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-$PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.109 2005/11/29 01:46:54 alvherre Exp $
+$PostgreSQL: pgsql/doc/src/sgml/xfunc.sgml,v 1.110 2006/01/19 22:52:08 momjian Exp $
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<sect1 id="xfunc">
<para>
A <literal>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 <literal>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 <literal>VOLATILE</> function in an
+ index scan condition.)
</para>
</listitem>
<listitem>