On Wed, 2 Apr 2025, Adrian Klaver wrote:
On 4/2/25 10:39 AM, Adrian Klaver wrote:
--clean will drop the object entirely not TRUNCATE.
I'm guessing that this is being done by you per:
https://www.postgresql.org/message-id/53760c70-4a87-a453-9e02-57abc9cb2e54%40gmx.net
"After each failed attempt, I need to issue a TRUNCATE table1,table2,...
before I try again. "
Oops, forgot to engage brain.
From pg_backup_archiver.c:
* In parallel restore, if we created the table earlier in
* this run (so that we know it is empty) and we are not
* restoring a load-via-partition-root data item then we
* wrap the COPY in a transaction and precede it with a
* TRUNCATE. If wal_level is set to minimal this prevents
* WAL-logging the COPY. This obtains a speedup similar
* to that from using single_txn mode in non-parallel
* restores.
This makes sense. It creates the table earlier, and then truncates it just
before copying data into it. I wonder if this really circumvents the WAL
since I don't have --single-transaction (incompatible to -j).
Dimitris
