In response to Dan Langille <[EMAIL PROTECTED]>: > Bill Moran wrote: > > > So, my question would be, is dbcheck's performance important enough to > > do that with? As a utility program that doesn't really get run that > > often, it's quite likely a misdirection of resources. Granted, don't > > turn down the patch ... if it helps MySQL without hurting anything else, > > go for it. > > Point: If everything Bacula does is within a transaction, why is dbcheck > required?
Correct me if I'm wrong, but I don't believe that the orphaned filename/ path issue is the result of crashes or other non-transactional issues. I know for a fact that our primary Bacula server has run for many months without failure and it has still accumulated many orphaned paths and filenames. My understanding of what happens is this: 1) Job runs and creates a filename entry for a filename not used before (let's say something really unique, such as would be created by mktemp) 2) Time goes by and that file is deleted, never to be seen again. Eventually, Bacula gets to a point where all the jobs that backed up that filename have been pruned, thus there are no longer any file entries referencing that row. 3) Now we have an orphaned filname row in that table. The same thing can happen with path. The canonical way to solve this would be to keep a reference counter in the filename/path tables that keeps track of how many file entries reference that row. When it's hits 0, it can be deleted. But this creates other issues: 1) What is the overhead of maintaining the reference counter? 2) In the case of a crash, we _must_ fix all reference counters immediately, otherwise records could be deleted that still need to be used. Referential integrity doesn't even gain us much here, as that only guarantees that records can't be created that don't have proper references, it doesn't automatically clean up after deletes. Transactions, if properly implemented, can guarantee that the reference counters will _always_ be correct, even in the event of a crash, but what does that mean for platforms that don't have transaction support or have it turned off? -- Bill Moran Collaborative Fusion Inc. http://people.collaborativefusion.com/~wmoran/ [EMAIL PROTECTED] Phone: 412-422-3463x4023 ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Bacula-devel mailing list Bacula-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bacula-devel
