Hi, On 2023-05-30 21:13:08 -0400, Bruce Momjian wrote: > On Wed, May 31, 2023 at 09:14:20AM +1200, David Rowley wrote: > > On Wed, 31 May 2023 at 08:54, Ron <ronljohnsonjr@xxxxxxxxx> wrote: > > > https://www.postgresql.org/about/news/postgresql-16-beta-1-released-2643/ > > > says "PostgreSQL 16 can also improve the performance of concurrent bulk > > > loading of data using COPY up to 300%." > > > > > > Since pg_dump & pg_restore use COPY (or something very similar), will the > > > speed increase translate to higher speeds for those utilities? > > > > I think the improvements to relation extension only help when multiple > > backends need to extend the relation at the same time. pg_restore can > > have multiple workers, but the tasks that each worker performs are > > only divided as far as an entire table, i.e. 2 workers will never be > > working on the same table at the same time. So there is no concurrency > > in terms of 2 or more workers working on loading data into the same > > table at the same time. > > > > It might be an interesting project now that we have TidRange scans, to > > have pg_dump split larger tables into chunks so that they can be > > restored in parallel. > > Uh, the release notes say: > > <!-- > Author: Andres Freund <andres@xxxxxxxxxxx> > 2023-04-06 [00d1e02be] hio: Use ExtendBufferedRelBy() to extend tables more eff > Author: Andres Freund <andres@xxxxxxxxxxx> > 2023-04-06 [26158b852] Use ExtendBufferedRelTo() in XLogReadBufferExtended() > --> > > <listitem> > <para> > Allow more efficient addition of heap and index pages (Andres Freund) > </para> > </listitem> > > There is no mention of concurrency being a requirement. Is it wrong? I > think there was a question of whether you had to add _multiple_ blocks > ot get a benefit, not if concurrency was needed. This email about the > release notes didn't mention the concurrent requirement: > https://www.postgresql.org/message-id/20230521171341.jjxykfsefsek4kzj%40awork3.anarazel.de There's multiple improvements that work together to get the overall improvement. One part of that is filesystem interactions, another is holding the relation extension lock for a *much* shorter time. The former helps regardless of concurrency, the latter only with concurrency. Regards, Andres
