If you have done commit's along the way it is pointless to do a rollback
unless there is some recorded significance to where the commits were
performed and things are able to be started where left off.

Jason Wharton
CPS - Mesa AZ
http://www.ibobjects.com

----- Original Message -----
From: "Geoff Worboys" <geoff@...>
To: <IBObjects@yahoogroups.com>
Sent: Tuesday, June 12, 2001 5:53 AM
Subject: Re: [IBO] Volume Data Adding


> Just correcting myself a little bit. I said...
>
> > in most situations I prefer everything to be saved or nothing.
>
> What I have left out is rollback after a problem. So it really should
> be something like...
>
> transaction.BeginBusy(true)
> try
> try
> do everything
> transaction.Commit;
> except
> transaction.Rollback;
> raise;
> end;
> finally
> transaction.EndBusy;
> end;
>
> ensuring that whatever happens the transaction will be closed when the
> process is finished. It does not really matter whether the try/except
> is inside the try/finally or vise versa (I think inside may save one
> cursor flicker ;-)
>
>
> > Thanks Geoff, that's cleared thatup for me. The reason I do the
> > intermediate commits is that it was suggested that with high
> > iteration loops like I'm using that the cache may become
> > overloaded and cause the app to slow down again. I did,
> > originally, only have the one at the end.
> > Do you have any view on that?
>
> What "cache"? Perhaps you have been using cached updates in a prior
> situation?
>
> I guess that Interbase/Firebird probably does have some overhead, and
> there may be "Oldest Active Transaction" issues if the process runs
> for many hours. But I have done large numbers of inserts without
> either the application or the server getting into a bind. The only
> real impact is, if the the application fails and the transaction needs
> to be rolled back. It appears that IB takes an optimistic approach to
> changes, expecting that they will be commited. So a commit is almost
> always quite fast, whereas rollback may take a long time.
>
>
> > In any case, unless the app actually fails there is no way
> > that it can be stopped in the middle of the loop so the
> > entire thing will be saved each time.
>
> I am sure it will stop if I turn the computer off :-)
>
>
> Geoff Worboys
> Telesis Computing
>
>
>
>
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