Document use of GEQO param in subquery pullups.

diff --git a/doc/src/sgml/runtime.sgml b/doc/src/sgml/runtime.sgml
index b3d68e4006865cb0f757a64c36b830a1c96f94dc..0bb3eb1c44bb7e4fe441e9111efbf6572aed2807 100644 (file)
--- a/doc/src/sgml/runtime.sgml
+++ b/doc/src/sgml/runtime.sgml
@@ -1,5 +1,5 @@
 
 
 
@@ -719,7 +719,9 @@ env PGOPTIONS='-c geqo=off' psql
         this many FROM items involved.  (Note that a JOIN construct
    counts as only one FROM item.) The default is 11. For simpler
    queries it is usually best to use the
-        deterministic, exhaustive planner.
+        deterministic, exhaustive planner.  This parameter also controls
+        how hard the optimizer will try to merge subquery
+        FROM clauses into the upper query.