Got to a blevel of 20. There is rumored to be hard limit of 23 levels on a b*tree index as implemented by Oracle, maybe I will give that a try later. 05:00:09 rsysdevdb.radisys.com - jkstill@dv03 SQL> set echo on 05:00:13 rsysdevdb.radisys.com - jkstill@dv03 SQL> @r 05:00:14 rsysdevdb.radisys.com - jkstill@dv03 SQL> 05:00:14 rsysdevdb.radisys.com - jkstill@dv03 SQL> select count(*) from t; COUNT(*) ---------- 289810 1 row selected. 05:00:38 rsysdevdb.radisys.com - jkstill@dv03 SQL> 05:00:38 rsysdevdb.radisys.com - jkstill@dv03 SQL> select height 05:00:38 2 , name 05:00:38 3 , blocks 05:00:38 4 , br_blks 05:00:38 5 , br_rows 05:00:38 6 , distinct_keys 05:00:38 7 from index_stats 05:00:38 8 / HEIGHT NAME BLOCKS BR_BLKS BR_ROWS DISTINCT_KEYS ---------- ------ ---------- ---------- ---------- ------------- 20 TIDX 580096 289821 289809 18059 1 row selected. 05:00:38 rsysdevdb.radisys.com - jkstill@dv03 SQL> "Richard Foote" <richard.foote@xxxxxxxxxxx> Sent by: oracle-l-bounce@xxxxxxxxxxxxx 03/10/2004 02:31 PM Please respond to oracle-l To: <oracle-l@xxxxxxxxxxxxx> cc: Subject: Re: Maximum height of an Oracle B-tree index Hi Jared/Tin and all, I believe that was precisely how Steve managed it, very small block size, large pctfree, a bit of cleverness and heaps of storage (until it ran out). He mentioned it btw at the Hotsos tuning class in Sydney last year. So far the best I've heard privately is height of 6. Can anyone do better ? Cheers Richard ----- Original Message ----- From: Jared.Still@xxxxxxxxxxx To: oracle-l@xxxxxxxxxxxxx Sent: Thursday, March 11, 2004 6:46 AM Subject: Re: Maximum height of an Oracle B-tree index My thoughts mirrored Tims. Though after seeing Jonathan Lewis force a very small index to a blevel of 3 with the clever use of data and storage parms and who knows what else, I decided there was a distinct possibility that I was wrong. I've refrained from asking Steve how he did this, but if I see him at dinner this evening, I will find out and report back. :) Jared Live from HOTSOS Tim Gorman <tim@xxxxxxxxxxxxx> Sent by: oracle-l-bounce@xxxxxxxxxxxxx 03/10/2004 06:08 AM Please respond to oracle-l To: <oracle-l@xxxxxxxxxxxxx> cc: Subject: Re: Maximum height of an Oracle B-tree index It would take a heckuva lot of space, even with DB_BLOCK_SIZE = 512 and PCTFREE=99 on the index, to get BLEVEL over 10... Hat's off to Steve on getting it to 20+... on 3/9/04 7:18 AM, Richard Foote at richard.foote@xxxxxxxxxxx wrote: > Hi All, > > I'm currently writing a rather detailed paper for our local user group on > Index Internals, tentatively titled "Index Internals - Rebuilding The > Truth". I haven't had this much fun with tree and block dumps for quite a > while ;) > > One of the many myths I'm exposing is the "rebuild if index has more than 2, > 3, 4, 42, whatever levels". Now to get an honary mention in the paper (what > more reward can one wish for !!), I would love to know who on the list has > created an index with the greatest height and perhaps a little info on it's > circumstance. > > Steve Adams once mentioned to me creating an index with 20+ levels, can > anyone else come close ? > > Thanks for any replies. > > Richard > > > ---------------------------------------------------------------- > Please see the official ORACLE-L FAQ: http://www.orafaq.com > ---------------------------------------------------------------- > To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx > put 'unsubscribe' in the subject line. > -- > Archives are at //www.freelists.org/archives/oracle-l/ > FAQ is at //www.freelists.org/help/fom-serve/cache/1.html > ----------------------------------------------------------------- ---------------------------------------------------------------- Please see the official ORACLE-L FAQ: http://www.orafaq.com ---------------------------------------------------------------- To unsubscribe send email to: oracle-l-request@xxxxxxxxxxxxx put 'unsubscribe' in the subject line. -- Archives are at //www.freelists.org/archives/oracle-l/ FAQ is at //www.freelists.org/help/fom-serve/cache/1.html -----------------------------------------------------------------