From Riyaj_Shamsudeen@i2.com Fri, 07 Sep 2001 07:32:59 -0700 From: Riyaj_Shamsudeen@i2.com Date: Fri, 07 Sep 2001 07:32:59 -0700 Subject: Re: Fast Full Index Scan in 8.1.7 In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: text/plain Cherie                 You could turn it off using _fast_full_scan_enabled=false at the instance level. fast_full_scan_enabled is simply an underscore parameter in 8.1.7. But, I would turn on the event 10053 and run the statement to find why CBO is not using.. Could it be possible that this behaviour is due to poor index selectivity ?         alter session set events '10053 trace name context forever, level 1'; Thanks Riyaj "Re-yas" Shamsudeen Certified Oracle DBA i2 technologies   www.i2.com Cherie_Machler@gelco.com Sent by: root@fatcity.com 09/07/01 06:55 AM Please respond to ORACLE-L                 To:        Multiple recipients of list ORACLE-L         cc:                 Subject:        Re: Fast Full Index Scan in 8.1.7 I wanted to turn it off in testing so I could try some other indexes as an alternative.   I'm not sure that I trust it to make a good decision. Even with an alternative index hint, it's not using the index I'm trying to get it to use, but rather the fast full index scan.  I can't see any typo but maybe it just can't use that index with full full index scan enabled. That's why I wanted to try and disable it and see what would happen. CBO does some interesting things.  Every time I think I have a handle on some aspect of it, it changes and starts doing something different. Thanks for your reply. Cherie                                                                                                                                      Jared Still                                                                                                                       cc:                                                                                                               Subject:     Re: Fast Full Index Scan in 8.1.7                                                09/07/01 12:04                                                                                                    AM                                                                                                                                                                                                                                                                                                                                 The alternative is probably a full table scan. Are you sure you want to turn it off? I think you need to hint your SQL to do that. Jared On Thursday 06 September 2001 13:21, Cherie_Machler@gelco.com wrote: > I had been using the FAST_FULL_SCAN_ENABLED initialization parameter in an > 8.0.4 database. > > Apparently this parameter is now obsolete in 8.1.7.2.   Seems as though I > am getting the fast full index > scans automatically now.  I'm not sure if I want them in all cases.   Is > there a way to turn them off? > > Thanks, > > Cherie Machler > Oracle DBA > Gelco Information Network -- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author:  INET: Cherie_Machler@gelco.com Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051 San Diego, California        -- Public Internet access / Mailing Lists -------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: ListGuru@fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from).  You may also send the HELP command for other information (like subscribing).