Can't actually increase rollback segments

[Simon Kuhn]

According to the Percona docs, innodb_extra_rsegments can be changed simply by restarting MySQL (with innodb_fast_shutdown disabled). However, I'm not able to get this to actually take effect (as shown by information_schema.innodb_rseg).

With Percona Server 5.1.58-rel12.9 (and also 5.1.62-rel13.2), I've done the following:

- Modify /etc/mysql/my.conf:

   [mysqld]

   innodb_extra_rsegments  = 20

mysql> set global innodb_fast_shutdown=0; \q

/etc/init.d/mysql restart

mysql> show global variables like 'innodb_extra_rsegments';

+------------------------+-------+

| Variable_name          | Value |

+------------------------+-------+

| innodb_extra_rsegments | 20    |

+------------------------+-------+

1 row in set (0.00 sec)

mysql> SELECT COUNT(*) FROM information_schema.innodb_rseg;

+----------+

| COUNT(*) |

+----------+

|        1 |

+----------+

1 row in set (0.00 sec)

Am I missing something?

Simon

[Laurynas Biveinis]

On Thu, May 10, 2012 at 5:44 AM, Simon Kuhn <si...@zombe.es> wrote:
> According to the Percona docs, innodb_extra_rsegments can be changed simply
> by restarting MySQL (with innodb_fast_shutdown disabled). However, I'm not
> able to get this to actually take effect (as shown by
> information_schema.innodb_rseg).

Simon -

Yes, something does not add up here. I have confirmed and put your
report at https://bugs.launchpad.net/percona-server/+bug/997469 , we
will investigate. If you are interested in receiving updates, please
subscribe to that bug report.

Thank you,
--
Laurynas
www.percona.com