Subject Re: Backing up (gbak) slows other operations
Author Adam
The first thing you need to do is work out WHY the other programs are
slowing down. Recognise that Firebird is a database server. At the
end of the day, it has been given the job of storing and retrieving
data on behalf of an application. Of course to achieve this it is
going to request every ounce of CPU and IO it requires to do its job.
Compounding this, there are some issues (particularily with SS) that
mean that if you write a stupid query, other people will be
penalised. I believe some DBMS do some voodoo to decide that those
threads should be of lower priority, (but this is all within the
server process(es), it is not like the DBMS would give up CPU time,
it would just re-allocate it to another one of its tasks).

Alan may have hit the nail on the head. GBak does a sweep (you can
use a switch to disable this). But you need to let us know what is
going on with the server during this slow period. Is the CPU at 99%
on Firebird and the other applications just are not getting enough
CPU time to function effectively, is the hard disk being hit so hard
because you are trying to backup to the same physical disk as the
database resides on (a lot of bouncing will happen) and the other
applications need to wait forever for their IO. Are the other
applications also database applications, which would compete with
Firebird for system resources? Is your GBak transfering to another
machine and effectively filling the network bandwidth, slowing down
other applications?

Or is it simply that you have a .gdb file, and windows is thinking it
is part of the driver rollback stuff. (rename it to .fdb). Or is
there a better time to schedule gbak?

Once you have a better understanding of what is causing the problems,
you should be able to come up with an acceptable solution, or fix
whatever problem the slowness is actually a symptom of.

Adam



--- In firebird-support@yahoogroups.com, Jason Dodson <jasond@b...>
wrote:
> I think you are running into one of my most lamented problems with
firebird... if there is an aggressive connection (IE backup, or a
really CPU/IO
> intensive query), it absolutely refuses to play nice with the other
connections. My guess is there is no (or not very good) scheduler in
Firebird.
>
> Jason
>
> terriertech wrote:
> > Hi all, I have sites that are working with a datafile 24
hours/day.
> > Backups are run using gbak via a windows scheduled task at 4 am.
> >
> > Users are complaining that the backup slows down their work to a
> > crawl. The GDB file is about 1.5 GB, the GBK file is about 1.4
GB,
> > and the backup takes ~10 min. The server has 1 GB of RAM.
> >
> > Any hints for improving the client speed during backup? I am
going to
> > try lowering the priority of the gbak script process, but I
suspect
> > that everything is farmed off to the server process so this won't
make
> > a difference.
> >
> > Thanks!
> > Justin R
> >
> >
> >
> >
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