Re: How to handle deadlocks ?

In <4pi4u1$5i@chleuasme.francenet.fr> cberthet@MicroNet.fr (Christophe Girard-Berthet) writes: > >In article <DsszAL.7MC@world.std.com>, bgw@world.std.com (Bruce G Wilson) says: >> >> >>I've been on a couple of contracting jobs where the client uses >>Sybase (4.9 and System 10). At each place, there were occasions >>where they had problems with deadlock: two processes trying to >>allocate two resources in opposite order. It struck me that part >>of the reason why this is such a problem is that locks are taken >>(and escalated) implicitly in Sybase, so that it's difficult from >>a superficial read of the code to tell when a lock is being taken >>and where the conflict might be occurring. I guess I'm kind of >>surprised to find that locks can't be taken explicitly; with this, >>it would be made clear in the code where the locks are being taken >>and might make it easier to determine where the problem is. >> >>I'm wondering, what kinds of techniques are used in "standard" >>practice with Sybase to detect/prevent deadlocks ? Do IS >>organizations establish rules for accessing the database, like, >>"always do an update to table A before doing an update to table B" ? >>It strikes me that that's really the only way to control this >>sort of problem. >> >>I can't imagine that other databases (Oracle, Informix) don't also >>have this kind of problem. How are deadlocks handled in these ? >> > >Ordering access to the objects in your database is the best way >to REDUCE dealock, keep transactions as short as possible too. Some large sites have thrown hardware at the problem. There was an article in ComputerWorld 'bout 2 years ago on this very subject. It seemed that going to faster I/O ("keeping the transactions as short as possible") made a world of difference. Robert David @ Imperial Technology