5.2.5-99 on CentOS 5.5 x86_64: FederatedX memory leak during SELECTs

[Dave Brady]

We use the FederatedX engine exclusively for SELECTs.

Local (MyISAM) tables are populated with INSERT INTO ... SELECT FROM <Federated table>. Aggregation and other querying is done against the local tables.

Memory is almost always being leaked by the SELECTs. Successive queries usually cause unallocated RAM to be consumed, instead of reusing that which had been already allocated by mysqld. The box eventually starts to page, at which point the instance needs to be restarted.

[Dave Brady (wmf364)]

The FederatedX engine is exactly what we wanted for a system we are running.

This memory leak is really the only issue with it that is hurting us.

Hopefully an easy solution will be found!

[CaptTofu (capttofu)]

I will look into this! I'm glad you find federatedX to be of use!

[CaptTofu (capttofu)]

Hi - btw - how big are the result sets you have using your selects? Just wondering for testing and bug reproduction purposes.

[Dave Brady (wmf364)]

Hi,

The result sets can be fairly large: 10 GB would not be uncommon (or even
the smallest).

On Thu, Sep 8, 2011 at 9:26 AM, CaptTofu <email address hidden> wrote:

> Hi - btw - how big are the result sets you have using your selects? Just
> wondering for testing and bug reproduction purposes.
>
> --
> You received this bug notification because you are subscribed to the bug
> report.
> https://bugs.launchpad.net/bugs/781320
>
> Title:
> 5.2.5-99 on CentOS 5.5 x86_64: FederatedX memory leak during SELECTs
>
> Status in Maria:
> New
>
> Bug description:
> We use the FederatedX engine exclusively for SELECTs.
>
> Local (MyISAM) tables are populated with INSERT INTO ... SELECT FROM
> <Federated table>. Aggregation and other querying is done against the
> local tables.
>
> Memory is almost always being leaked by the SELECTs. Successive
> queries usually cause unallocated RAM to be consumed, instead of
> reusing that which had been already allocated by mysqld. The box
> eventually starts to page, at which point the instance needs to be
> restarted.
>
> To manage notifications about this bug go to:
> https://bugs.launchpad.net/maria/+bug/781320/+subscriptions
>

--
Dave Brady
Senior Database Administrator
Motorola Mobility
Technical Operations