Hi, On Tue, Sep 22, 2026 at 09:16:30AM +0900, Michael Paquier wrote: > On Mon, Sep 21, 2026 at 05:17:04AM -0400, Andres Freund wrote: > > On 2026-09-21 07:15:44 +0000, Bertrand Drouvot wrote: > >> +/* > >> ------------------------------------------------------------------------- > >> + * > >> + * pgstat_per_backend.c > >> + * Generic infrastructure for per-backend statistics. > >> + * > >> + * This file manages the dedicated per-kind dshashes used for per-backend > >> + * statistics, including entry creation, fetching, snapshots, transfer to > >> + * global statistics, and removal. > > > > It's not entirely obvious to me that a hash table is needed here. If I > > understand correctly, this just going to be used for per-backend versions of > > fixed stats. Which means we could just as well allocate all the memory in > > statically allocated shared memory at server start and have the per-backend > > stats be accessible by nothing more than an array access? > > Yeah. Array access based on an procnum index is still feeling like > the natural thing to do here (I think I've mentioned that upthread?).
Yeah you did mention it. I took your reply in [1] as agreeing with the concern about reserving memory for mostly unused slots, though not necessarily with using a dshash. Is your preference still for the array despite that memory cost? [1]: https://postgr.es/m/anlVx_TD_Q8He5uf%40paquier.xyz Regards, -- Bertrand Drouvot PostgreSQL Contributors Team RDS Open Source Databases Amazon Web Services: https://aws.amazon.com
