Re: Performance Diagnosis

"Matt" <mccmx_at_hotmail.com> a écrit dans le message de news:cfee5bcf.0406212359.7c0ffe8f_at_posting.google.com...
> > > _db_block_write_batch defaults to the least of:
> > > . db_files * db_file_simultaneous_writes / 2
> > > . db_block_buffers / 4
>
> I think this formula is out of date, quote from Steve Adams' site
> about DBWR changes in 8i:
>
> "The value is now set with _db_writer_chunk_writes
> rather than _db_block_write_batch. The default value appears to be a
> platform
> specific constant - that is, not derived from any other parameters."
>
> So it looks like I have to explicitly set this value with
> "_db_writer_chunk_writes".
>
> "db_file_simultaneous_writes" doesn't exist either...

You're right my post is fully out of date. Only works in v7. As you said, in 8i DBWR write batch size is not dependent on db_files and _db_block_write_batch was changed to _db_writer_chunk_writes and its actual value can be seen with: select kvvival from x$kvii where kviitag='kcbscw';

--
Sorry
Michel Cadot