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coolguy
Beginner
Joined: 01 Dec 2004
Posts: 82
Topics: 28
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 Posted: Tue Nov 21, 2006 6:23 am Post subject: Perfromance Issue |
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I am facing the performance problem In DB2 , actually prev we wew using DB2 version 5 now we have upgrded the verison to Db2 version 7
Now some of the queiries taking long time to run after the upgradtion
pls gimme some idea what the piont we need to check for the performance related things
Thanks
Cool |
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bauer
Intermediate
Joined: 10 Oct 2003
Posts: 315
Topics: 49
Location: Germany
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| Posted: Tue Nov 21, 2006 6:30 am Post subject: |
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coolguy,
- check statistic data in db2 catalog. Are statistic data up to date ?
- Rebind / Bind activitys ?
- Do an explain
- Are the data befor upgrading really the same ? Other table cardinality ?
bauer |
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coolguy
Beginner
Joined: 01 Dec 2004
Posts: 82
Topics: 28
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| Posted: Tue Nov 21, 2006 6:42 am Post subject: |
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I did all the things and Runstats also , i am pretty sure the data's are same,
While using explain it is going for the tablespace scan ,
how to change the things can u help me
Thanks
Cool |
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bauer
Intermediate
Joined: 10 Oct 2003
Posts: 315
Topics: 49
Location: Germany
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| Posted: Tue Nov 21, 2006 7:39 am Post subject: |
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coolguy,
well, why table space scan, this is very poor (for large tables).
I would recommend to create an index if the table space scan is the bottle neck.
bauer |
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rubenprakash
Beginner
Joined: 03 Nov 2006
Posts: 6
Topics: 2
Location: India
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| Posted: Tue Nov 21, 2006 11:47 am Post subject: |
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| coolguy wrote: | I did all the things and Runstats also , i am pretty sure the data's are same,
While using explain it is going for the tablespace scan ,
how to change the things can u help me
Thanks
Cool |
Are you sure that the statistic tables are updated till date? Whether in earlier version of DB2 do the query go for tablespace scan? It should be index scan. If index is not created we need that one if index is already present then need to check the stat tables...
_________________
Regards, Ruben |
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bauer
Intermediate
Joined: 10 Oct 2003
Posts: 315
Topics: 49
Location: Germany
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| Posted: Wed Nov 22, 2006 1:37 am Post subject: |
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coolguy,
other remark: What about reorg ? Are we talking about clusterd index? |
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