Re: User-facing aspects of serializable transactions

On Mon, Jun 1, 2009 at 6:27 PM, Markus Wanner <markus(at)bluegap(dot)ch> wrote:
> I'm not that eager on the "justifiable by simple inspection" requirement
> above. I don't think a DBA is commonly doing these inspections at all.
>
> I think a tool to measure abort rates per transaction (type) would serve
> the DBA better. Of course there may be false positives, but high abort
> rates should point out the problematic transactions pretty quickly. The
> DBA shouldn't need to care about rare serialization failures or their
> justifiability.

I don't think that's true. It might be true for OLTP transactions
where having to repeat the occasional transaction once or twice for no
reason just means a slower response time. Even there I fear it means
the DBA would never be able to guarantee his response time since there
will always be a chance the transaction will have to be repeated too
many times to fall within the guarantee.

But it's certainly insufficient in an OLAP or DSS environment where
transactions can take hours. If you can never know for sure that
you've written your transaction safely and it might randomly fail and
need to be retried any given day due to internal implementation issues
you can't predict then I would call the system just broken.

--
greg