Home » RDBMS Server » Performance Tuning » FLUSH SHARED_POOL (Oracle,10.2.4.0,linux)
FLUSH SHARED_POOL [message #422982] Mon, 21 September 2009 10:20 Go to next message
sundarfaq
Messages: 235
Registered: October 2007
Location: Chennai
Senior Member
hI,

I have execueted the below statements

ALTER SYSTEM FLUSH SHARED_POOL

after executing, the query was very very slow.

how we will revert the FLUSH SHARED_POOL?

Please help me..

thanks,
Michael
Re: FLUSH SHARED_POOL [message #422983 is a reply to message #422982] Mon, 21 September 2009 10:25 Go to previous messageGo to next message
BlackSwan
Messages: 24914
Registered: January 2009
Senior Member
>how we will revert the FLUSH SHARED_POOL?
No way. Things will be better tomorrow; unless you do it again.
Re: FLUSH SHARED_POOL [message #422987 is a reply to message #422982] Mon, 21 September 2009 10:41 Go to previous messageGo to next message
sundarfaq
Messages: 235
Registered: October 2007
Location: Chennai
Senior Member
i don't understand.. please explain clearly.
Re: FLUSH SHARED_POOL [message #422988 is a reply to message #422987] Mon, 21 September 2009 10:54 Go to previous messageGo to next message
BlackSwan
Messages: 24914
Registered: January 2009
Senior Member
Imagine you are on a moving train & holding a trash can & empty the can by dumping the contents outside the train.
The above is equivalent to FLUSH SHARED POOL.
Only time and using the application will repopulate Shared Pool.
Re: FLUSH SHARED_POOL [message #423002 is a reply to message #422982] Mon, 21 September 2009 13:17 Go to previous messageGo to next message
Bill B
Messages: 1458
Registered: December 2004
Senior Member
I have never had a valid reason in 25 years to flush the shared pool except when I just had to try it and then i did it on test. Oracle will handle the pool quite nicely and the result of flushing (normally) is a very slow server until the pool is rebuilt from usage of the database.
Re: FLUSH SHARED_POOL [message #423110 is a reply to message #422982] Tue, 22 September 2009 03:33 Go to previous message
bishtoo
Messages: 20
Registered: August 2009
Junior Member
shared pool helps in performance boost since it has shared sql area which keeps info about recently executed SQLs..
So same sqls are not parsed again and again..thus saving precious time in execution..so once you flushed shared pool it will be empty and there will be nothing like sql parsed info of previous SQls..

In your case, oracle will again populate shred sql and performance will come to normal..
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