Subject Re: Very Slow Update Query
Author Jack Mills
--- In firebird-support@yahoogroups.com, "karolbieniaszewski" <liviuslivius@...> wrote:
>
>
> --- In firebird-support@yahoogroups.com, "Jack Mills" <millsjack14@> wrote:
> >
> >
> > --- In firebird-support@yahoogroups.com, "karolbieniaszewski" <liviuslivius@> wrote:
> > >
> > >
> > > --- In firebird-support@yahoogroups.com, "millsjack14" <millsjack14@> wrote:
> > > >
> > > > Hi
> > > >
> > > > I have identical tables in separate databases. when I run an update query on the table in one DB it takes 1 sec, on the other DB it takes 90 sec.
> > > >
> > > > Query
> > > > update disc set area_code = LTrim(area_code)
> > > >
> > > > Table disc has approx 62000 records
> > > > using firebird 1.5.6 on Windows XP
> > > >
> > > > Used IBExpert to check table data are identical & Indices are identical.
> > > >
> > > > Has anyone any idea why there is such a time difference .
> > > >
> > > > Thanks for any help
> > > >
> > > > Jack
> > > >
> > >
> > > 1. record versions - use sweep on both and update index statistics
> > > the best is do backup and restore and then check if time is the same
> > >
> > > 2. fragmentation on hard disk
> > >
> > > Karol Bieniaszewski
> > >
> >
> > Hi Karol
> >
> > Thanks for the response.
> > 1. Did backup & restore, updated index statistics no change still approx 90 sec to update.
> >
> > 2. Defragged the hard drive & update increased to approx 200 sec.
> >
> > seems to be associated with hard disk access?
> >
> > Jack
> >
>
> To test this try create empty partition and there put this restored databases
>
> How long now?
> If long
> Copy once again databases after restore process
> and try deactivate all indexes on this tables
> how long now?
>
> Karol Bieniaszewski
>
Hi Karol

I copied the DB to another drive, update time 98 sec.
I deleted the copy & restored the DB to same second drive, update time 75 sec.
Dropped all indexes, update time 125 sec.
I restored the "Fast" DB to the second drive, update time < 1 sec.

Jack