Update EXPLAIN wording for GEQO usage.

diff --git a/doc/src/sgml/ref/explain.sgml b/doc/src/sgml/ref/explain.sgml
index a3b607cd8b17ec3c5311f9f1553b07e09315c049..27407fe958c42761461e3cb600d80fdb14fb677a 100644 (file)
--- a/doc/src/sgml/ref/explain.sgml
+++ b/doc/src/sgml/ref/explain.sgml
@@ -150,6 +150,14 @@ ROLLBACK;
    the query, and consequently an inferior query plan may be chosen.
   </para>
 
+  <para>
+   Genetic query optimization (<acronym>GEQO</acronym>) randomly 
+   tests execution plans.  Therefore, when the number of tables exceeds
+   <varname>geqo_threshold</> causing genetic query optimization to be 
+   used, the execution plan is likely to change each time the statement
+   is executed.
+  </para>
+
   <para>
    Prior to <productname>PostgreSQL</productname> 7.3, the plan was
    emitted in the form of a <literal>NOTICE</literal> message.  Now it