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 issue with performance

Author  Topic 

zaty2405
Yak Posting Veteran

58 Posts

Posted - 2010-06-16 : 18:56:41
Hi,

After I rebuild the user database index , i found that the transaction response time are longer that before .

How do I checked what actually caused this? I did run the update statistics after the rebuild.

Another question, what actually happen when sql services were restarted. Does it impact anything?
Thanks

sodeep
Master Smack Fu Yak Hacker

7174 Posts

Posted - 2010-06-16 : 19:08:53
If you have rebuild the index then you don't need to update statistics. Also You shouldn't rebuild index in productivity time as it is offline operations unless you are using ONLINE Operation.If Sql server is restarted,that means all cache was flushed,this will slow down performance.
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zaty2405
Yak Posting Veteran

58 Posts

Posted - 2010-06-16 : 19:21:47
Thanks Sodeep..
Is there anyway to ensure certain query plan stay in cache?
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Kristen
Test

22859 Posts

Posted - 2010-06-17 : 02:38:08
Don't think so.

You could launch a query after restart to re-generate the query plan in cache?

(There is a "Service Start" event you can hook to perform tasks like that)
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GilaMonster
Master Smack Fu Yak Hacker

4507 Posts

Posted - 2010-06-17 : 05:31:25
Query plans are memory only, so a restart of SQL will result in an empty plan (and data) cache. Short of running queries right after startup to warm the cache, there's nothing you can really do about that

--
Gail Shaw
SQL Server MVP
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zaty2405
Yak Posting Veteran

58 Posts

Posted - 2010-06-17 : 06:38:33
Thanks Gail & Kristen.

Since restarting SQL server services flushed out the execution plans , is there a way to force the execution plan to stay in memory?

Thanks
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GilaMonster
Master Smack Fu Yak Hacker

4507 Posts

Posted - 2010-06-17 : 08:19:48
No. SQL will keep them in cache if it can, but there are lots of things that will result in a plan being discarded. Stats changes, schema changes, explicit recompile requests, memory pressure, some server configuration changes, some database maintenance tasks, index rebuilds, couple more.

--
Gail Shaw
SQL Server MVP
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