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db_block_buffer [message #424989] Wed, 07 October 2009 00:29 Go to next message
ranjit@buddhaair.com
Messages: 10
Registered: October 2009
Location: Kathmandu
Junior Member
SQL> SELECT DECODE(state, 0, 'FREE',1,DECODE(lrba_seq,0, 'AVAILABLE', 'BEING USED'),3, 'BEING USED', state) "BLOCK STATUS",
2 COUNT(*) "COUNT"
3 FROM x$bh
4 GROUP BY
5 decode(state,0,'FREE',1,decode(lrba_seq,0,'AVAILABLE',
6 'BEING USED'),3,'BEING USED',state);

BLOCK STATUS COUNT
---------------------------------------- ----------
AVAILABLE 86431
BEING USED 609

This query was issued at pick time, so what does above query mean and can i decrease my db_block_buffer which is currently 76880. Can this lead to performance increase?

Rajin Ranjit
Re: db_block_buffer [message #424991 is a reply to message #424989] Wed, 07 October 2009 00:38 Go to previous messageGo to next message
BlackSwan
Messages: 25046
Registered: January 2009
Location: SoCal
Senior Member
>This query was issued at pick time,
What is "pick time" for us who don't know what this means?

>>so what does above query mean and can i decrease my >db_block_buffer which is currently 76880.
From what does this number appear?

> Can this lead to performance increase?
Yes, no,maybe

What problem are you actually trying to solve?
Re: db_block_buffer [message #424998 is a reply to message #424991] Wed, 07 October 2009 01:39 Go to previous messageGo to next message
ranjit@buddhaair.com
Messages: 10
Registered: October 2009
Location: Kathmandu
Junior Member
Pick time means, sorry i spelt it wrongly it should be peak time, maximum load time. Howerver even if i have spelt it wrongly, you should have understand that.

db_block_buffer=76880 in my parameter file.

I think only few blocks have been used by database, so do i need to make it so large?

Rajin
Re: db_block_buffer [message #425045 is a reply to message #424989] Wed, 07 October 2009 05:12 Go to previous message
JRowbottom
Messages: 5933
Registered: June 2006
Location: Sunny North Yorkshire, ho...
Senior Member
Decreasing your cache size will very rarely lead to performance improvements.

As has already been asked - what problem are you trying to solve?
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