Horton

Re: pgsql: Introduce pg_shmem_allocations_numa view

Christoph Berg <myon@debian.org>

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From: Christoph Berg <myon@debian.org>
To: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Cc: Tomas Vondra <tomas@vondra.me>, Andres Freund <andres@anarazel.de>, Tomas Vondra <tomas.vondra@postgresql.org>, pgsql-hackers@lists.postgresql.org
Date: 2025-06-24T18:24:22Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Handle EPERM in pg_numa_init

  2. Add CHECK_FOR_INTERRUPTS into pg_numa_query_pages

  3. Silence valgrind about pg_numa_touch_mem_if_required

  4. Limit the size of numa_move_pages requests

  5. Introduce pg_shmem_allocations_numa view

Attachments

Re: Bertrand Drouvot
> Yes, something like:
> 
> diff --git a/src/backend/storage/ipc/shmem.c b/src/backend/storage/ipc/shmem.c
> index c9ae3b45b76..070ad2f13e7 100644
> --- a/src/backend/storage/ipc/shmem.c
> +++ b/src/backend/storage/ipc/shmem.c
> @@ -689,8 +689,17 @@ pg_get_shmem_allocations_numa(PG_FUNCTION_ARGS)
>                         CHECK_FOR_INTERRUPTS();
>                 }
> 
> -               if (pg_numa_query_pages(0, shm_ent_page_count, page_ptrs, pages_status) == -1)
> -                       elog(ERROR, "failed NUMA pages inquiry status: %m");
> +               #define NUMA_QUERY_CHUNK_SIZE 16  /* has to be <= DO_PAGES_STAT_CHUNK_NR (do_pages_stat())*/
> +
> +               for (uint64 chunk_start = 0; chunk_start < shm_ent_page_count; chunk_start += NUMA_QUERY_CHUNK_SIZE) {
> +                        uint64 chunk_size = Min(NUMA_QUERY_CHUNK_SIZE, shm_ent_page_count - chunk_start);
> +
> +                       if (pg_numa_query_pages(0, chunk_size, &page_ptrs[chunk_start],
> +                                                                       &pages_status[chunk_start]) == -1)
> +                               elog(ERROR, "failed NUMA pages inquiry status: %m");
> +               }
> +
> +               #undef NUMA_QUERY_CHUNK_SIZE

I uploaded a variant of this patch to Debian and it seems to have fixed the issue:

https://buildd.debian.org/status/package.php?p=postgresql-18&suite=experimental

(No reply from linux-mm yet.)

Christoph