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Backpatch of LIMIT / FOR UPDATE behavior, but keep pre-7.3 mention in 8.0.X.

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Bruce Momjian
2005-04-22 15:53:27 +00:00
parent ddae2b6801
commit 8e4b89ccf2
1 changed files with 11 additions and 1 deletions
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12
doc/src/sgml/ref/select.sgml
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@@ -1,5 +1,5 @@
<!-- <!--
$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.80.4.1 2005/01/22 23:23:53 momjian Exp $ $PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.80.4.2 2005/04/22 15:53:27 momjian Exp $
PostgreSQL documentation PostgreSQL documentation
--> -->
@@ -818,6 +818,16 @@ FOR UPDATE [ OF <replaceable class="parameter">table_name</replaceable> [, ...]
rows; for example it can't be used with aggregation. rows; for example it can't be used with aggregation.
</para> </para>
<para>
It is possible for a <command>SELECT</> command using both
<literal>LIMIT</literal> and <literal>FOR UPDATE</literal>
clauses to return fewer rows than specified by <literal>LIMIT</literal>.
This is because <literal>LIMIT</> selects a number of rows,
but might then block requesting a <literal>FOR UPDATE</literal> lock.
Once the <literal>SELECT</> unblocks, the query qualification might not
be met and the row not be returned by <literal>SELECT</>.
</para>
<para> <para>
<literal>FOR UPDATE</literal> may appear before <literal>FOR UPDATE</literal> may appear before
<literal>LIMIT</literal> for compatibility with <literal>LIMIT</literal> for compatibility with