A quick look through the data for one library which recently had this problem shows that I'm wrong about the frequency of issues/reserves vs deleted biblios actually.
Very low circulation but lots of deleted records. David Cook Systems Librarian Prosentient Systems 72/330 Wattle St Ultimo, NSW 2007 Australia Office: 02 9212 0899 Direct: 02 8005 0595 > -----Original Message----- > From: David Cook [mailto:dc...@prosentient.com.au] > Sent: Tuesday, 6 September 2016 11:57 AM > To: 'Chris Cormack' <chr...@catalyst.net.nz> > Cc: 'Koha-devel' <koha-devel@lists.koha-community.org> > Subject: RE: [Koha-devel] Serious problem > > Mmm, I think that I see what you're saying. In theory, for a library with high > circulation, you would always have a newer checkout in the issues table, > when you're doing a check-in, so it's unlikely that your IDs in the issues table > would be lower than your IDs in your old_issues table. > > When I referred to frequency, I meant that there is probably a higher > frequency of checking in items or fulfilling/cancelling reserves than deleting > biblio records, although I suppose that's a subjective claim. In any case, that's > a good point that the auto_increment is more likely to happen in a library > with low circulation than high circulation. > > I've noticed this problem for years, but previously my communications about > it have been ignored, so we've just mitigated it locally via scripts. Historically, > we thought it only happened after running OPTIMZE TABLE, but thanks to > Mark we see that it's also after MySQL server restarts. > > David Cook > Systems Librarian > Prosentient Systems > 72/330 Wattle St > Ultimo, NSW 2007 > Australia > > Office: 02 9212 0899 > Direct: 02 8005 0595 > > > > -----Original Message----- > > From: Chris Cormack [mailto:chr...@catalyst.net.nz] > > Sent: Tuesday, 6 September 2016 11:40 AM > > To: David Cook <dc...@prosentient.com.au> > > Cc: 'Koha-devel' <koha-devel@lists.koha-community.org> > > Subject: Re: [Koha-devel] Serious problem > > > > * David Cook (dc...@prosentient.com.au) wrote: > > > > > > Chris, what about deletedbiblio and deletedbiblioitem tables? The > > > history there might be more important, as I think we're now > > > including those in the OAI-PMH responses? I reckon those tables > > > would be vulnerable to this as well, although perhaps less likely > > > due to issues and reserves being more high frequency in terms of > inserts/deletions. > > > > > > > As Katrin rightly pointed out to me, frequency is not really the issue. > > This is only a problem when the most recently inserted item is > > deleted/return/issued. > > And then the server is restarted right then. > > > > If you delete from anywhere except the tip of the table, it doesn't matter. > > So if you issue and return something (before anyone else issues > > something) and restart the server then you have the problem with issues. > > So in fact the higher the frequency the way less likely this will be to > happen. > > > > It will most likely only ever happen in a library that does almost no > circulation. > > > > Chris > > > > -- > > Chris Cormack > > Catalyst IT Ltd. > > +64 4 803 2238 > > PO Box 11-053, Manners St, Wellington 6142, New Zealand _______________________________________________ Koha-devel mailing list Koha-devel@lists.koha-community.org http://lists.koha-community.org/cgi-bin/mailman/listinfo/koha-devel website : http://www.koha-community.org/ git : http://git.koha-community.org/ bugs : http://bugs.koha-community.org/
