diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/maintenance.sgml | 10 |
1 files changed, 9 insertions, 1 deletions
diff --git a/doc/src/sgml/maintenance.sgml b/doc/src/sgml/maintenance.sgml index ecec84cc2d9..0b01467ee01 100644 --- a/doc/src/sgml/maintenance.sgml +++ b/doc/src/sgml/maintenance.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.99 2010/02/08 04:33:51 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/maintenance.sgml,v 1.100 2010/02/23 02:47:27 momjian Exp $ --> <chapter id="maintenance"> <title>Routine Database Maintenance Tasks</title> @@ -318,6 +318,14 @@ SET STATISTICS</>, or change the database-wide default using the <xref linkend="guc-default-statistics-target"> configuration parameter. </para> + + <para> + Also, by default there is limited information available about + the selectivity of functions. However, if you create an expression + index that uses a function call, useful statistics will be + gathered about the function, which can greatly improve query + plans that use the expression index. + </para> </tip> </sect2> |