10G OLAP Performance Tuning

Question

HI if anyone had some tips for tuning 10g, so that my OLAP (AW in particular) performance is at its peak.
THe server specs are as follows:
Server1.
Windows 2000 Server
2GB RAM
Server2.
Windows XP Pro SP1
1GB RAM
I find that when I import old Express 6.3.4 databases into 10g, after import, the initial Update/commit, takes the same time as the import command. Is this because it has to write data from temporary space to permament.
I am basically looking for comparable parameters to that which would have been set in Express Instance Manager.
At this stage I have only looked to tweak :
shared_pool_size
sga_target
db_cache_size
From my reading I understand it is best to leave olap_page_pool_size as 0.
Can any one assist. I am finding that performace using default parameters in 10g, is worse than that of Express 6.3.4.
Regards,
Imran Shah
Ioppolo & Associates
[email protected]

Answer 1

Here are some guidelines for improving the OLAP performance in Oracle Database 10g Release 1.
A. Turn off LOGGING (REDO) during builds to improve data insertion performance.
Disable Logging during build to improve overall load performance. Once load is complete turn it on.
If you choose to set NOLOGGING for the LOB segment (of the AW$ table containing your Analytic Workspace) check out MetaLink 1058851.6 for information pertaining to event 10359 which can reduce I/O for frequently updated NOLOGGING LOBs.
http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=1058851.6
* Turn Logging off prior to commencing build.
ALTER TABLE GLOBAL.AW$GLOBAL MODIFY LOB (awlob) (CACHE READS NOLOGGING);
* Turn Logging on after build completes.
ALTER TABLE GLOBAL.AW$GLOBAL MODIFY LOB (awlob) (CACHE READS LOGGING);
B. Increase REDO Log size and log_buffer parameter to reduce log switch waits and improve overall time.
Ask the DBA to increase this to somewhere between 100M and 500M from the default of 10M. Use ADDM to determine the ideal size.
C. Build Analytic Workspaces (LOBs) in separate preallocated Tablespaces to improve overall data load performance.
This can reduce device contention while preallocating space avoids allocation during inserts and updates.
D. Move TEMP, UNDO and REDO Logs to fastest disks to improve overall build performance.
Ask the DBA to place TEMP, UNDO and REDO Logs on fastest disks. No RAID5. Use RAW whenever possible and consider RAID10 or 0+1. RAID 5 can severely affect performance on highly updated databases.
E. Specify better OLAP DML for SQL IMPORT or SQL INSERT DIRECT to improve analytic workspace load performance.
SQL INSERT DIRECT is up to 53x faster than SQL INSERT.
NOTE: Source tables should be ordered by the inverse of the target object's dimensionality when loading data from relational sources into an analytic workspace.
SQL IMPORT is up to 7x faster than SQL FETCH.
F. Use AW TRUNCATE instead of AW DELETE if you wish to keep the analytic workspace name. Performs better with less overhead.
EXEC DBMS_AW.EXECUTE('AW TRUNCATE SCOTT.EMPAW');
[Edited by: awaite on Apr 20, 2005 11:20 AM]