maria-developers team mailing list archive

[Igor Babaev <igor@xxxxxxxxxxxx>]

On 02/12/2013 08:10 AM, Zardosht Kasheff wrote:
> Is there something similar in MariaDB?

I would recommend you to try this feature first and
see how it is helpful for you.
May be that after the first your experience you'll lose any interest in it.

(The direct answer is: No, we don't have optimizer tracing in MariaDB)

Regards.
Igor.

> 
> 
> ---------- Forwarded message ----------
> From: Øystein Grøvlen <oystein.grovlen@xxxxxxxxxx>
> Date: Tue, Feb 12, 2013 at 9:11 AM
> Subject: Re: debugging how query plans are made
> To: Zardosht Kasheff <zardosht@xxxxxxxxx>
> Cc: "internals@xxxxxxxxxxxxxxx" <internals@xxxxxxxxxxxxxxx>
> 
> 
> On 02/12/13 02:54 PM, Zardosht Kasheff wrote:
>>
>> Hello all,
>>
>> In MySQL and/or MariaDB, are there any hooks or methods one can use to
>> learn why a query plan is chosen over alternatives? We sometimes
>> notice that a different query plan is chosen for us than InnoDB (which
>> may be fine, given we are a different storage engine), and we would
>> like to better understand why. Is there any debug parameter that gets
>> MySQL to output decisions made in the optimizer?
> 
> 
> MySQL 5.6 has optimizer tracing which outputs the decisions made by
> the optimizer.  See
> http://dev.mysql.com/doc/internals/en/optimizer-tracing.html
> 
> Hope this helps,
> 
> --
> Øystein
> 
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