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| -rw-r--r-- | doc/src/sgml/func.sgml | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 4c5af4b83c8..8cf53855616 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -10563,6 +10563,16 @@ SELECT a, SELECT ... WHERE CASE WHEN x <> 0 THEN y/x > 1.5 ELSE false END; </programlisting> </para> + + <note> + <para> + As described in <xref linkend="xfunc-volatility">, functions and + operators marked <literal>IMMUTABLE</literal> can be evaluated when + the query is planned rather than when it is executed. This means + that constant parts of a subexpression that is not evaluated during + query execution might still be evaluated during query planning. + </para> + </note> </sect2> <sect2 id="functions-coalesce-nvl-ifnull"> |