diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/FAQ/TODO.html | 4 | ||||
| -rw-r--r-- | doc/src/sgml/runtime.sgml | 26 |
2 files changed, 15 insertions, 15 deletions
diff --git a/doc/src/FAQ/TODO.html b/doc/src/FAQ/TODO.html index a2b70a78bc9..edd160c3f77 100644 --- a/doc/src/FAQ/TODO.html +++ b/doc/src/FAQ/TODO.html @@ -355,7 +355,7 @@ first. </p> </li><li>Add GUC to issue notice about queries that use unjoined tables </li><li>Allow EXPLAIN to identify tables that were skipped because of - enable_constraint_exclusion + constraint_exclusion </li><li>Allow EXPLAIN output to be more easily processed by scripts </li><li>CREATE <ul> @@ -694,7 +694,7 @@ first. </li><li>Allow the creation of indexes with mixed ascending/descending specifiers </li><li>-<em>Fix incorrect rtree results due to wrong assumptions about "over"</em> operator semantics - </li><li>Allow enable_constraint_exclusion to work for UNIONs like it does for + </li><li>Allow constraint_exclusion to work for UNIONs like it does for inheritance, and allow it to work for UPDATE and DELETE queries </li><li>GIST <ul> diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml index 0966b5105e5..a699e0096b2 100644 --- a/doc/src/sgml/runtime.sgml +++ b/doc/src/sgml/runtime.sgml @@ -1,5 +1,5 @@ <!-- -$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.346 2005/08/21 03:39:26 tgl Exp $ +$PostgreSQL: pgsql/doc/src/sgml/runtime.sgml,v 1.347 2005/08/22 17:34:56 momjian Exp $ --> <chapter Id="runtime"> @@ -2352,24 +2352,24 @@ archive_command = 'copy "%p" /mnt/server/archivedir/"%f"' # Windows </listitem> </varlistentry> - <varlistentry id="guc-enable-constraint-exclusion" xreflabel="enable_constraint_exclusion"> - <term><varname>enable_constraint_exclusion</varname> (<type>boolean</type>)</term> + <varlistentry id="guc-constraint-exclusion" xreflabel="constraint_exclusion"> + <term><varname>constraint_exclusion</varname> (<type>boolean</type>)</term> <indexterm> <primary>constraint exclusion</primary> </indexterm> <indexterm> - <primary><varname>enable_constraint_exclusion</> configuration parameter</primary> + <primary><varname>constraint_exclusion</> configuration parameter</primary> </indexterm> <listitem> <para> - Enables or disables the query planner's use of table constraints. - The default is <literal>off</>. + Enables or disables the query planner's use of table constraints to + limit table access. The default is <literal>off</>. </para> <para> When this parameter is <literal>on</>, the planner compares query - conditions to table CHECK constraints, and omits scanning tables - for which the conditions contradict the constraints. (Presently + conditions with table CHECK constraints, and omits scanning tables + where the conditions contradict the constraints. (Presently this is done only for child tables of inheritance scans.) For example: @@ -2387,15 +2387,15 @@ SELECT * FROM parent WHERE key = 2400; </para> <para> - Currently, <varname>enable_constraint_exclusion</> defaults to - <literal>off</>, because it creates a risk of wrong answers when - query plans are cached: if a table constraint is changed or dropped, - the previously generated plan may now be wrong, and there is no + Currently, <varname>constraint_exclusion</> defaults to + <literal>off</>, because it risks incorrect results if + query plans are cached --- if a table constraint is changed or dropped, + the previously generated plan might now be wrong, and there is no built-in mechanism to force re-planning. (This deficiency will probably be addressed in a future <productname>PostgreSQL</productname> release.) Another reason for keeping it off is that the constraint checks are relatively - expensive to make, and in many circumstances will yield no savings. + expensive, and in many circumstances will yield no savings. It is recommended to turn this on only if you are actually using partitioned tables designed to take advantage of the feature. </para> |