Re: Buffered log Vs. Unbuffered Log Database

Of even more importance than the buffered logging question is the question "Haven't you got anything better to do on a Saturday night when we've whipped the Jocks?" -----Original Message----- From: Obnoxio The Clown <obnoxio@hotmail.com> To: ntruby@netcomuk.co.uk <ntruby@netcomuk.co.uk>; informix-list@iiug.org <informix-list@iiug.org> Date: 13 November 1999 20:59 Subject: Re: Buffered log Vs. Unbuffered Log Database >From: "Neil Truby" <ntruby@netcomuk.co.uk> >> >>Obnoxio The Clown wrote in message <80gr4d$flt$1@news.xmission.com>... >> >> >May I stick my head out above the parapet on this one: in most cases, if >>you >> >do have some sort of failure that requires some sort of recovery or >> >rollforward, you would probably do some sort of validation exercise to >>see >> >whether any data had been lost. I therefore feel that the extra >>performance >> >you get out of buffered logging justifies its use in most cases >> >>And what if you do have some sort of failure and rely upon automatic "fast" >>recovery? > >My point is just that you're going to possibly lose any COMMIT records in >the log buffer, and how many of those will there be? Most of the sites I've >seen who have a crash have done some kind of audit to see whether they lost >anything. In which case you would find any lost transactions. My perspective >is that the performance benefit outweighs the potential small loss of >resilience. One of the great myths here is that unbuffered logging >guarantees commits aren't lost. But IMHO, there is always a (teensy-weensy >little) chance that you can still lose a commit, even with unbuffered >logging (due to latency), so you might as well get the performance benefits >and keep your eyes open for the risk. > >If you blindly rely on fast recovery without a rollforward audit, you might >as well rely on buffered logging with a rollforward audit. :-) > >If you can't do a rollforward audit, then you should stick to unbuffered >logging, but otherwise I think buffered logging should at least be >considered. I think it suffers from bad press. :-> > >$0.02 > >______________________________________________________ >Get Your Private, Free Email at http://www.hotmail.com >