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SGA size [message #170428] Wed, 03 May 2006 14:59 Go to next message
Daxesh
Messages: 61
Registered: July 2004
Member
Hello there,

I have three databases, I think I have set up really high SGA for those. I would like to reduce that. So could somebody please tell me step by step process to reduce SGA for those databases?

Any input would be greatly appreciated.
Thanks again,

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Re: SGA size [message #170441 is a reply to message #170428] Wed, 03 May 2006 20:48 Go to previous messageGo to next message
BlackSwan
Messages: 26766
Registered: January 2009
Location: SoCal
Senior Member
>I think I have set up really high SGA for those.
Based upon which metrics did you reach this conclusion?

>I would like to reduce that.
What benefit do you expect to achive from doing so?

To make the SGA smaller, reduce the appropriate values in the initSID.ora file.

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Re: SGA size [message #170575 is a reply to message #170441] Thu, 04 May 2006 07:15 Go to previous messageGo to next message
Daxesh
Messages: 61
Registered: July 2004
Member
Thanks for your reply. But can you tell me which parameter(s) value I need to reduce in initSID.ora file?

Thanks

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Re: SGA size [message #170631 is a reply to message #170575] Thu, 04 May 2006 09:51 Go to previous messageGo to next message
lakher
Messages: 14
Registered: April 2006
Junior Member
db_cache_size
shared_pool_size

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Re: SGA size [message #170636 is a reply to message #170631] Thu, 04 May 2006 10:09 Go to previous messageGo to next message
JSI2001
Messages: 1016
Registered: March 2005
Location: Scotland
Senior Member
@lakher
how do you arrive at the conclusion, based on the information currently provided, that it is the db_cache and shared pool that need to be resized. I'm dying to know this.
Jim

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Re: SGA size [message #170641 is a reply to message #170636] Thu, 04 May 2006 10:18 Go to previous messageGo to next message
lakher
Messages: 14
Registered: April 2006
Junior Member
to reduce sga smaller，the first step reduce consist of sga that db cache and share pool size，and then reduce sga size

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Re: SGA size [message #170642 is a reply to message #170641] Thu, 04 May 2006 10:21 Go to previous messageGo to next message
JSI2001
Messages: 1016
Registered: March 2005
Location: Scotland
Senior Member
really? what about an unused large_pool, what about the java pool, what if they're too big but the shared pool is too small? reducing the shared pool will simply compound the issues. My point is that there is absolutely no way to show that your solution would work (or is even necessary) based on the info that the op provided.

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Re: SGA size [message #170643 is a reply to message #170642] Thu, 04 May 2006 10:38 Go to previous messageGo to next message
lakher
Messages: 14
Registered: April 2006
Junior Member
oh，i think it is too simple，
i only tell him which parameters to reduce。but really reduce sga size ，it must consider application in fact.example you said large pool,java pool.
thanks JSI2001。

[Updated on: Thu, 04 May 2006 10:40]

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Re: SGA size [message #170648 is a reply to message #170428] Thu, 04 May 2006 11:20 Go to previous messageGo to next message
Daxesh
Messages: 61
Registered: July 2004
Member
Thanks both of you. Looks like you both know what needs to be done to reduce SGA, Can somebody please tell me step by step process.

Thanks,

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Re: SGA size [message #170775 is a reply to message #170648] Fri, 05 May 2006 02:21 Go to previous message
JSI2001
Messages: 1016
Registered: March 2005
Location: Scotland
Senior Member
Step 1. Read the documentation.
You can download it at http://tahiti.oracle.com.
Start with the concepts guide. Move onto Admin guide. For additional info you can buy Tom Kyte's Expert 1 on 1, and Effective Oracle by Design (you'll find them both at Amazon.co.uk)
I strongly suggest that you do at least some reasearch, particularly the concepts guide before you do any resizing of your memory structures.
http://asktom.oracle.com/pls/ask/f?p=4950:8:14122976973231345843::NO::F4950_P8_DISPLAYID,F4950_P8_CRITERIA:8759826405304
Here is a good link that points out some of the things that you need to consider.

HTH
Jim

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