On 2026-Apr-06, Andres Freund wrote:
> I just saw this got committed and wanted to briefly play with it. It works
> nicely!
Yeah, I have to say that Antonin did a great job here.
> Except that at first I tried this in a debugging build, and was briefly rather
> dismayed by the performance. It was really slow. But it's not really related
> to repack / the patches here.
>
> In that config, the assert single-handled increases the time for a repack by
> 35% or so.
Yeah, I saw it was kinda sluggish, but wow, I didn't see *that* much
overhead.
> It's totally valid to not have done so initially, this is a quite complicated
> feature:
>
> I saw this is using individual heap_insert()s during the
> heapam_relation_copy_for_cluster(). Doing individual WAL logged inserts isn't
> exactly cheap or efficient from a WAL volume perspective...
>
> Is there anything other than round tuits preventing us from using
> multi_insert?
>
> That actually would also reduce the cost in the REPACK decoding worker, due to
> having to parse far fewer WAL records.
Nope, not really ... but I don't have any :-(
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
