Re: [Commitfest 2022-07] Patch Triage: Needs Review, Part 1

Hi,

On Thu, Jul 28, 2022 at 02:28:23PM -0700, Jacob Champion wrote:
>
> = Stalled Patches, Need Help =
> [...]
> - Add extra statistics to explain for Nested Loop
>   https://commitfest.postgresql.org/38/2765/
>
> I think the author is hoping for help with testing and performance
> characterization.

As I mentioned in [1], this patch breaks the current assumption that
INSTRUMENT_ALL will lead to statement-level metrics that are generally useful.
According to the benchmark, the proposed patch would add a 1.5% overhead for
pg_stat_statements or any other similar extension that relies on INSTRUMENT_ALL
for no additional information, and I don't think it's acceptable.

I'm still not sure of what is the best way to fix that, but clearly something
has to be done, ideally without requiring every single pg_stat_statements-like
extension to be modified.

> The following are actively being worked and I expect to move them to
> next CF:
>
> - session variables, LET command

Yes please.