| 9.2.0.4 Recent Upgrade AIX using DIO [message #60892] |
Fri, 12 March 2004 03:42  |
ian
Messages: 27
Registered: September 1999
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Junior Member |
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Hi,
after upgrading to 9204 from 8174 and upgrading the Operating System from 32bit to 64bit running AIX 5.2L we now seem to see far greater wait for IO looking at statpsack the Top Wait time has gone from being the normal db file sequential read to CPU Time. The disks are mounted using Direct IO and this is the same as it was for 8i.
9i.
CPU time 60,470 51.53
db file sequential read 5,647,114 34,776 29.63
SQL*Net message from dblink 2,989,392 10,862 9.26
db file scattered read 2,005,409 6,009 5.12
buffer busy waits 365,070 1,195 1.02
8i
db file sequential read 3,585,878 37,250 63.63
CPU time 9,026 15.42
SQL*Net message from dblink 782,414 4,350 7.43
db file parallel write 21,436 1,605 2.74
db file scattered read 427,540 1,529 2.61
I am trying to work out what is working the CPU so much harder?! I also see a much higher time spent in WIO than before.
Any ideas?
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| Re: 9.2.0.4 Recent Upgrade AIX using DIO [message #60894 is a reply to message #60892] |
Fri, 12 March 2004 04:27  |
Thiru
Messages: 1089
Registered: May 2002
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Senior Member |
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Did something else change during the migration ? And you are collecting statistics ,I hope.
Inorder to see if this is got to do with 9i optimizer changes, try setting optimizer_features_enable=8.1.7 and see how its performing. In 9i, a bunch of optimizer related parameters changed and some others have reported a similar problem.
Also you might need to tweak optimizer_index settings to make sure its not going for unnecessary full table scans,although it looks like you are not experiencing much waits on it. Cross check with v$system_event and v$sysstat.
Also try collecting system statistics , to provide the optimizer with details about the system(single block,multiblock read time , cpu cycles etc).
-Thiru
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| Re: 9.2.0.4 Recent Upgrade AIX using DIO [message #60910 is a reply to message #60892] |
Fri, 12 March 2004 09:22 |
Sanjay Bajracharya
Messages: 279
Registered: October 2001
Location: Florida
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Senior Member |
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I also have nearly the same config (9.2.0.4.0 and AIX5.1 ML4)...
I upgraded from 8.1.7.4.0 recently. In fact, I did 2 upgrades:
1. upgrade from Oracle 817 to 920 in AIX 433
2. upgrade from AIX433 to AIX51 with Oracle 920 (new install of Oracle binaries).
The first upgrade itself I saw performance degrade. May be I am not tapping into the right area. The 2nd one is not as bad as the 1st one...but compared to Oracle 817 in AIX433 and Oracle 920 in AIX5L, there is considerable amount of perf difference.
If you have any suggestion, tuning tips .. please pass on.
Thanx.
-
Sanjay
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