On Sun, 23 Mar 2025, Laurenz Albe wrote:
On Thu, 2025-03-20 at 23:48 +0100, Dimitrios Apostolou wrote:
Performance issues: (important as my db size is >5TB)
* WAL writes: I didn't manage to avoid writing to the WAL, despite having
setting wal_level=minimal. I even wrote my own function to ALTER all
tables to UNLOGGED, but failed with "could not change table T to
unlogged because it references logged table". I'm out of ideas on this
one.
You'd have to create an load the table in the same transaction, that is,
you'd have to run pg_restore with --single-transaction.
That would restore the schema from the dump, while I want to create the
schema from the SQL code in version control.
Something that might work, would be for pg_restore to issue a TRUNCATE
before the COPY. I believe this would require superuser privelege though,
that I would prefer to avoid. Currently I issue TRUNCATE for all tables
manually before running pg_restore, but of course this is in a different
transaction so it doesn't help.
By the way do you see potential problems with using --single-transaction
to restore billion-rows tables?
Thank you,
Dimitris
