Code review comment for lp:~hrvojem/percona-server/bug860922-5.5

On Fri, 24 Feb 2012 07:10:21 -0000, Alexey Kopytov <email address hidden> wrote:
> On 24.02.12 2:22, Stewart Smith wrote:
> > On Thu, 23 Feb 2012 13:00:23 -0000, Hrvoje Matijakovic <email address hidden> wrote:
> >> +Expanded undo slots
> >> +===================
> >> +
> >> +Enabling :variable:`innodb_extra_undoslots` breaks compatibility with
> >> other programs. Specifically, it makes the datafiles unusable for
> >> ibbackup or for a MySQL server that is not run with this option.
> >
> > We should be clear about it being Percona Server, and that MySQL doesn't
> > have this option. They did expand things in 5.6 IIRC (or was it 5.5, I
> > totally forget) - but I think they ended up implementing it in a
> > different way.
> >
>
> It was 5.5 and it was implemented in the absolutely the same way as far
> as on-disk compatibility is concerned.

Ahh excellent. I was trying to recall a conversation from several years
ago regarding it, and I think that was from before there was the InnoDB
fix, so it may have just been them thinking about it.

> In fact, innodb_extra_undoslots doesn't exist in Percona Server 5.5,
> i.e. it just uses the additional segments created by the upstream code.
> All innodb_extra_rseg.patch adds to 5.5 is an I_S status table.

awesome.

(some days I feel I really should have just gone and read the code
rather than attempting to remember a conversation from 4 years ago or
something).
--
Stewart Smith