diff options
Diffstat (limited to 'src/backend/optimizer/prep/prepunion.c')
| -rw-r--r-- | src/backend/optimizer/prep/prepunion.c | 30 |
1 files changed, 16 insertions, 14 deletions
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c index 1fedd9791ca..0521956235e 100644 --- a/src/backend/optimizer/prep/prepunion.c +++ b/src/backend/optimizer/prep/prepunion.c @@ -14,7 +14,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.124 2005/06/10 02:21:05 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/prep/prepunion.c,v 1.125 2005/07/28 22:27:00 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -706,21 +706,24 @@ tlist_same_datatypes(List *tlist, List *colTypes, bool junkOK) List * find_all_inheritors(Oid parentrel) { - List *examined_relids = NIL; - List *unexamined_relids = list_make1_oid(parentrel); + List *rels_list; + ListCell *l; - /* - * While the queue of unexamined relids is nonempty, remove the first - * element, mark it examined, and find its direct descendants. NB: - * cannot use foreach(), since we modify the queue inside loop. + /* + * We build a list starting with the given rel and adding all direct and + * indirect children. We can use a single list as both the record of + * already-found rels and the agenda of rels yet to be scanned for more + * children. This is a bit tricky but works because the foreach() macro + * doesn't fetch the next list element until the bottom of the loop. */ - while (unexamined_relids != NIL) + rels_list = list_make1_oid(parentrel); + + foreach(l, rels_list) { - Oid currentrel = linitial_oid(unexamined_relids); + Oid currentrel = lfirst_oid(l); List *currentchildren; - unexamined_relids = list_delete_first(unexamined_relids); - examined_relids = lappend_oid(examined_relids, currentrel); + /* Get the direct children of this rel */ currentchildren = find_inheritance_children(currentrel); /* @@ -730,11 +733,10 @@ find_all_inheritors(Oid parentrel) * into an infinite loop, though theoretically there can't be any * cycles in the inheritance graph anyway.) */ - currentchildren = list_difference_oid(currentchildren, examined_relids); - unexamined_relids = list_union_oid(unexamined_relids, currentchildren); + rels_list = list_concat_unique_oid(rels_list, currentchildren); } - return examined_relids; + return rels_list; } /* |