Document that get_attstatsslot/free_attstatsslot only need to be passed

tglsfdc · tglsfdc · commit 0cc0d0822ddf · 2005-10-11T17:27:14.000Z
valid type information if they are asked to fetch the values part of a
pg_statistic slot; these arguments are unneeded if fetching only the
numbers part.  Use this to save a catcache lookup in btcostestimate,
which is looking like a bit of a hotspot in recent profiling.  Not a
big savings, but since it's essentially free, might as well do it.
diff --git 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 1.189 2005/09/24 22:54:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.190 2005/10/11 17:27:14 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4466,15 +4466,10 @@ btcostestimate(PG_FUNCTION_ARGS)
 
 	if (HeapTupleIsValid(tuple))
 	{
-		Oid			typid;
-		int32		typmod;
 		float4	   *numbers;
 		int			nnumbers;
 
-		/* XXX this code would break with different storage type */
-		get_atttypetypmod(relid, colnum, &typid, &typmod);
-
-		if (get_attstatsslot(tuple, typid, typmod,
+		if (get_attstatsslot(tuple, InvalidOid, 0,
 							 STATISTIC_KIND_CORRELATION,
 							 index->ordering[0],
 							 NULL, NULL, &numbers, &nnumbers))
@@ -4489,7 +4484,7 @@ btcostestimate(PG_FUNCTION_ARGS)
 			else
 				*indexCorrelation = varCorrelation;
 
-			free_attstatsslot(typid, NULL, 0, numbers, nnumbers);
+			free_attstatsslot(InvalidOid, NULL, 0, numbers, nnumbers);
 		}
 		ReleaseSysCache(tuple);
 	}
diff --git a/src/backend/utils/cache/lsyscache.c b/src/backend/utils/cache/lsyscache.c
@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.127 2005/08/12 21:49:47 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/cache/lsyscache.c,v 1.128 2005/10/11 17:27:14 tgl Exp $
  *
  * NOTES
  *	  Eventually, the index information should go through here, too.
@@ -1841,8 +1841,8 @@ get_attavgwidth(Oid relid, AttrNumber attnum)
  * entry, and we don't want to repeat the cache lookup unnecessarily.
  *
  * statstuple: pg_statistics tuple to be examined.
- * atttype: type OID of attribute.
- * atttypmod: typmod of attribute.
+ * atttype: type OID of attribute (can be InvalidOid if values == NULL).
+ * atttypmod: typmod of attribute (can be 0 if values == NULL).
  * reqkind: STAKIND code for desired statistics slot kind.
  * reqop: STAOP value wanted, or InvalidOid if don't care.
  * values, nvalues: if not NULL, the slot's stavalues are extracted.
@@ -1960,6 +1960,12 @@ get_attstatsslot(HeapTuple statstuple,
 	return true;
 }
 
+/*
+ * free_attstatsslot
+ *		Free data allocated by get_attstatsslot
+ *
+ * atttype need be valid only if values != NULL.
+ */
 void
 free_attstatsslot(Oid atttype,
 				  Datum *values, int nvalues,

Original file line number	Diff line number	Diff line change
`@@ -15,7 +15,7 @@`
`15`	`15`	`*`
`16`	`16`	`*`
`17`	`17`	`* IDENTIFICATION`
`18`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.189 2005/09/24 22:54:38 tgl Exp $`
	`18`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.190 2005/10/11 17:27:14 tgl Exp $`
`19`	`19`	`*`
`20`	`20`	`*-------------------------------------------------------------------------`
`21`	`21`	`*/`
`@@ -4466,15 +4466,10 @@ btcostestimate(PG_FUNCTION_ARGS)`
`4466`	`4466`
`4467`	`4467`	`if (HeapTupleIsValid(tuple))`
`4468`	`4468`	`{`
`4469`		`- Oid typid;`
`4470`		`- int32 typmod;`
`4471`	`4469`	`float4 *numbers;`
`4472`	`4470`	`int nnumbers;`
`4473`	`4471`
`4474`		`- /* XXX this code would break with different storage type */`
`4475`		`- get_atttypetypmod(relid, colnum, &typid, &typmod);`
`4476`		`-`
`4477`		`- if (get_attstatsslot(tuple, typid, typmod,`
	`4472`	`+ if (get_attstatsslot(tuple, InvalidOid, 0,`
`4478`	`4473`	`STATISTIC_KIND_CORRELATION,`
`4479`	`4474`	`index->ordering[0],`
`4480`	`4475`	`NULL, NULL, &numbers, &nnumbers))`
`@@ -4489,7 +4484,7 @@ btcostestimate(PG_FUNCTION_ARGS)`
`4489`	`4484`	`else`
`4490`	`4485`	`*indexCorrelation = varCorrelation;`
`4491`	`4486`
`4492`		`- free_attstatsslot(typid, NULL, 0, numbers, nnumbers);`
	`4487`	`+ free_attstatsslot(InvalidOid, NULL, 0, numbers, nnumbers);`
`4493`	`4488`	`}`
`4494`	`4489`	`ReleaseSysCache(tuple);`
`4495`	`4490`	`}`