tmc@... wrote:

> Am running Firebird 1.5.3 Classic on Redhat 8.0 with a Dell 2650 (dual 2.4GHz,
> 4MG RAM). Have about 15 million records in various tables. One in a while
> (like once a week), the database becomes very busy and slows to where MS-Access
> programs can't connect properly (using open source odbc V.2.128). After about
> 20 minutes, the load average (which gets upwards of 28) calms down to around 2
> and the system is not as busy. Requests start to be processed at some point
> during this, so it's not quite an 'outage', but becomes very slow.
>
> What is this doing? We were on Interbase before migrating to FB1.5 with a
> backup and restore. It had the habit of becoming slow over time. Then we
> would do a backup and restore in interbase and it would get faster again.
>
> What are the mechanisms at work here and how can I tune them to not cause an
> interruption of service? Even knowing what parameters to monitor would help
> predict when the interruption would likely occur.
>
> Thanks!
> Tom
>

Tom,

I think it's due to the sweep process that get started because you reach
the sweep interval (defined per database).

How to check it:
Look for your database statistics (use gstat) when the server becomes
slow and watch the gap between your transactions.

How to avoid it:
1.) Keep your transactions as short as possible
2.) Turn off the automatic sweep setting the sweep interval to 0 (use
gfix for this)
3.) Run every day (night) a manual sweep to remove the garbage left on
the database, schedule it to a low usage period.


see you !

--
Alexandre Benson Smith
Development
THOR Software e Comercial Ltda
Santo Andre - Sao Paulo - Brazil
www.thorsoftware.com.br