Re: DB Block Buffers - Too Much ???

You should also check your buffer cache hit ratio (after the database has been up for some time). If you don't see an improvement, then definately increase it.

>From: Deepak Sharma <sharmakdeep_at_yahoo.com>
>Reply-To: ORACLE-L_at_fatcity.com
>To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>Subject: Re: DB Block Buffers - Too Much ???
>Date: Wed, 21 Jun 2000 12:08:31 -0800
>
>
>Since I don't see a '0', does it mean I need to
>further increase db_block_buffers ?
>
>--- Mike Killough <mwkillough_at_hotmail.com> wrote:
> > No, 0 = free. 1 = read and modified
> >
> >
> > >From: Deepak Sharma <sharmakdeep_at_yahoo.com>
> > >Reply-To: ORACLE-L_at_fatcity.com
> > >To: Multiple recipients of list ORACLE-L
> > <ORACLE-L_at_fatcity.com>
> > >Subject: DB Block Buffers - Too Much ???
> > >Date: Wed, 21 Jun 2000 09:26:00 -0800
> > >
> > >Recently on one of our test systems the Buffer
> > Cache
> > >Hit Ratio was showing 80%. I increased
> > >db_block_buffers from 6000 to 16000, and the after
> > >that the hit ratio has dropped to 55%. It seemed
> > >strange to me that increasing db_block_buffers
> > should
> > >actually decrease performance, until I read Oracle
> > >tuning tips from Richard Niemiec, where he mentions
> > >too much db_block_buffers is not good too, as it
> > may
> > >lead to swapping. My question is how do you
> > determine
> > >whether the buffers are too low or too high ?
> > >
> > >SQL> select state, count(*) from x$bh group by
> > state;
> > >
> > > STATE COUNT(*)
> > >---------- ----------
> > > 1 13047
> > > 3 2953
> > >
> > >Does state = '1' mean this memory is not being used
> > >and if so, should I decrease the buffers ?
> > >
> > >-- Deepak
> > >
> > >=====
> > >Oracle DBA,
> > >Minneapolis, MN
> > >USA
> > >
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> > >Author: Deepak Sharma
> > > INET: sharmakdeep_at_yahoo.com
> > >
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>=====
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>--
>Author: Deepak Sharma
> INET: sharmakdeep_at_yahoo.com
>
>Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
>San Diego, California -- Public Internet access / Mailing Lists
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