database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-09-03 15:22:11 +03:00
Code Activity

Remove some recursion in optimizer and clean up some code there.

Browse Source
This commit is contained in:
Bruce Momjian
1997-12-21 05:18:48 +00:00
parent 0808e658a7
commit 78a055a659
4 changed files with 129 additions and 122 deletions
Download Patch File Download Diff File Expand all files Collapse all files

65
src/backend/optimizer/path/prune.c
View File

@@ -7,7 +7,7 @@
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/prune.c,v 1.6 1997/09/08 21:45:08 momjian Exp $
* $Header: /cvsroot/pgsql/src/backend/optimizer/path/Attic/prune.c,v 1.7 1997/12/21 05:18:21 momjian Exp $
*
*-------------------------------------------------------------------------
*/
@@ -29,23 +29,21 @@ static List *prune_joinrel(Rel *rel, List *other_rels);
/*
* prune-joinrels--
* Removes any redundant relation entries from a list of rel nodes
* 'rel-list'.
* 'rel-list'. Obviosly, the first relation can't be a duplicate.
*
* Returns the resulting list.
*
*/
List *
void
prune_joinrels(List *rel_list)
{
List *temp_list = NIL;
List *i;
if (rel_list != NIL)
{
temp_list = lcons(lfirst(rel_list),
prune_joinrels(prune_joinrel((Rel *) lfirst(rel_list),
lnext(rel_list))));
}
return (temp_list);
/*
* rel_list can shorten while running as duplicate relations are deleted
*/
foreach(i, rel_list)
lnext(i) = prune_joinrel((Rel *) lfirst(i), lnext(i));
}
/*
@@ -62,28 +60,39 @@ prune_joinrels(List *rel_list)
static List *
prune_joinrel(Rel *rel, List *other_rels)
{
List *i = NIL;
List *t_list = NIL;
List *temp_node = NIL;
Rel *other_rel = (Rel *) NULL;
List *cur = NIL;
List *return_list = NIL;
foreach(i, other_rels)
/* find first relation that doesn't match */
foreach(cur, other_rels)
{
other_rel = (Rel *) lfirst(i);
if (same(rel->relids, other_rel->relids))
Rel *other_rel = (Rel *) lfirst(cur);
if (!same(rel->relids, other_rel->relids))
break;
}
/* we now know cur doesn't match, or is NIL */
return_list = cur;
/* remove relations that do match, we use lnext so we can remove easily */
if (cur != NIL)
{
while (lnext(cur) != NIL)
{
rel->pathlist = add_pathlist(rel,
rel->pathlist,
other_rel->pathlist);
t_list = nconc(t_list, NIL); /* XXX is this right ? */
}
else
{
temp_node = lcons(other_rel, NIL);
t_list = nconc(t_list, temp_node);
Rel *other_rel = (Rel *) lfirst(lnext(cur));
if (same(rel->relids, other_rel->relids))
{
rel->pathlist = add_pathlist(rel,
rel->pathlist,
other_rel->pathlist);
lnext(cur) = lnext(lnext(cur)); /* delete it */
}
cur = lnext(cur);
}
}
return (t_list);
return return_list;
}
/*