On 15 Feb 2014, at 13:01, Justin Swanhart <[email protected]> wrote:
> 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. > i was under the impression that besides just EXPLAIN FORMAT=JSON, workbench could also display the optimizer trace info (from a presentation i saw on this @ mysql connect 2013). that said, i've never tried said feature with workbench (i don't generally use workbench) > The optimizer trace information is available in a special information schema > table. yes, this i know. it is something we clearly are missing (besides, EXPLAIN FORMAT=JSON) do you know any tools that make use of it though? depend on it? i mean usage within mysql 5.6 is something along the lines of: set optimizer_trace="enabled=on"; select * from foo; select * from information_schema.optimizer_trace; i'm just curious if we're accidentally breaking anything/functionality for something else? (you mentioned this too: "Writing tools to support competing implementations of the same feature is not fun.") cheers, -colin > > On Fri, Feb 14, 2014 at 8:23 PM, Colin Charles <[email protected]> wrote: > > On 15 Feb 2014, at 11:35, Roberto Spadim <[email protected]> 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 <[email protected]>: > > 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 <[email protected]> wrote: > > > >> that's the "same" feature of dbug in mariadb > >> > >> > >> 2014-02-14 19:01 GMT-02:00 Tim Callaghan <[email protected]>: > >> 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 > >> > >> _______________________________________________ > >> Mailing list: https://launchpad.net/~maria-discuss > >> Post to : [email protected] > >> 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 : [email protected] > >> 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 : [email protected] > > 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 > > -- Colin Charles, Chief Evangelist MariaDB | t: +6-012-204-3201 | Skype: colincharles _______________________________________________ Mailing list: https://launchpad.net/~maria-discuss Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-discuss More help : https://help.launchpad.net/ListHelp
