Re: db_block_lru_latches

daud11_at_hotmail.com (Daud) wrote in message news:<f0bf3cc3.0207300540.3e88d45_at_posting.google.com>...
> From oracle documentation, it says that using the default value (1??)
> for db_block_lru_latches may not be good enough especially when # of
> db writers is set to more than 1.

True.

> My question is will it be ok to just
> set it to the maximum which is # of cpu x 2 x 3? Any impact on the
> performance setting it to the max?

I'd say go for it. I've never found any major impact in performance by setting them to the recommended upper limit. It's maybe measurable, but not major by any means. Set them to calculated max according to manual and forget about contention for them in the future. One less problem to worry about. You may incur a slight overhead in searching for a latch, but we're talking the diff between scanning 8 or scanning 24 in a linear list. Hardly the stuff that makes me lose sleep with today's hardware.

>The value of db_block_buffers is
> 100,000.

Yikes! Unless you're running some third party app with a weird behaviour, that's way too high. I've found 20000 seems to be the sweet spot for most apps nowadays. And I find it's more influenced by the nature of the app and the number of concurrent users than by size of db. Of course the "SAPeans" here will disagree with me and allocate at least 8 Gb of buffers. Then again, who cares? Mem is cheap, never mind if you never use it... ;-)

Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam Received on Wed Aug 07 2002 - 18:54:23 CDT