diff options
Diffstat (limited to 'src/backend/catalog/pg_inherits.c')
| -rw-r--r-- | src/backend/catalog/pg_inherits.c | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/src/backend/catalog/pg_inherits.c b/src/backend/catalog/pg_inherits.c index 402ce4689e7..bbba5ae5cb0 100644 --- a/src/backend/catalog/pg_inherits.c +++ b/src/backend/catalog/pg_inherits.c @@ -13,7 +13,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/catalog/pg_inherits.c,v 1.5 2010/01/02 16:57:36 momjian Exp $ + * $PostgreSQL: pgsql/src/backend/catalog/pg_inherits.c,v 1.6 2010/02/01 19:28:56 rhaas Exp $ * *------------------------------------------------------------------------- */ @@ -148,6 +148,9 @@ find_inheritance_children(Oid parentrelId, LOCKMODE lockmode) * find_all_inheritors - * Returns a list of relation OIDs including the given rel plus * all relations that inherit from it, directly or indirectly. + * Optionally, it also returns the number of parents found for + * each such relation within the inheritance tree rooted at the + * given rel. * * The specified lock type is acquired on all child relations (but not on the * given rel; caller should already have locked it). If lockmode is NoLock @@ -155,9 +158,9 @@ find_inheritance_children(Oid parentrelId, LOCKMODE lockmode) * against possible DROPs of child relations. */ List * -find_all_inheritors(Oid parentrelId, LOCKMODE lockmode) +find_all_inheritors(Oid parentrelId, LOCKMODE lockmode, List **numparents) { - List *rels_list; + List *rels_list, *rel_numparents; ListCell *l; /* @@ -168,11 +171,13 @@ find_all_inheritors(Oid parentrelId, LOCKMODE lockmode) * doesn't fetch the next list element until the bottom of the loop. */ rels_list = list_make1_oid(parentrelId); + rel_numparents = list_make1_int(0); foreach(l, rels_list) { Oid currentrel = lfirst_oid(l); List *currentchildren; + ListCell *lc; /* Get the direct children of this rel */ currentchildren = find_inheritance_children(currentrel, lockmode); @@ -184,9 +189,37 @@ find_all_inheritors(Oid parentrelId, LOCKMODE lockmode) * loop, though theoretically there can't be any cycles in the * inheritance graph anyway.) */ - rels_list = list_concat_unique_oid(rels_list, currentchildren); + foreach(lc, currentchildren) + { + Oid child_oid = lfirst_oid(lc); + bool found = false; + ListCell *lo; + ListCell *li; + + /* if the rel is already there, bump number-of-parents counter */ + forboth(lo, rels_list, li, rel_numparents) + { + if (lfirst_oid(lo) == child_oid) + { + lfirst_int(li)++; + found = true; + break; + } + } + + /* if it's not there, add it. expect 1 parent, initially. */ + if (!found) + { + rels_list = lappend_oid(rels_list, child_oid); + rel_numparents = lappend_int(rel_numparents, 1); + } + } } + if (numparents) + *numparents = rel_numparents; + else + list_free(rel_numparents); return rels_list; } |