--- [EMAIL PROTECTED] wrote: > > Tom Kyte states that they are never needed, which I don't believe to be > correct.
As I said two weeks ago, somewhere on the Internet people over-trusted authorities. It's different here. I love this place! > I'll try to back this up with data in the future. As a Ph.D in chemistry (sorry to say this), I know how more important repeated experiments done by different people in different labs are than theory. Furthermore, a lab experiment is nothing if a product coming out of a chemical plant says no good. > So if Tom asks any of you why you don't use automatic space management in > your LMT's, you can ask him why he doesn't use 'alter index rebuild'. ;) > > Jared > > > > > > > Yong Huang <[EMAIL PROTECTED]> > Sent by: [EMAIL PROTECTED] > 11/06/2003 02:59 PM > Please respond to ORACLE-L > > > To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> > cc: > Subject: Re: any problem rebuilding indexes used for > replication > > > renu (and Jared), > > The reason I'm very interested in whether there's performance improvement > is > that there's a thread on the newsgroup about index rebuild recently. See > > http://groups.google.com/groups?threadm=pan.2003.11.03.08.09.24.330520%40RE-MO-VE.BountifulSolutions.co.uk > > Jonathan Lewis says there's almost no need to rebuild indexes, although > his > "Practical Oracle8i" lists at least one case you may benefit by > rebuilding. (I > don't have the book with me). Asktom.oracle.com has numerous messages > advising > against rebuilding indexes. Let's set theory aside for a moment and do the > experiment. Please post your report of performance change. Thanks. > > Yong Huang > > --- renu r <[EMAIL PROTECTED]> wrote: > > Jared : I think it is fragmented based on scripts and knowing that there > have > > been lot of deletes. > > > > One script uses the table index_stats and looks at field del_lf_rows > which > > should be less at least in comparison to field lf_rows. I mean less is > good. > > more bad. I am not sure about the script but I will post it here if > someone > > says so or send it to anyone if they want. > > > > I am sure the experts here know about it and can clarify if it is any > good > > to look at the index_stats table. > > > > One other simple useful script is : > > > > SELECT owner, index_name, blevel > > FROM all_indexes > > WHERE blevel > 2 > > > > This can be bacause the size of table is big so it is not definitive. I > will > > check the level after rebuild. > > > > Benefits expected : Space savings (definitely). performance (hopefully). > I > > will let you and Yong know about the benefits if any. If I get some > help. > > > > > > [EMAIL PROTECTED] wrote: > > > > I'm curious, how have you identified the fragmentation? > > > > What benefits do you expect from the rebuild of the indexes? > > > > Are you targeting certain indexes that have been identified as > > benefiting from a rebuild, or just planning to rebuild all indexes? > > > > Jared > > > > > > > > > > renu r <[EMAIL PROTECTED]> > > Sent by: [EMAIL PROTECTED] > > 11/05/2003 06:14 PM > > Please respond to ORACLE-L > > > > > > To: Multiple recipients of list ORACLE-L > > <[EMAIL PROTECTED]> > > cc: > > Subject: any problem rebuilding indexes used for > replication > > > > > > Hello, > > I have to rebuild some primary key indexes due to excessive > fragmentation. > > It is rebuild not drop and create. We have multi master replication > running. > > Is there any problem to replication if I do that. Has anyone tried it? > TIA. __________________________________ Do you Yahoo!? Protect your identity with Yahoo! Mail AddressGuard http://antispam.yahoo.com/whatsnewfree -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Yong Huang INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (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).
