Revise handling of index-type-specific indexscan cost estimation, per

pghackers discussion of 5-Jan-2000.  The amopselect and amopnpages
estimators are gone, and in their place is a per-AM amcostestimate
procedure (linked to from pg_am, not pg_amop).

1 files changed, 2 insertions, 211 deletions

diff --git a/src/backend/optimizer/util/plancat.c b/src/backend/optimizer/util/plancat.c
index 6468ef528fd..4c191f02b55 100644
--- a/src/backend/optimizer/util/plancat.c
+++ b/src/backend/optimizer/util/plancat.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.44 2000/01/15 02:59:31 petere Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/optimizer/util/plancat.c,v 1.45 2000/01/22 23:50:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -136,6 +136,7 @@ find_secondary_indexes(Query *root, Index relid)
 		info->relam = relam;
 		info->pages = indexRelation->rd_rel->relpages;
 		info->tuples = indexRelation->rd_rel->reltuples;
+		info->amcostestimate = index_cost_estimator(indexRelation);
 		index_close(indexRelation);
 
 		/*
@@ -169,216 +170,6 @@ find_secondary_indexes(Query *root, Index relid)
 }
 
 /*
- * index_selectivity
- *	  Estimate the selectivity of an index scan with the given index quals.
- *
- *	  NOTE: an indexscan plan node can actually represent several passes,
- *	  but here we consider the cost of just one pass.
- *
- * 'root' is the query root
- * 'rel' is the relation being scanned
- * 'index' is the index to be used
- * 'indexquals' is the list of qual condition exprs (implicit AND semantics)
- * '*idxPages' receives an estimate of the number of index pages touched
- * '*idxSelec' receives an estimate of selectivity of the scan, ie fraction
- *		of the relation's tuples that will be retrieved
- */
-void
-index_selectivity(Query *root,
-				  RelOptInfo *rel,
-				  IndexOptInfo *index,
-				  List *indexquals,
-				  long *idxPages,
-				  Selectivity *idxSelec)
-{
-	int			relid;
-	Oid			baserelid,
-				indexrelid;
-	HeapTuple	indRel,
-				indexTuple;
-	Form_pg_class indexrelation;
-	Oid			relam;
-	Form_pg_index pgindex;
-	int			nIndexKeys;
-	float64data npages,
-				select,
-				fattr_select;
-	bool		nphack = false;
-	List	   *q;
-
-	Assert(length(rel->relids) == 1); /* must be a base rel */
-	relid = lfirsti(rel->relids);
-
-	baserelid = getrelid(relid, root->rtable);
-	indexrelid = index->indexoid;
-
-	indRel = SearchSysCacheTuple(RELOID,
-								 ObjectIdGetDatum(indexrelid),
-								 0, 0, 0);
-	if (!HeapTupleIsValid(indRel))
-		elog(ERROR, "index_selectivity: index %u not found in pg_class",
-			 indexrelid);
-	indexrelation = (Form_pg_class) GETSTRUCT(indRel);
-	relam = indexrelation->relam;
-
-	indexTuple = SearchSysCacheTuple(INDEXRELID,
-									 ObjectIdGetDatum(indexrelid),
-									 0, 0, 0);
-	if (!HeapTupleIsValid(indexTuple))
-		elog(ERROR, "index_selectivity: index %u not found in pg_index",
-			 indexrelid);
-	pgindex = (Form_pg_index) GETSTRUCT(indexTuple);
-
-	nIndexKeys = 1;
-	while (pgindex->indclass[nIndexKeys] != InvalidOid)
-		nIndexKeys++;
-
-	/*
-	 * Hack for non-functional btree npages estimation: npages =
-	 * index_pages * selectivity_of_1st_attr_clause(s) - vadim 04/24/97
-	 */
-	if (relam == BTREE_AM_OID && pgindex->indproc == InvalidOid)
-		nphack = true;
-
-	npages = 0.0;
-	select = 1.0;
-	fattr_select = 1.0;
-
-	foreach(q, indexquals)
-	{
-		Node	   *expr = (Node *) lfirst(q);
-		Oid			opno;
-		int			dummyrelid;
-		AttrNumber	attno;
-		Datum		value;
-		int			flag;
-		Oid			indclass;
-		HeapTuple	amopTuple;
-		Form_pg_amop amop;
-		float64		amopnpages,
-					amopselect;
-
-		/*
-		 * Extract info from clause.
-		 */
-		if (is_opclause(expr))
-			opno = ((Oper *) ((Expr *) expr)->oper)->opno;
-		else
-			opno = InvalidOid;
-		get_relattval(expr, relid, &dummyrelid, &attno, &value, &flag);
-
-		/*
-		 * Find the AM class for this key.
-		 */
-		if (pgindex->indproc != InvalidOid)
-		{
-			/*
-			 * Functional index: AM class is the first one defined since
-			 * functional indices have exactly one key.
-			 */
-			indclass = pgindex->indclass[0];
-		}
-		else
-		{
-			int			i;
-			indclass = InvalidOid;
-			for (i = 0; pgindex->indkey[i]; i++)
-			{
-				if (attno == pgindex->indkey[i])
-				{
-					indclass = pgindex->indclass[i];
-					break;
-				}
-			}
-		}
-		if (!OidIsValid(indclass))
-		{
-			/*
-			 * Presumably this means that we are using a functional index
-			 * clause and so had no variable to match to the index key ...
-			 * if not we are in trouble.
-			 */
-			elog(NOTICE, "index_selectivity: no key %d in index %u",
-				 attno, indexrelid);
-			continue;
-		}
-
-		amopTuple = SearchSysCacheTuple(AMOPOPID,
-										ObjectIdGetDatum(indclass),
-										ObjectIdGetDatum(opno),
-										ObjectIdGetDatum(relam),
-										0);
-		if (!HeapTupleIsValid(amopTuple))
-		{
-			/*
-			 * We might get here because indxpath.c selected a binary-
-			 * compatible index.  Try again with the compatible operator.
-			 */
-			if (opno != InvalidOid)
-			{
-				opno = indexable_operator((Expr *) expr, indclass, relam,
-										  ((flag & SEL_RIGHT) != 0));
-				amopTuple = SearchSysCacheTuple(AMOPOPID,
-												ObjectIdGetDatum(indclass),
-												ObjectIdGetDatum(opno),
-												ObjectIdGetDatum(relam),
-												0);
-			}
-			if (!HeapTupleIsValid(amopTuple))
-				elog(ERROR, "index_selectivity: no amop %u %u %u",
-					 indclass, opno, relam);
-		}
-		amop = (Form_pg_amop) GETSTRUCT(amopTuple);
-
-		if (!nphack)
-		{
-			amopnpages = (float64) fmgr(amop->amopnpages,
-										(char *) opno,
-										(char *) baserelid,
-										(char *) (int) attno,
-										(char *) value,
-										(char *) flag,
-										(char *) nIndexKeys,
-										(char *) indexrelid);
-			if (PointerIsValid(amopnpages))
-				npages += *amopnpages;
-		}
-
-		amopselect = (float64) fmgr(amop->amopselect,
-									(char *) opno,
-									(char *) baserelid,
-									(char *) (int) attno,
-									(char *) value,
-									(char *) flag,
-									(char *) nIndexKeys,
-									(char *) indexrelid);
-		if (PointerIsValid(amopselect))
-		{
-			select *= *amopselect;
-			if (nphack && attno == pgindex->indkey[0])
-				fattr_select *= *amopselect;
-		}
-	}
-
-	/*
-	 * Estimation of npages below is hack of course, but it's better than
-	 * it was before.		- vadim 04/09/97
-	 */
-	if (nphack)
-	{
-		npages = fattr_select * indexrelation->relpages;
-		*idxPages = (long) ceil((double) npages);
-	}
-	else
-	{
-		if (nIndexKeys > 1)
-			npages = npages / (1.0 + nIndexKeys);
-		*idxPages = (long) ceil((double) (npages / nIndexKeys));
-	}
-	*idxSelec = select;
-}
-
-/*
  * restriction_selectivity
  *
  * Returns the selectivity of a specified operator.