>note postgres' WAL archive is by block, not by transaction.
My understanding is that only the first time a block is updated after a checkpoint, is the entire block is written to the WAL logs. And for that full_page_writes has to be set to ON. The only other time PG writes entire block to the WAL is during the time of backup regardless of full_page_writes setting. AFAIK rest of the time, WAL takes only row changes. Otherwise PG will be generating large number of WAL logs. I hope I am right :-) > also note that postgres effectively does copy-on-write, since update's are > treated >as insert+delete, so the same blocks aren't written over and over nearly >as much as they might be in the oracle storage model. Good point. -- View this message in context: http://www.postgresql-archive.org/Incremental-Level-1-backup-in-PG-tp5951072p5951343.html Sent from the PostgreSQL - general mailing list archive at Nabble.com. -- Sent via pgsql-general mailing list (pgsql-general@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
