At Fri, 04 Dec 2020 15:03:25 +0900, torikoshia <torikos...@oss.nttdata.com> wrote in > On 2020-12-04 14:29, Fujii Masao wrote: > > On 2020/11/30 15:24, Tatsuro Yamada wrote: > >> Hi Torikoshi-san, > >> > >>> In this patch, exposing new columns is mandatory, but I think > >>> it's better to make it optional by adding a GUC something > >>> like 'pgss.track_general_custom_plans. > >>> I also feel it makes the number of columns too many. > >>> Just adding the total time may be sufficient. > >> I think this feature is useful for DBA. So I hope that it gets > >> committed to PG14. IMHO, many columns are Okay because DBA can > >> select specific columns by their query. > >> Therefore, it would be better to go with the current design. > > But that design may waste lots of memory. No? For example, when > > plan_cache_mode=force_custom_plan, the memory used for the columns > > for generic plans is not used. > > > > Yeah. > > ISTM now that creating pg_stat_statements_xxx views > both for generic andcustom plans is better than my PoC patch. > > And I'm also struggling with the following. > > | However, I also began to wonder how effective it would be to just > | distinguish between generic and custom plans. Custom plans can > | include all sorts of plans. and thinking cache validation, generic > | plans can also include various plans. > > | Considering this, I'm starting to feel that it would be better to > | not just keeping whether generic or cutom but the plan itself as > | discussed in the below thread.
FWIW, that seems to me to be like some existing extension modules, pg_stat_plans or pg_store_plans.. The former is faster but may lose plans, the latter doesn't lose plans but slower. I feel that we'd beter consider simpler feature if we are intendeng it to be a part of a contrib module, > Yamada-san, > > Do you think it's effective just distinguish between generic > and custom plans? > > Regards, regards. -- Kyotaro Horiguchi NTT Open Source Software Center
