Thanks for your help Paul, will try gstat und gfix.
Yes, I don't want to shrink the database-file-size, just reuse the
space allocated für version records. but in my case it seems that
sweep does not help because directly after a sweep the next updates
again increase the db-file-size, but these updates should first use
the space freed by the sweep!??

It seems that I have an old open transaction, how can I close/kill
such a transaction?

--- In ib-support@y..., Paul Reeves <paul@f...> wrote:

>
> Unfortunately this is largely how Firebird works. Each update stores
a back
> record version of the data that has changed. These back record
versions are
> saved until a sweep occurs. However, the server does not shrink the
database -
> you have to do that with a backup and restore.
>
> But shrinking the database is not really what you want. What you
want is to
> consistently maintain the database size. This should be possible by
running
> sweep on a regular basis. That should free space used by back
records that are
> no longer needed. Try running gstat -h to get the header page stats,
then
> running gfix -sweep and then running gstat -h again. The transaction
pointers
> should have moved on. From there you should see re-use of the
existing pages.
>
>
> Paul
> --
>
> Paul Reeves
> http://www.ibphoenix.com
> taking InterBase further