Add section on testing index scan.

diff --git a/doc/FAQ b/doc/FAQ
index 15c5316bb8c5923d67eef310f5a5fede51832c15..78c113de9e0557f17ea974e15d792beba166e190 100644 (file)
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -1,7 +1,7 @@
 
                 Frequently Asked Questions (FAQ) for PostgreSQL
                                        
-   Last updated: Sun Jan 12 13:36:11 EST 2003
+   Last updated: Fri Jan 17 12:15:04 EST 2003
    
    Current maintainer: Bruce Momjian ([email protected])
    
@@ -749,6 +749,10 @@
     ORDER BY col [ DESC ]
     LIMIT 1;
 
+   If you believe the optimizer is incorrect in choosing a sequential
+   scan, use SET enable_seqscan TO 'off' and run tests to see if an index
+   scan is indeed faster.
+   
    When using wild-card operators such as LIKE or ~, indexes can only be
    used in certain circumstances:
      * The beginning of the search string must be anchored to the start