Re: Performance Diagnosis

From: Matt <mccmx_at_hotmail.com>
Date: 22 Jun 2004 00:40:31 -0700
Message-ID: <cfee5bcf.0406212340.7e6ca423@posting.google.com>

> > _db_block_write_batch defaults to the least of:
> > . db_files * db_file_simultaneous_writes / 2
> > . db_block_buffers / 4
> >
>
> Forgot to mention: don't decrease this parameter to a too low value or you'll get "free buffer wait"
> events.
> I think the best way is to set db_files to a value slighty higher than the number of files and
> adjust db_file_simultaneous_writes to a value that set _db_block_write_batch to a value higher than
> the current DBWR batch size ("physical writes"/"write requests" in v$sysstat).

How do you check the value of "db file simultaneous writes"..? This is not in v$parameter or x$ksppi.

Also there is no entry in v$sysstat for "write requests".

My db_files parameter is set at 1024 but I only have 76 datafiles so I will begin by dropping this value which should decrease my write batch size.

Matt Received on Tue Jun 22 2004 - 02:40:31 CDT