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).

Author: tglsfdc

doc/src/sgml/catalogs.sgml

@@ -1,6 +1,6 @@
 .\" This is -*-nroff-*-
 .\" XXX standard disclaimer belongs here....
-.\" $Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.2 2000/01/11 01:40:04 tgl Exp $
+.\" $Header: /cvsroot/pgsql/doc/src/sgml/catalogs.sgml,v 2.3 2000/01/22 23:50:08 tgl Exp $
 .TH "SYSTEM CATALOGS" INTRO 03/13/94 PostgreSQL PostgreSQL
 .SH "Section 7 - System Catalogs"
 .de LS
@@ -138,6 +138,8 @@ pg_am
     regproc     ambuild	/* "build new index" function */
     regproc     amcreate 	/* - deprecated */
     regproc     amdestroy	/* - deprecated */
+    regproc     amcostestimate	/* estimate cost of an indexscan */
+	
 .fi
 .nf M
 pg_amop
@@ -148,10 +150,6 @@ pg_amop
     oid         amopopr	/* the operator */
     int2        amopstrategy	/* traversal/search strategy number
 				   to which this operator applies */
-    regproc     amopselect	/* function to calculate the operator
-				   selectivity */
-    regproc     amopnpages	/* function to calculate the number of
-				   pages that will be examined */
 .fi
 .nf M
 pg_amproc

doc/src/sgml/xindex.sgml

@@ -1,5 +1,5 @@
 <!--
-$Header: /cvsroot/pgsql/doc/src/sgml/xindex.sgml,v 1.5 1999/07/22 15:11:05 thomas Exp $
+$Header: /cvsroot/pgsql/doc/src/sgml/xindex.sgml,v 1.6 2000/01/22 23:50:08 tgl Exp $
 Postgres documentation
 -->
 
@@ -403,20 +403,9 @@ CREATE OPERATOR = (
        <entry>the <filename>oid</filename>s of the  operators  for the opclass
 	(which we'll get in just a minute)</entry>
       </row>
-      <row>
-       <entry>amopselect, amopnpages</entry>
-       <entry>cost functions</entry>
-      </row>
      </tbody>
     </tgroup>
    </table>
-
-   The cost functions are used by the query optimizer to decide whether or
-   not to use a given index in a scan.  Fortunately, these already exist.
-   The two functions we'll use are <filename>btreesel</filename>, which
-   estimates the selectivity of the <acronym>B-tree</acronym>, and
-   <filename>btreenpage</filename>, which estimates the number of pages a
-   search will touch in the tree.
   </para>
 
   <para>
@@ -460,10 +449,8 @@ CREATE OPERATOR = (
    equal, in <filename>pg_amop</filename>.  We add the instances we need:
 
    <programlisting>
-    INSERT INTO pg_amop (amopid, amopclaid, amopopr, amopstrategy,
-                amopselect, amopnpages) 
-        SELECT am.oid, opcl.oid, c.opoid, 1,
-                'btreesel'::regproc, 'btreenpage'::regproc
+    INSERT INTO pg_amop (amopid, amopclaid, amopopr, amopstrategy)
+        SELECT am.oid, opcl.oid, c.opoid, 1
         FROM pg_am am, pg_opclass opcl, complex_abs_ops_tmp c
         WHERE amname = 'btree' AND
             opcname = 'complex_abs_ops' AND
@@ -519,13 +506,11 @@ CREATE OPERATOR = (
 
   <para>
    Now we need to add a hashing strategy to allow the type to be indexed.
-   We do this by using another type in pg_am but we reuse the sames ops.
+   We do this by using another type in pg_am but we reuse the same ops.
 
    <programlisting>
-    INSERT INTO pg_amop (amopid, amopclaid, amopopr, amopstrategy,
-                amopselect, amopnpages)
-        SELECT am.oid, opcl.oid, c.opoid, 1,
-                'hashsel'::regproc, 'hashnpage'::regproc
+    INSERT INTO pg_amop (amopid, amopclaid, amopopr, amopstrategy)
+        SELECT am.oid, opcl.oid, c.opoid, 1
         FROM pg_am am, pg_opclass opcl, complex_abs_ops_tmp c
         WHERE amname = 'hash' AND
             opcname = 'complex_abs_ops' AND

src/backend/access/index/indexam.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.38 1999/12/30 05:04:50 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/access/index/indexam.c,v 1.39 2000/01/22 23:50:09 tgl Exp $
  *
  * INTERFACE ROUTINES
  *		index_open		- open an index relation by relationId
@@ -69,21 +69,6 @@
 #include "access/heapam.h"
 #include "utils/relcache.h"
 
-/* ----------------
- *	 undefine macros we aren't going to use that would otherwise
- *	 get in our way..  delete is defined in c.h and the am's are
- *	 defined in heapam.h
- * ----------------
- */
-#undef delete
-#undef aminsert
-#undef amdelete
-#undef ambeginscan
-#undef amrescan
-#undef amendscan
-#undef ammarkpos
-#undef amrestrpos
-#undef amgettuple
 
 /* ----------------------------------------------------------------
  *					macros used in index_ routines
@@ -358,6 +343,27 @@ index_getnext(IndexScanDesc scan,
 	return result;
 }
 
+/* ----------------
+ *		index_cost_estimator
+ *
+ *		Fetch the amcostestimate procedure OID for an index.
+ *
+ *		We could combine fetching and calling the procedure,
+ *		as index_insert does for example; but that would require
+ *		importing a bunch of planner/optimizer stuff into this file.
+ * ----------------
+ */
+RegProcedure
+index_cost_estimator(Relation relation)
+{
+	RegProcedure procedure;
+
+	RELATION_CHECKS;
+	GET_REL_PROCEDURE(cost_estimator, amcostestimate);
+
+	return procedure;
+}
+
 /* ----------------
  *		index_getprocid
  *

src/backend/commands/variable.c

@@ -2,7 +2,7 @@
  * Routines for handling of 'SET var TO',
  *	'SHOW var' and 'RESET var' statements.
  *
- * $Id: variable.c,v 1.27 2000/01/15 02:59:29 petere Exp $
+ * $Id: variable.c,v 1.28 2000/01/22 23:50:10 tgl Exp $
  *
  */
 
@@ -14,7 +14,8 @@
 #include "catalog/pg_shadow.h"
 #include "commands/variable.h"
 #include "miscadmin.h"
-#include "optimizer/internal.h"
+#include "optimizer/cost.h"
+#include "optimizer/paths.h"
 #include "utils/builtins.h"
 #include "utils/tqual.h"
 #include "utils/trace.h"
@@ -45,10 +46,6 @@ static bool show_XactIsoLevel(void);
 static bool reset_XactIsoLevel(void);
 static bool parse_XactIsoLevel(const char *);
 
-extern Cost _cpu_page_weight_;
-extern Cost _cpu_index_page_weight_;
-extern bool _use_geqo_;
-extern int32 _use_geqo_rels_;
 extern bool _use_keyset_query_optimizer;
 
 /*
@@ -183,23 +180,23 @@ parse_geqo(const char *value)
 
 	if (strcasecmp(tok, "on") == 0)
 	{
-		int32		geqo_rels = GEQO_RELS;
+		int		new_geqo_rels = GEQO_RELS;
 
 		if (val != NULL)
 		{
-			geqo_rels = pg_atoi(val, sizeof(int32), '\0');
-			if (geqo_rels <= 1)
+			new_geqo_rels = pg_atoi(val, sizeof(int), '\0');
+			if (new_geqo_rels <= 1)
 				elog(ERROR, "Bad value for # of relations (%s)", val);
 			pfree(val);
 		}
-		_use_geqo_ = true;
-		_use_geqo_rels_ = geqo_rels;
+		enable_geqo = true;
+		geqo_rels = new_geqo_rels;
 	}
 	else if (strcasecmp(tok, "off") == 0)
 	{
 		if ((val != NULL) && (*val != '\0'))
 			elog(ERROR, "%s does not allow a parameter", tok);
-		_use_geqo_ = false;
+		enable_geqo = false;
 	}
 	else
 		elog(ERROR, "Bad value for GEQO (%s)", value);
@@ -212,8 +209,8 @@ static bool
 show_geqo()
 {
 
-	if (_use_geqo_)
-		elog(NOTICE, "GEQO is ON beginning with %d relations", _use_geqo_rels_);
+	if (enable_geqo)
+		elog(NOTICE, "GEQO is ON beginning with %d relations", geqo_rels);
 	else
 		elog(NOTICE, "GEQO is OFF");
 	return TRUE;
@@ -224,11 +221,11 @@ reset_geqo(void)
 {
 
 #ifdef GEQO
-	_use_geqo_ = true;
+	enable_geqo = true;
 #else
-	_use_geqo_ = false;
+	enable_geqo = false;
 #endif
-	_use_geqo_rels_ = GEQO_RELS;
+	geqo_rels = GEQO_RELS;
 	return TRUE;
 }
 
@@ -240,16 +237,16 @@ reset_geqo(void)
 static bool
 parse_cost_heap(const char *value)
 {
-	float32		res;
+	float64		res;
 
 	if (value == NULL)
 	{
 		reset_cost_heap();
 		return TRUE;
 	}
 
-	res = float4in((char *) value);
-	_cpu_page_weight_ = *res;
+	res = float8in((char *) value);
+	cpu_page_weight = *res;
 
 	return TRUE;
 }
@@ -258,14 +255,14 @@ static bool
 show_cost_heap()
 {
 
-	elog(NOTICE, "COST_HEAP is %f", _cpu_page_weight_);
+	elog(NOTICE, "COST_HEAP is %f", cpu_page_weight);
 	return TRUE;
 }
 
 static bool
 reset_cost_heap()
 {
-	_cpu_page_weight_ = _CPU_PAGE_WEIGHT_;
+	cpu_page_weight = CPU_PAGE_WEIGHT;
 	return TRUE;
 }
 
@@ -277,16 +274,16 @@ reset_cost_heap()
 static bool
 parse_cost_index(const char *value)
 {
-	float32		res;
+	float64		res;
 
 	if (value == NULL)
 	{
 		reset_cost_index();
 		return TRUE;
 	}
 
-	res = float4in((char *) value);
-	_cpu_index_page_weight_ = *res;
+	res = float8in((char *) value);
+	cpu_index_page_weight = *res;
 
 	return TRUE;
 }
@@ -295,14 +292,14 @@ static bool
 show_cost_index()
 {
 
-	elog(NOTICE, "COST_INDEX is %f", _cpu_index_page_weight_);
+	elog(NOTICE, "COST_INDEX is %f", cpu_index_page_weight);
 	return TRUE;
 }
 
 static bool
 reset_cost_index()
 {
-	_cpu_index_page_weight_ = _CPU_INDEX_PAGE_WEIGHT_;
+	cpu_index_page_weight = CPU_INDEX_PAGE_WEIGHT;
 	return TRUE;
 }
 

src/backend/nodes/copyfuncs.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.100 2000/01/17 00:14:46 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/copyfuncs.c,v 1.101 2000/01/22 23:50:11 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1031,6 +1031,7 @@ _copyIndexOptInfo(IndexOptInfo *from)
 	}
 
 	newnode->relam = from->relam;
+	newnode->amcostestimate = from->amcostestimate;
 	newnode->indproc = from->indproc;
 	Node_Copy(from, newnode, indpred);
 

src/backend/nodes/readfuncs.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.78 2000/01/14 00:53:21 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/nodes/readfuncs.c,v 1.79 2000/01/22 23:50:12 tgl Exp $
  *
  * NOTES
  *	  Most of the read functions for plan nodes are tested. (In fact, they
@@ -1330,34 +1330,6 @@ _readRelOptInfo()
 	return local_node;
 }
 
-/* ----------------
- *		_readIndexOptInfo
- * ----------------
- */
-static IndexOptInfo *
-_readIndexOptInfo()
-{
-	IndexOptInfo *local_node;
-	char	   *token;
-	int			length;
-
-	local_node = makeNode(IndexOptInfo);
-
-	token = lsptok(NULL, &length);		/* get :indexoid */
-	token = lsptok(NULL, &length);		/* now read it */
-	local_node->indexoid = (Oid) atoi(token);
-
-	token = lsptok(NULL, &length);		/* get :pages */
-	token = lsptok(NULL, &length);		/* now read it */
-	local_node->pages = atol(token);
-
-	token = lsptok(NULL, &length);		/* get :tuples */
-	token = lsptok(NULL, &length);		/* now read it */
-	local_node->tuples = atof(token);
-
-	return local_node;
-}
-
 /* ----------------
  *		_readTargetEntry
  * ----------------
@@ -1900,8 +1872,6 @@ parsePlanString(void)
 		return_value = _readEState();
 	else if (length == 10 && strncmp(token, "RELOPTINFO", length) == 0)
 		return_value = _readRelOptInfo();
-	else if (length == 12 && strncmp(token, "INDEXOPTINFO", length) == 0)
-		return_value = _readIndexOptInfo();
 	else if (length == 11 && strncmp(token, "TARGETENTRY", length) == 0)
 		return_value = _readTargetEntry();
 	else if (length == 3 && strncmp(token, "RTE", length) == 0)