From: Bruce Momjian Date: Thu, 19 Jan 2006 22:52:20 +0000 (+0000) Subject: Clarify STABLE function documentation to highlight how such functions X-Git-Tag: REL8_1_3~38 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b148ce8a4a1e24cefdb5f376c0e600ad0401ae47;p=postgresql Clarify STABLE function documentation to highlight how such functions can be optimized. --- diff --git a/doc/src/sgml/xfunc.sgml b/doc/src/sgml/xfunc.sgml index ff461884db..d11e32bc4c 100644 --- a/doc/src/sgml/xfunc.sgml +++ b/doc/src/sgml/xfunc.sgml @@ -1,5 +1,5 @@ @@ -899,13 +899,13 @@ CREATE FUNCTION test(int, int) RETURNS int A STABLE function cannot modify the database and is guaranteed to return the same results given the same arguments - for all calls within a single surrounding query. This category - allows the optimizer to optimize away multiple calls of the function - within a single query. In particular, it is safe to use an expression - containing such a function in an index scan condition. (Since an - index scan will evaluate the comparison value only once, not once at - each row, it is not valid to use a VOLATILE function in - an index scan condition.) + for all rows within a single statement. This category allows the + optimizer to optimize multiple calls of the function to a single + call. In particular, it is safe to use an expression containing + such a function in an index scan condition. (Since an index scan + will evaluate the comparison value only once, not once at each + row, it is not valid to use a VOLATILE function in an + index scan condition.)