Re: Oracle 8.1.7.4 Performance Issues

"Burkhard Kiesel" <burkhard.kiesel_at_siemens.com> wrote in message news:3DFD733A.84080CD3_at_siemens.com...
> Hi,
>
>
> I have a question about Oracle 8.1.7.4 performance, where I need to find
> the answer or solution.
>
> We have a Oracle 8.1.7.4 database installed on a SUN Enterprise 450 with
> 2 processors and 2 GB RAM. The shared_pool is approx. 150 MB in size.
> The db_block_buffer are in total 1,2 GB in size.
>
> When I run the regular queries on the database, the took approx. 0,05 to
> 0,4 seconds for each query. For my tests, I run the query frequently on
> the database and they took between 0,05 and 0,4 sec. That fine for me.
>
> In the next morning, I ran the same queries and the first say 20 queries
> are totally slow, means times from 5 sec up to 20 seconds for each
> query. After the first 20-30 queries, the query time goes down to 0,05
> to 0,4 seconds.
>
> What is the reason for that. There were no queries in the night on the
> database.
> Only a online Backup was running. Is this a normal case, that when
> starting in the morning, the first queries take this long time ?
> Are there any parameters which I can check within Oracle configuration.
>

Hi Burkhard,

As always, the best thing to do is check out any specific waits for the sessions and see what the hold up might be.

I would suspect that cached info is being lost and needs to be reloaded via the first few runs of these queries. This info could be sql areas that need to be reparsed and/or the data blocks that need to re-read from disk.

Once everything is cached again, performance improves.

Then again, it could just be Oracle needing a few fags and cups of coffee to get going in the morning ;)

Cheers

Richard
>
> Regards
>
>
> Burkhard Kiesel
>
Received on Mon Dec 16 2002 - 06:53:49 CST