--- In IBObjects@y..., "Arno Garrels" <arno.garrels@g...> wrote:

> Sven, Lester,
>
> Sounds logical, but I'm rather sure, there are no open transactions

when I

> start a loop.
>
> All datasets are set to AutoCommit.

Autocommint performs a CommitRetaining, that is not a true commit.
I've the feeling that you have transaction not "hard committed" during
operation, that prevents the use of free space. Then you terminate the
work, so you have unused free space + new allocated one, and this
every day.
I'm not a guru on this, so I could tell you lies, but as far as I
remember reading posts in this newsgroup, I'm sure that a
"myTransaction.Commit" will help a lot.
Maybe some more clever IBO user here will tell you where/how do it at
the best for your problem.
In the meanwhile, read some tech sheets about transactions on the
Ibobjects site, I'm sure you will fined them very interesting.
regards
Marco Menardi