unexamined_relids)
+ foreach(ulist, parse->unionClause)
{
- newrels = (List *) LispUnioni(find_inheritance_children(lfirsti(rels)),
- newrels);
- }
- new_inheritors = newrels;
+ Query *union_query = lfirst(ulist);
- new_examined_relids = (List *) LispUnioni(examined_relids, unexamined_relids);
- new_unexamined_relids = set_differencei(new_inheritors,
- new_examined_relids);
+ if (union_query->unionall)
+ union_all_found = true;
+ else
+ {
+ union_found = true;
+ last_union = ulist;
+ }
+ last_unionall_flag = union_query->unionall;
+ }
- if (new_unexamined_relids == NULL)
+ /* Is this a simple one */
+ if (!union_all_found ||
+ !union_found ||
+ /* A trailing UNION negates the affect of earlier UNION ALLs */
+ !last_unionall_flag)
{
- return (new_examined_relids);
+ List *hold_unionClause = parse->unionClause;
+
+ parse->unionClause = NIL; /* prevent recursion */
+ union_plans = lcons(planner(parse), NIL);
+ union_rts = lcons(parse->rtable, NIL);
+
+ foreach(ulist, hold_unionClause)
+ {
+ Query *union_query = lfirst(ulist);
+
+ union_plans = lappend(union_plans, planner(union_query));
+ union_rts = lappend(union_rts, union_query->rtable);
+ }
}
else
{
- return (find_all_inheritors(new_unexamined_relids,
- new_examined_relids));
- }
-}
+ /*
+ * We have mixed unions and non-unions
+ *
+ * We need to restructure this to put the UNIONs on their own
+ * so we can do a DISTINCT.
+ */
-/*
- * first-matching-rt-entry -
- * Given a rangetable, find the first rangetable entry that represents
- * the appropriate special case.
- *
- * Returns a rangetable index., Returns -1 if no matches
- */
-int
-first_matching_rt_entry(List *rangetable, UnionFlag flag)
-{
- int count = 0;
- List *temp = NIL;
+ /* save off everthing past the last UNION */
+ unionall_queries = lnext(last_union);
- foreach(temp, rangetable)
- {
- RangeTblEntry *rt_entry = lfirst(temp);
+ /* clip off the list to remove the trailing UNION ALLs */
+ lnext(last_union) = NIL;
+
+ /*
+ * Recursion, but UNION only.
+ * The last one is a UNION, so it will not come here in recursion,
+ */
+ union_plans = lcons(planner(parse), NIL);
+ union_rts = lcons(parse->rtable, NIL);
- switch (flag)
+ /* Append the remainging UNION ALLs */
+ foreach(ulist, unionall_queries)
{
- case INHERITS_FLAG:
- if (rt_entry->inh)
- return count + 1;
- break;
- default:
- break;
+ Query *unionall_query = lfirst(ulist);
+
+ union_plans = lappend(union_plans, planner(unionall_query));
+ union_rts = lappend(union_rts, unionall_query->rtable);
}
- count++;
}
+
+ /* We have already split UNION and UNION ALL and we made it consistent */
+ if (!last_unionall_flag)
+ {
+ parse->uniqueFlag = "*";
+ parse->sortClause = transformSortClause(NULL, NIL,
+ ((Plan *) lfirst(union_plans))->targetlist, "*");
+ }
+ else
+ {
+ /* needed so we don't take the flag from the first query */
+ parse->uniqueFlag = NULL;
+ parse->sortClause = NIL;
+ }
+
+ parse->havingQual = NULL;
+ parse->qry_numAgg = 0;
+ parse->qry_aggs = NULL;
- return (-1);
+ return (make_append(union_plans,
+ union_rts,
+ 0,
+ NULL,
+ ((Plan *) lfirst(union_plans))->targetlist));
}
/*
- * plan-union-queries--
+ * plan-inherit-queries--
*
* Plans the queries for a given parent relation.
*
* XXX - what exactly does this mean, look for make_append
*/
Append *
-plan_union_queries(Index rt_index,
- Query *parse,
- UnionFlag flag)
+plan_inherit_queries(Query *parse, Index rt_index)
{
List *union_plans = NIL;
- switch (flag)
- {
- case INHERITS_FLAG:
- {
- List *rangetable = parse->rtable;
- RangeTblEntry *rt_entry = rt_fetch(rt_index, rangetable);
- List *union_rt_entries = NIL;
- List *union_relids = NIL;
-
- union_relids =
- find_all_inheritors(lconsi(rt_entry->relid,
- NIL),
- NIL);
- /*
- * Remove the flag for this relation, since we're about to handle it
- * (do it before recursing!). XXX destructive parse tree change
- */
- switch (flag)
- {
- case INHERITS_FLAG:
- rt_fetch(rt_index, rangetable)->inh = false;
- break;
- default:
- break;
- }
-
- /*
- * XXX - can't find any reason to sort union-relids as paul did, so
- * we're leaving it out for now (maybe forever) - jeff & lp
- *
- * [maybe so. btw, jeff & lp did the lisp conversion, according to Paul.
- * -- ay 10/94.]
- */
- union_plans = plan_union_query(union_relids, rt_index, rt_entry,
- parse, flag, &union_rt_entries);
-
- return (make_append(union_plans,
- NULL,
- rt_index,
- union_rt_entries,
- ((Plan *) lfirst(union_plans))->targetlist));
- break;
- }
- case UNION_FLAG:
- {
- List *ulist, *hold_union, *union_plans, *union_rts;
-
- hold_union = parse->unionClause;
- parse->unionClause = NULL; /* prevent looping */
+ List *rangetable = parse->rtable;
+ RangeTblEntry *rt_entry = rt_fetch(rt_index, rangetable);
+ List *union_rt_entries = NIL;
+ List *union_relids = NIL;
- union_plans = lcons(planner(parse), NIL);
- union_rts = lcons(parse->rtable, NIL);
- foreach(ulist, hold_union)
- {
- Query *u = lfirst(ulist);
-
- union_plans = lappend(union_plans, planner(u));
- union_rts = lappend(union_rts, u->rtable);
- }
-
- /* We have already split UNION and UNION ALL */
- if (!((Query *)lfirst(hold_union))->unionall)
- {
- parse->uniqueFlag = "*";
- parse->sortClause = transformSortClause(NULL, NIL,
- ((Plan *)lfirst(union_plans))->targetlist, "*");
- }
- else
- {
- /* needed so we don't take the flag from the first query */
- parse->uniqueFlag = NULL;
- parse->sortClause = NIL;
- }
-
- parse->havingQual = NULL;
- parse->qry_numAgg = 0;
- parse->qry_aggs = NULL;
+ union_relids =
+ find_all_inheritors(lconsi(rt_entry->relid,
+ NIL),
+ NIL);
+ /*
+ * Remove the flag for this relation, since we're about to handle it
+ * (do it before recursing!). XXX destructive parse tree change
+ */
+ rt_fetch(rt_index, rangetable)->inh = false;
- return (make_append(union_plans, union_rts,
- rt_index /* is 0, none */, NULL,
- ((Plan *) lfirst(union_plans))->targetlist));
- }
- break;
+ union_plans = plan_inherit_query(union_relids, rt_index, rt_entry,
+ parse, &union_rt_entries);
-#ifdef NOT_USED
- case VERSION_FLAG:
- union_relids = VersionGetParents(rt_entry->relid);
- break;
-#endif
- default:
- /* do nothing */
- break;
- }
- return NULL;
-
- return ((Append*)NULL); /* to make gcc happy */
+ return (make_append(union_plans,
+ NULL,
+ rt_index,
+ union_rt_entries,
+ ((Plan *) lfirst(union_plans))->targetlist));
}
-
/*
- * plan-union-query--
+ * plan-inherit-query--
* Returns a list of plans for 'relids' and a list of range table entries
* in union_rtentries.
*/
static List *
-plan_union_query(List *relids,
+plan_inherit_query(List *relids,
Index rt_index,
RangeTblEntry *rt_entry,
Query *root,
- UnionFlag flag,
List **union_rtentriesPtr)
{
List *i;
return (union_plans);
}
+/*
+ * find-all-inheritors -
+ * Returns a list of relids corresponding to relations that inherit
+ * attributes from any relations listed in either of the argument relid
+ * lists.
+ */
+List *
+find_all_inheritors(List *unexamined_relids,
+ List *examined_relids)
+{
+ List *new_inheritors = NIL;
+ List *new_examined_relids = NIL;
+ List *new_unexamined_relids = NIL;
+
+ /*
+ * Find all relations which inherit from members of
+ * 'unexamined-relids' and store them in 'new-inheritors'.
+ */
+ List *rels = NIL;
+ List *newrels = NIL;
+
+ foreach(rels, unexamined_relids)
+ {
+ newrels = (List *) LispUnioni(find_inheritance_children(lfirsti(rels)),
+ newrels);
+ }
+ new_inheritors = newrels;
+
+ new_examined_relids = (List *) LispUnioni(examined_relids, unexamined_relids);
+ new_unexamined_relids = set_differencei(new_inheritors,
+ new_examined_relids);
+
+ if (new_unexamined_relids == NULL)
+ {
+ return (new_examined_relids);
+ }
+ else
+ {
+ return (find_all_inheritors(new_unexamined_relids,
+ new_examined_relids));
+ }
+}
+
+/*
+ * first-inherit-rt-entry -
+ * Given a rangetable, find the first rangetable entry that represents
+ * the appropriate special case.
+ *
+ * Returns a rangetable index., Returns -1 if no matches
+ */
+int
+first_inherit_rt_entry(List *rangetable)
+{
+ int count = 0;
+ List *temp = NIL;
+
+ foreach(temp, rangetable)
+ {
+ RangeTblEntry *rt_entry = lfirst(temp);
+
+ if (rt_entry->inh)
+ return count + 1;
+ count++;
+ }
+
+ return -1;
+}
+
/*
* new-rangetable-entry -
* Replaces the name and relid of 'old-entry' with the values for
Oid old_typeid,
new_typeid;
-/* old_typeid = RelationIdGetTypeId(old_relid);*/
-/* new_typeid = RelationIdGetTypeId(new_relid);*/
old_typeid = old_relid;
new_typeid = new_relid;
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