It's been in mysql for at least 7 years.
http://ebergen.net/wordpress/2009/04/11/longest-beta-ever-myisamchk-parallel-recover/
On Thursday, September 10, 2009, Rob Wultsch <wultsch@stripped> wrote:
> myisam_repair_threads
>
> "If this value is greater than 1, MyISAM table indexes are created in
> parallel (each index in its own thread) during the Repair by sorting
> process. The default value is 1.
> Note :Multi-threaded repair is still beta-quality code."
>
> The note is present is all versions of MySQL manual:
>
>
> http://dev.mysql.com/doc/refman/5.1/en/server-system-variables.html#sysvar_myisam_repair_threads
>
> http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#sysvar_myisam_repair_threads
>
> http://dev.mysql.com/doc/refman/4.1/en/server-system-variables.html#sysvar_myisam_repair_threads
>
>
> Can anyone comment about whether this setting is safe, and if so on
> what major versions?
>
> --
> Rob Wultsch
> wultsch@stripped
>
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>
--
Eric Bergen
eric.bergen@stripped
http://www.ebergen.net
