On 24.10.2011 15:29, Fujii Masao wrote:
In your patch, FPW is always WAL-logged at startup even when FPW has not been changed since last shutdown. I don't think that's required. I changed the recovery code so that it keeps track of last FPW indicated by WAL record. Then, at end of startup, if that FPW is equal to FPW specified in postgresql.conf (which means that FPW has not been changed since last shutdown or crash), WAL-logging of FPW is skipped. This change prevents unnecessary WAL-logging. Thought?
One problem with this whole FPW-tracking is that pg_lesslog makes it fail. I'm not sure what we need to do about that - maybe just add a warning to the docs. But it leaves a bit bad feeling in my mouth. Usually we try to make features work orthogonally, without dependencies to other settings. Now this feature requires that full_page_writes is turned on in the master, and also that you don't use pg_lesslog to compress the WAL segments or your base backup might be corrupt. The procedure to take a backup from the standby seems more complicated than taking it on the master - there are more steps to follow.
-- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
