There is at least one problem that can appear if you
set db_block_buffers too large - redundant buffers seem
to allow Oracle to breach the _max_cr_dba_block
limit in high-speed OLTP systems. This can result
in very long chains of CR blocks for critical blocks,
which results in the associated CBC latch being
held for a long time and causing silly amounts of
contention.
--
Jonathan Lewis
http://www.jlcomp.demon.co.uk
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Nuno Souto wrote in message ...
>
>>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... ;-)
>
Received on Fri Aug 09 2002 - 02:37:28 CDT
