From 427c6b5b984928972e955f4477c6ba64edbb66cc Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Tue, 2 May 2006 04:34:18 +0000 Subject: Avoid assuming that statistics for a parent relation reflect the properties of the union of its child relations as well. This might have been a good idea when it was originally coded, but it's a fatally bad idea when inheritance is being used for partitioning. It's better to have no stats at all than completely misleading stats. Per report from Mark Liberman. The bug arguably exists all the way back, but I've only patched HEAD and 8.1 because we weren't particularly trying to support partitioning before 8.1. Eventually we ought to look at deriving union statistics instead of just punting, but for now the drop kick looks good. --- src/backend/utils/adt/selfuncs.c | 18 +++++++++++++----- 1 file changed, 13 insertions(+), 5 deletions(-) (limited to 'src/backend/utils/adt/selfuncs.c') diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c index 082089b9f11..5f830ef0cd3 100644 --- a/src/backend/utils/adt/selfuncs.c +++ b/src/backend/utils/adt/selfuncs.c @@ -15,7 +15,7 @@ * * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.203 2006/04/27 17:52:40 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.204 2006/05/02 04:34:18 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -3265,19 +3265,27 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid, (varRelid == 0 || varRelid == ((Var *) basenode)->varno)) { Var *var = (Var *) basenode; - Oid relid; + RangeTblEntry *rte; vardata->var = basenode; /* return Var without relabeling */ vardata->rel = find_base_rel(root, var->varno); vardata->atttype = var->vartype; vardata->atttypmod = var->vartypmod; - relid = getrelid(var->varno, root->parse->rtable); + rte = rt_fetch(var->varno, root->parse->rtable); - if (OidIsValid(relid)) + if (rte->inh) + { + /* + * XXX This means the Var represents a column of an append relation. + * Later add code to look at the member relations and try to derive + * some kind of combined statistics? + */ + } + else if (rte->rtekind == RTE_RELATION) { vardata->statsTuple = SearchSysCache(STATRELATT, - ObjectIdGetDatum(relid), + ObjectIdGetDatum(rte->relid), Int16GetDatum(var->varattno), 0, 0); } -- cgit v1.2.3