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Home -> Community -> Mailing Lists -> Oracle-L -> RE: 8.1.7.2.5 interMedia Text Slow Sync - SOLVED
For what seems to be the few of you who use interMedia Text, I found the problem - it was ME. :-(
I had set (in CTX_Parameters) Max_Index_Memory to 200MB (from the default of 12.5MB) and used 200MB when I created indexes, but had overlooked Default_Index_Memory (default of 12.5MB), which is used by CTX_DDL.Sync_Index.
After I set Default_Index_Memory to 200MB, re-syncs jumped from about 750 CLOBs per minute to over 2,500 per minute. Oracle was able to sort an entire batch of 157,000 CLOBs in memory, instead of only about 8,000 at a time - surprise, surprise with 16 times the memory available.
BTW, it didn't hurt that I spread the datafiles of the tablespaces that hold the DR$<>$X segments across 2 drives, instead of just 1. That boosted re-syncs from 600 CLOBs per minute to 750. I/O distribution never hurts.
Jack
-----Original Message-----
Applewhite
Sent: Thursday, January 24, 2002 9:35 AM
To: Multiple recipients of list ORACLE-L
We are experiencing very slow interMedia Text resyncs ( CTX_DDL.Sync_Index ) under 8.1.7.2.5 on Win2k Server.
We upgraded from 8.1.6.0.0 to 8.1.7.2.5 earlier this month (both under Win2k Server) on essentially the same hardware. We used to see about 700-2000 CLOB documents per second indexed under 8.1.6, but now see only about 400-800. The low-high numbers relate to the size of the index being sync'd - low just before we roll out a monthly partition (total 2 million CLOBs), high just after (total 1 million CLOBs).
Query performance is better under 8.1.7 - partly because I spread the DR$<>$I table across 3 drives. By the looks of the I/O pattern, I should spread DR$<>$X (the index on DR$<>$I table) across 2 or 3 drives as well.
Anybody have any words of wisdom as to what I can do to speed things up?
BTW, I'm curious at how 8.1.7 balances I/O. While it's writing to the DR$<>$X segment, it doesn't write to the online redo logs - it waits until it's reading from DR$<>$X segment before it writes to the redo logs. I wonder why it doesn't do the writes to redo in parallel with the writes to DR$<>$X.
Thanks.
Jack
-- Please see the official ORACLE-L FAQ: http://www.orafaq.com -- Author: Jack C. Applewhite INET: japplewhite_at_inetprofit.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_at_fatcity.com (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-LReceived on Thu Jan 31 2002 - 09:42:44 CST
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