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

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.

> +Fast checksums
> +==============
> +
> +Enabling :variable:`innodb_fast_checksum` will use more CPU-efficient
> algorithm, based on 4-byte words which can be beneficial for some
> workloads. Once enabled, turning it off will require table to be
> dump/imported again, since it will fail to start on data files created
> when :variable:`innodb_fast_checksums` was enabled.

s/it/Percona Server/

We should also document behaviour of MySQL (probably a "corrupted
checksum" message).

> +Page sizes other than 16KiB
> +===========================
> +
> +This is controlled by variable :variable:`innodb_page_size`. Changing
> the page size for an existing database is not supported. Table will
> need to be dumped/imported again if compatibility with |MySQL| is
> required.

We should mention that we have not yet tested about compatibility with
the same option in MySQL 5.6

--
Stewart Smith