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

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.
> 
> Regards,


Sorry for the super delayed replay.
I don't think that because I suppose that DBA uses plan_cache_mode if
they faced an inefficient execution plan. And the parameter will be used
as a session-level GUC parameter, not a database-level.


Regards,
Tatsuro Yamada