No Dave, youre right, as I mentioned, index changes will always log. Only option there is to mark unusable, load table, then rebuild w/ = nologging. Jonathan, you're right of course, I saw APPEND and immediately assumeed = NOLOGGING, but that's not the case. At least, the original poster didn't mention NOLOGGING. Harvinder, Allow me to summarize: For optimal insert performance 1.) alter table ... nologging 2.) alter index ... unusable for each index on the table 3.) alter session set skip_unusable_indexes=3Dtrue 4.) INSERT /*+ APPEND */ from one session and commit 5.) rebuild all indexes w/ nologging That will generate minimal redo and undo on the table inserts as well as = the=20 index rebuilds. Note however, the recovery implications if you utilize=20 nologging. You'll need a backup of the tablespace your table is in. = Since=20 there was no data written to the redo log (except extent invalidation = records) there's no way to recover that data in the event of a media failure. Hope I didn't overlook or omit anything that time.... -Mark -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of David Kurtz Sent: Fri 6/18/2004 6:03 PM To: oracle-l@xxxxxxxxxxxxx Cc:=09 Subject: RE: Question about Append hint in Insert But if the table has an index, and even if you use the NOLOGGING hint = (and create the table and index NOLOGGING too) it appears that you still generate redo when maintaining the index. The only way I have found to avoid redo on the index is to populate the table and then build the index NOLOGGING. (am I missing anything?) Attached is a simple test script and my output on 9.2.0.5. _________________________ David Kurtz -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of Jonathan Lewis Sent: 18 June 2004 22:33 To: oracle-l@xxxxxxxxxxxxx Subject: Re: Question about Append hint in Insert Mark, APPEND stops table UNDO, not table REDO. That point often gets hidden because the hint is used so often in conjunction with nologging tables. Otherwise your comments are correct - the benefit applies only to the table segment, and you get the exclusive table lock. There is some potential for benefit on the indexes because the index entries are per-sorted before inserting, and there is an optimization that reduces undo and redo if multiple rows goes into a single leaf block. There is some downside on the table because the HWM is bumped for the append, so you could leave a trail of empty space behind you as you do lots of appends - but at 1,000 rows per insert, the percentage waste of space is likely to be small. Regards Jonathan Lewis http://www.jlcomp.demon.co.uk http://www.jlcomp.demon.co.uk/faq/ind_faq.html The Co-operative Oracle Users' FAQ http://www.jlcomp.demon.co.uk/seminar.html Optimising Oracle Seminar - schedule updated May 1st ----- Original Message ----- From: "Bobak, Mark" <Mark.Bobak@xxxxxxxxxxxxxxx> To: <oracle-l@xxxxxxxxxxxxx> Sent: Friday, June 18, 2004 8:06 PM Subject: RE: Question about Append hint in Insert Harvinder, 1.) Should be no real disadvantage, other than an exclusive lock on the table. More on that later. 2.) Hint will only apply to table. Any index updates that result from table load will always log. If you want to, you could alter index ... unusable, then do the load, then alter index ... rebuild nologging; 3.) The problem here is that an INSERT /*+ APPEND */ takes an *exclusive* lock on the table. This prevents any other DML from running on the table till that transaction commits. The second process will wait on the exclusive mode TM enqueue that the first process is holding. Hope that helps, -Mark Mark J. Bobak Oracle DBA ProQuest Company Ann Arbor, MI "Post Hoc Ergo Propter Hoc" -----Original Message----- From: oracle-l-bounce@xxxxxxxxxxxxx [mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Harvinder Singh Sent: Friday, June 18, 2004 2:43 PM To: oracle-l@xxxxxxxxxxxxx Subject: Question about Append hint in Insert Hi, We are testing insert performance in one of out tables and we are selecting from 1 table 1000 rows at a time and inserting in 2nd table. So we were getting tps of about 17000 for 1 million records. Then I added append hint to insert and tps went up to 23000. Now if I a try to insert from 2 clients to increase scalibility both insert at tps of 11000. so I have 2 questions: 1) What is the disadvantage of adding append hint during insert (we never delete or update this table in production) 2) Will the hint applicable to all the indexes or only table 3) Why with 2 clients using append result in less tps than normal 2 client inserts? Thanks --Harvinder =3D3D20 ---------------------------------------------------------------- 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 ----------------------------------------------------------------- -- Binary/unsupported file stripped by Ecartis -- -- Type: application/octet-stream -- File: nologdemo.LST -- Attached file included as plaintext by Ecartis -- -- File: nologdemo.sql set echo on head on message on feedback on trimspool on timi off pause = off autotrace off column name format a20 drop table dmk; spool nologdemo clear screen=20 select * from v$version; create table dmk nologging as select * from dba_objects where 1=3D2 ; truncate table dmk; ttitle before-noindex select s.name, s.value sysstat, m.value mystat from v$sysstat s, v$mystat m where s.name =3D 'redo size' and s.statistic# =3D m.statistic# / insert /*+ APPEND NOLOGGING */ into dmk select *=20 from dba_objects where rownum <=3D 1000; commit / ttitle after-noindex select s.name, s.value sysstat, m.value mystat from v$sysstat s, v$mystat m where s.name =3D 'redo size' and s.statistic# =3D m.statistic# / create index dmk on dmk(owner, objecT_name) nologging ; ttitle before+index select s.name, s.value sysstat, m.value mystat from v$sysstat s, v$mystat m where s.name =3D 'redo size' and s.statistic# =3D m.statistic# / insert /*+ APPEND NOLOGGING */ into dmk select *=20 from dba_objects where rownum <=3D 1000; commit / ttitle after+index select s.name, s.value sysstat, m.value mystat from v$sysstat s, v$mystat m where s.name =3D 'redo size' and s.statistic# =3D m.statistic# / spool off drop table dmk; ---------------------------------------------------------------- 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 -----------------------------------------------------------------