[Koha-devel] AUTO_INCREMENT fix - prevent data lost

[David Cook]

Hi Katrin,

 

I think there must be some miscommunication here. I’ve experienced the doubled up IDs with reserves, and no data has been lost. It creates a fatal error, since the key already exists in the deleted/old table, and the whole process stops. If a person deleted the data out of the deleted/old table in order to perform the delete, then I could see data being lost, but that’s it. If there is data being lost (perhaps with a different tables than reserves), then something must be horribly wrong with the code to allow it to delete before checking that it can be copied/moved first. That’s all I’m saying.

 

In either case, it’s not good. 

 

David Cook

Systems Librarian

Prosentient Systems

72/330 Wattle St

Ultimo, NSW 2007

Australia

 

Office: 02 9212 0899

Direct: 02 8005 0595

 

From: koha-devel-bounces at lists.koha-community.org [mailto:koha-devel-bounces at lists.koha-community.org] On Behalf Of Katrin
Sent: Friday, 14 July 2017 7:00 PM
To: koha-devel at lists.koha-community.org
Subject: Re: [Koha-devel] AUTO_INCREMENT fix - prevent data lost

 

Hi David,

the problem is not the sequence. The problem is doubled up ids between the tables. If you try to move an entry with an id that already exists in the deleted* or old* table, the data will get lost. But doubled up ids are also likely to cause even more trouble.

Katrin

 

On 13.07.2017 05:07, David Cook wrote:

I’ve looked at the wiki page, but I haven’t looked at Bugzilla or the source code. Why on Earth would we get lost data? Shouldn’t we be copying the code to the “deleted*” tables and THEN deleting it from the main table? 

 

In pre-5.7 versions, you could produce this same behaviour by running OPTIMIZE on a table; it would reset the auto increment counter for the table, and it would cause errors because you couldn’t delete records because there was already a record with that key in the deleted* table. 

 

Anyway, I don’t have time to dwell at the moment, but just adding that to the mix.

 

David Cook

Systems Librarian

Prosentient Systems

72/330 Wattle St

Ultimo, NSW 2007

Australia

 

Office: 02 9212 0899

Direct: 02 8005 0595

 

From: koha-devel-bounces at lists.koha-community.org <mailto:koha-devel-bounces at lists.koha-community.org>  [mailto:koha-devel-bounces at lists.koha-community.org] On Behalf Of Jonathan Druart
Sent: Thursday, 13 July 2017 4:12 AM
To: koha-devel at lists.koha-community.org <mailto:koha-devel at lists.koha-community.org> 
Subject: [Koha-devel] AUTO_INCREMENT fix - prevent data lost

 

Hi devs,

 

Please review and test https://wiki.koha-community.org/wiki/DBMS_auto_increment_fix

I have added a ref from the Koha on Debian wiki page https://wiki.koha-community.org/wiki/Koha_on_Debian#Further_Configuration

It sounds like I should add it somewhere more visible, but do not find where, any ideas?

See also bug 18931 where I would like to add a warning on the about page if data are corrupted.

Please review quickly, that way we can share the tips on the general mailing list.

Cheers,

Jonathan






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