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

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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
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42
src/backend/optimizer/plan/planmain.c
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@@ -14,7 +14,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.60 2000/09/29 18:21:33 tgl Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/plan/planmain.c,v 1.61 2000/10/05 19:11:29 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -174,8 +174,6 @@ subplanner(Query *root,
List *brel;
RelOptInfo *final_rel;
Plan *resultplan;
MemoryContext mycontext;
MemoryContext oldcxt;
Path *cheapestpath;
Path *presortedpath;
@@ -227,24 +225,6 @@ subplanner(Query *root,
*/
root->query_pathkeys = canonicalize_pathkeys(root, root->query_pathkeys);
/*
* We might allocate quite a lot of storage during planning (due to
* constructing lots of Paths), but all of it can be reclaimed after
* we generate the finished Plan tree. Work in a temporary context
* to let that happen. We make the context a child of
* TransactionCommandContext so it will be freed if error abort.
*
* Note: beware of trying to move this up to the start of this routine.
* Some of the data structures built above --- notably the pathkey
* equivalence sets --- will still be needed after this routine exits.
*/
mycontext = AllocSetContextCreate(TransactionCommandContext,
"Planner",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
oldcxt = MemoryContextSwitchTo(mycontext);
/*
* Ready to do the primary planning.
*/
@@ -355,25 +335,5 @@ subplanner(Query *root,
plan_built:
/*
* Must copy the completed plan tree and its pathkeys out of temporary
* context. We also have to copy the rtable in case it contains any
* subqueries. (If it does, they'll have been modified during the
* recursive invocation of planner.c, and hence will contain substructure
* allocated in my temporary context...)
*/
MemoryContextSwitchTo(oldcxt);
resultplan = copyObject(resultplan);
root->query_pathkeys = copyObject(root->query_pathkeys);
root->rtable = copyObject(root->rtable);
/*
* Now we can release the Path storage.
*/
MemoryContextDelete(mycontext);
return resultplan;
}