[thesite] oracle tuning..
Daniel J. Cody
djc at starkmedia.com
Wed Aug 22 12:18:36 CDT 2001
this is mostly for dean or any other oracle heads out there..
i noticed the front page was taking a while to load after I dropped the
new RAM in there, and did some poking around.. it turns out our buffer
cache hit rate was down at like 15% because the db_block_buffers were
set insanely low..
i played with it a bit, and ended up setting db_block_buffers to 3200
and db_files up to 400(from 80)
the buffer cache is hitting about 99.8% right now(after 30 minutes) as a
result.. also the 'getarticles' query on the front page is now just
under 2 seconds to build, down about 3 seconds.
so, everything seems ok, but the only thing i'm concerned about
is oracle's total lack of thirst to use more than 200Mb of memory. now
i don't know if this is just because its been running for a short period
of time or because the buffer recycle is high(which isn't a bad thing)
or what.. linux is also caching about 128Mb of RAM. its still got 450+Mb
of physical *free*, which i think is a bit wacky.
so i guess what i'm getting at is ya, the pages are a ton faster now out
of the DB. but did i set the buffer cache to hit *TOO* often(and is
there such a thing as too many cache hits(cus i wouldnt think so)?)?
anyways, whenever you get a minute, let Jr. DBA here know :)
thanks
.djc.
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