Add note that LIMIT without ORDER BY can produce outright nondeterministic

results.  Necessary due to introduction of syncscan patch.
This commit is contained in:
Tom Lane 2007-06-08 20:26:18 +00:00
parent a3e3389913
commit 4213e5f0db

View File

@ -1,5 +1,5 @@
<!--
$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.100 2007/05/15 19:13:55 neilc Exp $
$PostgreSQL: pgsql/doc/src/sgml/ref/select.sgml,v 1.101 2007/06/08 20:26:18 tgl Exp $
PostgreSQL documentation
-->
@ -810,6 +810,14 @@ OFFSET <replaceable class="parameter">start</replaceable>
to deliver the results of a query in any particular order unless
<literal>ORDER BY</> is used to constrain the order.
</para>
<para>
It is even possible for repeated executions of the same <literal>LIMIT</>
query to return different subsets of the rows of a table, if there
is not an <literal>ORDER BY</> to enforce selection of a deterministic
subset. Again, this is not a bug; determinism of the results is
simply not guaranteed in such a case.
</para>
</refsect2>
<refsect2 id="SQL-FOR-UPDATE-SHARE">