Re: Is it useful to record whether plans are generic or custom?

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.

Regards,

-- 
Fujii Masao
Advanced Computing Technology Center
Research and Development Headquarters
NTT DATA CORPORATION