Thanks for the explanation. On Thu, Nov 23, 2023 at 10:55 AM Tom Lane <t...@sss.pgh.pa.us> wrote:
> Ron Johnson <ronljohnso...@gmail.com> writes: > > On Thu, Nov 23, 2023 at 3:37 AM Laurenz Albe <laurenz.a...@cybertec.at> > > wrote: > >> You can avoidwriting WAL if you set "wal_level = minimal", restart > >> PostgreSQL > >> and restore the dump with the --single-transaction option. > > > Why does "--single-transaction" prevent WAL writes? I'd expect _more_ > > pg_wal growth from One Ginormous Transaction. > > I don't recall all the details offhand, but there's some optimization > concerned with not writing WAL if COPY's target table was created in > the current transaction. WAL will still be made for the catalog > changes, but usually the bulk of the WAL for a pg_restore run comes > from loading data, and this recipe eliminates that. (Of course, > you cannot use it on a replication primary.) > > regards, tom lane >
