Re: Performance issue - high Free buff wait

I have never seen the case where more than 3 or 4 DB writer processes were needed. That is usually the case with SGA > 128G and 40 or more cores are available. DBWR is activated at least once per minute, unless there is a segment checkpoint (usually the case with PQ) or log switch. How much data do you write in a minute? What kind of SAN do you have? More DBWR processes means that those processes will each operate on their own buffer chain and each one will fire a few KB in async IO requests. You will gain nothing.

On 1/13/21 11:14 AM, Pap wrote:
> SGA is ~24GB for this database and total host memory is 500gb+ and its
> hosting 5 databases.
> db_writer_processes is set as "8" for this database.

-- 
Mladen Gogala
Database Consultant
http://mgogala.byethost5.com

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