| non standard block size [message #519571] |
Mon, 15 August 2011 00:33  |
zeeshan047
Messages: 99
Registered: June 2010
Location: PAKISTAN
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Member |
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hi,
I am using oracle 10g with sga_max_size =4GB and db block size 16k. Now i am creating a tablespace with block size 32 kb , kindly tell me that whats value i select for the parameter db_32k_cache_size.
Is there any standard way to calculate the value of this parameter.
Thanks
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| Re: non standard block size [message #519572 is a reply to message #519571] |
Mon, 15 August 2011 00:46  |
John Watson
Messages: 8931
Registered: January 2010
Location: Global Village
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Senior Member |
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I do not believe there is a "standard" way: the optimum value will depend entirely oin your application. So choose a value (500M, perhaps?) and then query the DB cache memory advisor in v$db_cache_advice.
But you must be absolutely clear on why you want to do this. As a rule, you should not use multiple caches for tuning purposes: only for transportable tablespaces.
HTH, John.
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| Re: non standard block size [message #519577 is a reply to message #519575] |
Mon, 15 August 2011 01:06 |
John Watson
Messages: 8931
Registered: January 2010
Location: Global Village
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Senior Member |
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No, it isn't standard.
Oracle has said for many years (I can't quote exactly from memory) that when they run the various TPC bachmarks, they run them against an 8K database, and that using other block sizes does not make any difference.
The problem (undocumented, I'm going by discussions with product development some time ago) is that the non-standard buffer size pools do not have a buffer replacement algorithm that is as well optimized as that for the default pool. So don't use them unless you have too.
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