maria-discuss team mailing list archive

[Justin Swanhart <greenlion@xxxxxxxxx>]

Workbench uses EXPLAIN FORMAT=JSON which is different from optimizer trace.
 Optimizer trace allows us to very accurately determine what indexes were
used, why ICP was picked, etc.  It allows us to see when things like the
exists strategy is used for a subquery instead of materializing it.  Lots
of very great stuff from it that is not available from EXPLAIN FORMAT=JSON.

The optimizer trace information is available in a special information
schema table.


On Fri, Feb 14, 2014 at 8:23 PM, Colin Charles <colin@xxxxxxxxxxx> wrote:

>
> On 15 Feb 2014, at 11:35, Roberto Spadim <roberto@xxxxxxxxxxxxx> wrote:
>
> > here:
> > https://lists.launchpad.net/maria-developers/msg05719.html
> >
>
> isn't this just the standard DBUG_ENTER(), DBUG_PRINT() of the SE API?
>
> extracts from https://mariadb.com/kb/en/plans-for-10x/ :
>         * QA request: better EXPLAIN (HIGH priority; MP; Spetrunia)
>                 * required in order to debug performance issues in queries
> without knowing the query or the data;
>                 * the customer will only provide EXPLAIN and SHOW output,
> we need to debug based on that; (need examples)
>                 * Perhaps optimizer trace is what we need
>
>         * U/C at Oracle: OPTIMIZER tracing spetrunia: report actual
> estimates, and all decisions of the optimizer, including why an index was
> *not* picked, etc.
>                 * want to change for 5.7
>
>
> > 2014-02-15 1:21 GMT-02:00 Justin Swanhart <greenlion@xxxxxxxxx>:
> > Can you point to the docs on the mariadb implementation?  Writing tools
> to support competing implementations of the same feature is not fun.
> >
>
> i don't think they are the same feature. optimizer tracing, and its
> accompanying json output is something that mariadb 10.0 will not have, but
> something we probably need in future versions (10.1) to remain "backwards
> compatible".
>
> i see mysql workbench as a front-end tool supporting optimizer trace -- do
> you know of more justin?
>
> cheers,
> -colin
>
>
> >
> >
> > Sent from my iPhone
> >
> > On Feb 14, 2014, at 2:12 PM, Roberto Spadim <roberto@xxxxxxxxxxxxx>
> wrote:
> >
> >> that's the "same" feature of dbug in mariadb
> >>
> >>
> >> 2014-02-14 19:01 GMT-02:00 Tim Callaghan <tmcallaghan@xxxxxxxxx>:
> >> Is this feature or something similar already in MariaDB 10?  If not, is
> it on the roadmap?
> >>
> >> http://dev.mysql.com/doc/internals/en/optimizer-tracing.html
> >>
> >> -Tim Callaghan
> >>
> >> _______________________________________________
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> >>
> >>
> >>
> >>
> >> --
> >> Roberto Spadim
> >> SPAEmpresarial
> >> Eng. Automação e Controle
> >> _______________________________________________
> >> Mailing list: https://launchpad.net/~maria-discuss
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> >> Unsubscribe : https://launchpad.net/~maria-discuss
> >> More help   : https://help.launchpad.net/ListHelp
> >
> >
> >
> > --
> > Roberto Spadim
> > SPAEmpresarial
> > Eng. Automação e Controle
> > _______________________________________________
> > Mailing list: https://launchpad.net/~maria-discuss
> > Post to     : maria-discuss@xxxxxxxxxxxxxxxxxxx
> > Unsubscribe : https://launchpad.net/~maria-discuss
> > More help   : https://help.launchpad.net/ListHelp
>
> --
> Colin Charles, Chief Evangelist
> MariaDB | t: +6-012-204-3201 | Skype: colincharles
>
>