Add the ability to store inheritance-tree statistics in pg_statistic,

and teach ANALYZE to compute such stats for tables that have subclasses.
Per my proposal of yesterday.

autovacuum still needs to be taught about running ANALYZE on parent tables
when their subclasses change, but the feature is useful even without that.

1 files changed, 13 insertions, 17 deletions

diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 20d4180e9b9..8bc26cb6e97 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 1.263 2009/10/21 20:38:58 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.264 2009/12/29 20:11:45 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4046,20 +4046,13 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 				!vardata->freefunc)
 				elog(ERROR, "no function provided to release variable stats with");
 		}
-		else 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,
+			vardata->statsTuple = SearchSysCache(STATRELATTINH,
 												 ObjectIdGetDatum(rte->relid),
 												 Int16GetDatum(var->varattno),
-												 0, 0);
+												 BoolGetDatum(rte->inh),
+												 0);
 			vardata->freefunc = ReleaseSysCache;
 		}
 		else
@@ -4196,10 +4189,11 @@ examine_variable(PlannerInfo *root, Node *node, int varRelid,
 						else if (index->indpred == NIL)
 						{
 							vardata->statsTuple =
-								SearchSysCache(STATRELATT,
+								SearchSysCache(STATRELATTINH,
 										   ObjectIdGetDatum(index->indexoid),
 											   Int16GetDatum(pos + 1),
-											   0, 0);
+											   BoolGetDatum(false),
+											   0);
 							vardata->freefunc = ReleaseSysCache;
 						}
 						if (vardata->statsTuple)
@@ -5830,10 +5824,11 @@ btcostestimate(PG_FUNCTION_ARGS)
 		}
 		else
 		{
-			vardata.statsTuple = SearchSysCache(STATRELATT,
+			vardata.statsTuple = SearchSysCache(STATRELATTINH,
 												ObjectIdGetDatum(relid),
 												Int16GetDatum(colnum),
-												0, 0);
+												BoolGetDatum(rte->inh),
+												0);
 			vardata.freefunc = ReleaseSysCache;
 		}
 	}
@@ -5856,10 +5851,11 @@ btcostestimate(PG_FUNCTION_ARGS)
 		}
 		else
 		{
-			vardata.statsTuple = SearchSysCache(STATRELATT,
+			vardata.statsTuple = SearchSysCache(STATRELATTINH,
 												ObjectIdGetDatum(relid),
 												Int16GetDatum(colnum),
-												0, 0);
+												BoolGetDatum(false),
+												0);
 			vardata.freefunc = ReleaseSysCache;
 		}
 	}