maria-developers team mailing list archive

[Igor Babaev <igor@xxxxxxxxxxxx>]

On 06/17/2013 07:51 PM, Zardosht Kasheff wrote:
> +1 on the optimizer tracing. I have found it useful. We've had a
> couple of instances where we looked at where an InnoDB query plan and
> TokuDB query plan diverge for some query, and it showed us bugs in our
> engine.
> 
But as an engine developer you could look into the debug trace as well.
The debug trace contains much more info.
We noticed that with >4-way joins optimizer trace becomes absolutely
useless as one has to look through a huge amount of lines, while with
<4-way joins the optimizer related info can be easily extracted from the
debug trace. The most important: the optimizer trace does not actually
explain WHY the chosen alternative is REALLY better than rejected ones:
the calculation of the costs remains under the cover.

Regards,
Igor.

> Just my $.02.
> 
> -Zardosht
> 
> On Mon, Jun 17, 2013 at 10:37 PM, Igor Babaev <igor@xxxxxxxxxxxx> wrote:
>> On 06/17/2013 04:24 PM, Roberto Spadim wrote:
>>> hi guys, i was reading mysql 5.6 and 5.7 manual
>>> i know that mariadb is very different (a bit) than mysql internally
>>> there's a mysql merge issue or something like that i can see what will
>>> be merged and what not?
>>>
>>> i like the partition lock prune, memcache and optimizer tracer of mysql
>>> 5.6, but today i'm not using it in mariadb (not a problem, but it's nice
>>> features)
>> Roberto,
>>
>> Why do you NEED the optimizer tracer?
>>
>> Regards,
>> Igor.
>>
>>>
>>> --
>>> Roberto Spadim
>>>
>>>
>>>
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