Hi,

The firebird gurus doesn't seem to thrill to this subject :-(

Anyway, I didn't find any paper / post that could answer my question.

Any hint?

Best regards,
Fabrice Aeschbacher


--- In firebird-support@yahoogroups.com, "Fabrice Aeschbacher"
<fabrice.aeschbacher@s...> wrote:

> Hi,
>
> (LI-V6.3.0.4290 Firebird 1.5 Classic / linux)
>
> I noticed, using gstat -r, that the total versions / max versions
> records for
> one table is allways growing. So I started some tests, to try to
> understand how it works:
>
> CREATE TABLE A (
> ID INTEGER,
> V INTEGER
> );
>
> INSERT INTO A ( ID, V ) VALUES ( 1, 0 );
> COMMIT;
>
> Then I wrote a little C program that does the following:
>
> connect_to_db();
> i = 1;
> while (true) {
> start_transaction();
> sqlexec: UPDATE A SET V = :i WHERE ID = 1;
> i++;
> commit_transaction();
> }
>
> Here is the output of gstat, before the test is started:
>
> A (172)
> Primary pointer page: 548, Index root page: 551
> Average record length: 9.00, total records: 1
> Average version length: 0.00, total versions: 0, max versions: 0
> Data pages: 1, data page slots: 1, average fill: 1%
>
> And during the test:
>
> A (172)
> Primary pointer page: 548, Index root page: 551
> Average record length: 13.00, total records: 1
> Average version length: 9.00, total versions: 47528, max versions:
> 47528
> Data pages: 661, data page slots: 661, average fill: 92%
>
> As we can see, the record versions never stops growing.
> And the UPDATEs are taking more and more time.
>
> When I stop the test program, the number of versions stops growing, but
> is not reset.
>
> When I restart the test program, the number of versions is not

reset, and

> keeps growing.
>
> So the questions:
> - How can I prevent this?
> - What would be the correct way of building an application that has to
> frequently update the same records with different values?
>
>
> One more remark: when I change the test program and make it
> disconnect/reconnect
> every 1000 transactions, then the number of versions grows up to 1000,
> is reset to 0 after the reconnection (in fact, after the first UPDATE
> after the
> reconnection), and restarts growing.
> Does this mean that I must regularly force a reconnection?
>
> Best regards,
> Fabrice Aeschbacher