Misleading innodb_extra_rsegments documentation

[Laurynas Biveinis]

Original report by Simon Kuhn, verified by me:

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)

[Vadim Tkachenko (vadim-tk)]

That is expected behavior. The documentation is wrong.
For 5.1 you need to create database from zero to have innodb_extra_rsegments working.

[Laurynas Biveinis (laurynas-biveinis)]

In that case we have to fix the docs, assigning to Hrvoje.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-2752