Add more info on regex's using INDEX.

1 files changed, 15 insertions, 5 deletions

diff --git a/doc/FAQ b/doc/FAQ
index 0cc05b3d3b7..9c2f01a3e53 100644
--- a/doc/FAQ
+++ b/doc/FAQ
@@ -1,7 +1,7 @@
 
                 Frequently Asked Questions (FAQ) for PostgreSQL
                                        
-   Last updated: Mon Jun 24 21:45:50 EDT 2002
+   Last updated: Mon Jun 24 23:32:16 EDT 2002
    
    Current maintainer: Bruce Momjian (pgman@candle.pha.pa.us)
    
@@ -747,10 +747,20 @@
     LIMIT 1
 
    When using wild-card operators such as LIKE or ~, indexes can only be
-   used if the default C local is used during initdb and the beginning of
-   the search is anchored to the start of the string. Therefore, to use
-   indexes, LIKE patterns must not start with %, and ~(regular
-   expression) patterns must start with ^.
+   used in certain circumstances:
+     * The beginning of the search string must be anchored to the start
+       of the string, i.e.:
+       
+     * LIKE patterns must not start with %.
+     * ~(regular expression) patterns must start with ^.
+       
+     The search string can not start with a character class, e.g. [a-e].
+   
+     Case-insensitive searches like ILIKE and ~* can not be used.
+   Instead, use functional indexes, which are described later in this
+   FAQ.
+   
+     The default C local must have been used during initdb.
    
     4.9) How do I see how the query optimizer is evaluating my query?