diff options
| -rw-r--r-- | doc/src/sgml/indices.sgml | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/doc/src/sgml/indices.sgml b/doc/src/sgml/indices.sgml index 223bb81cfc8..5d4ecb6a2a1 100644 --- a/doc/src/sgml/indices.sgml +++ b/doc/src/sgml/indices.sgml @@ -1,4 +1,4 @@ -<!-- $PostgreSQL: pgsql/doc/src/sgml/indices.sgml,v 1.58 2006/08/25 04:06:44 tgl Exp $ --> +<!-- $PostgreSQL: pgsql/doc/src/sgml/indices.sgml,v 1.59 2006/09/04 19:58:02 momjian Exp $ --> <chapter id="indexes"> <title id="indexes-title">Indexes</title> @@ -679,7 +679,12 @@ SELECT * FROM orders WHERE order_nr = 3501; <quote>x < 1</quote> implies <quote>x < 2</quote>; otherwise the predicate condition must exactly match part of the query's <literal>WHERE</> condition - or the index will not be recognized to be usable. + or the index will not be recognized to be usable. Matching takes + place at query planning time, not at run time. As a result, + parameterized query clauses will not work with a partial index. For + example a prepared query with a parameter might specify + <quote>x < ?</quote> which will never imply + <quote>x < 2</quote> for all possible values of the parameter. </para> <para> |