Dept of second thoughts: the IQ of estimate_array_length() needs to be

tglsfdc · tglsfdc · commit a053437d9ee7 · 2007-01-28T02:53:34.000Z
kept on par with that of scalararraysel(), else estimates that should
track might not.  Hence teach it about binary-compatible cases, too.
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 1.222 2007/01/28 01:37:38 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.223 2007/01/28 02:53:34 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -1698,6 +1698,9 @@ scalararraysel(PlannerInfo *root,
 int
 estimate_array_length(Node *arrayexpr)
 {
+	/* look through any binary-compatible relabeling of arrayexpr */
+	arrayexpr = strip_array_coercion(arrayexpr);
+
 	if (arrayexpr && IsA(arrayexpr, Const))
 	{
 		Datum		arraydatum = ((Const *) arrayexpr)->constvalue;

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 1.222 2007/01/28 01:37:38 tgl Exp $`
	`18`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/selfuncs.c,v 1.223 2007/01/28 02:53:34 tgl Exp $`
`19`	`19`	`*`
`20`	`20`	`*-------------------------------------------------------------------------`
`21`	`21`	`*/`
`@@ -1698,6 +1698,9 @@ scalararraysel(PlannerInfo *root,`
`1698`	`1698`	`int`
`1699`	`1699`	`estimate_array_length(Node *arrayexpr)`
`1700`	`1700`	`{`
	`1701`	`+ /* look through any binary-compatible relabeling of arrayexpr */`
	`1702`	`+ arrayexpr = strip_array_coercion(arrayexpr);`
	`1703`	`+`
`1701`	`1704`	`if (arrayexpr && IsA(arrayexpr, Const))`
`1702`	`1705`	`{`
`1703`	`1706`	`Datum arraydatum = ((Const *) arrayexpr)->constvalue;`