Re: Slow inserts

lowjw_at_my-deja.com wrote:
>
> Hi,
>
> We have an application which we bulk inserts
> records into this large table.
>
> It is doing something like 274 records / sec
> (when the table is empty)
> but when it reaches something like 10-12 million
> records, it simply slows down to abt 45 records /
> sec.
>
> We fire 14 streams of this application
> concurrently.
>
> My first thoughts would be the indexes as from
> the session_Waits, it seem to indicate write
> waits completes on index datafiles and the
> figures can be seen to be increasing steadily
> (from utlstat).
>
> We dropped the indexes and re-run and it was
> still the same.
> We start with an empty table and so I believe the
> search for free blocks may not be the cause.
>
> The table is about 25 500Mb extents= 12.5 Gb.
> The index is about 2 500Mb extents=1 Gb.
>
> I would also deduce that the filesystem could be
> the cause but our SA says the load on the machine
> is low and the iostats indicates this too.
>
> So I'm quite puzzled as to why is this happening.
> I have already have 8 dbwr_io_slaves and 4
> lgwr_io_slave up and running.
>
> Joe
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.

Maybe your write batch is too large - often characterised by write complete waits. Ensure that db_files is not set excessively..

HTH

-- 
===========================================
Connor McDonald
http://www.oracledba.co.uk

We are born naked, wet and hungry...then things get worse