Re: Reconcile stats in find_tabstat_entry() and get rid of PgStat_BackendFunctionEntry

Hi,

On 2023-02-15 09:21:48 +0100, Drouvot, Bertrand wrote:
> diff --git a/src/backend/utils/activity/pgstat_relation.c b/src/backend/utils/activity/pgstat_relation.c
> index f793ac1516..b26e2a5a7a 100644
> --- a/src/backend/utils/activity/pgstat_relation.c
> +++ b/src/backend/utils/activity/pgstat_relation.c
> @@ -471,20 +471,46 @@ pgstat_fetch_stat_tabentry_ext(bool shared, Oid reloid)
>   * Find any existing PgStat_TableStatus entry for rel_id in the current
>   * database. If not found, try finding from shared tables.
>   *
> + * If an entry is found, copy it and increment the copy's counters with their
> + * subtransactions counterparts. Then return the copy. There is no need for the
> + * caller to pfree the copy as the MemoryContext will be reset soon after.
> + *

The "There is no need" bit seems a bit off. Yes, that's true for the current
callers, but who says that it has to stay that way?

Otherwise this looks ready, on a casual scan.

Greetings,

Andres Freund