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

On 2020-11-12 14:23, Pavel Stehule wrote:

> yes, the plan self is very interesting information - and information
> if plan was generic or not is interesting too. It is other dimension
> of query - maybe there can be rule - for any query store max 100 most
> slows plans with all attributes. The next issue is fact so first first
> 5 execution of generic plans are not generic in real. This fact should
> be visible too.

Thanks!
However, AFAIU, we can know whether the plan type is generic or custom
from the plan information as described in the manual.

-- https://www.postgresql.org/docs/devel/sql-prepare.html
> If a generic plan is in use, it will contain parameter symbols $n, 
> while a custom plan will have the supplied parameter values substituted 
> into it.

If we can get the plan information, the case like 'first 5 execution
of generic plans are not generic in real' does not happen, doesn't it?


Regards,

--
Atsushi Torikoshi