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

At Tue, 19 May 2020 22:56:17 +0900, Atsushi Torikoshi <atorik@gmail.com> wrote in
> On Sat, May 16, 2020 at 6:01 PM legrand legrand <legrand_legrand@hotmail.com>
> wrote:
>
> BTW, I'd also appreciate other opinions about recording the number
> of generic and custom plans on pg_stat_statemtents.

If you/we just want to know how a prepared statement is executed,
couldn't we show that information in pg_prepared_statements view?

=# select * from pg_prepared_statements;
-[ RECORD 1 ]---+----------------------------------------------------
name            | stmt1
statement       | prepare stmt1 as select * from t where b = $1;
prepare_time    | 2020-05-20 12:01:55.733469+09
parameter_types | {text}
from_sql        | t
exec_custom     | 5    <- existing num_custom_plans
exec_total          | 40   <- new member of CachedPlanSource