On Wed, Sep 10, 2008 at 12:26 AM, Heikki Linnakangas <[EMAIL PROTECTED]> wrote: > If a slave falls behind, how does it catch up? I guess you're saying that it > can't fall behind, because the master will block before that happens. Also > in asynchronous replication? And what about when the slave is first set up, > and needs to catch up with the master?
The mechanism for the slave to catch up with the master should be provided on the outside of postgres. I think that postgres should provide only WAL streaming, i.e. the master always sends *current* WAL data to the slave. Of course, the master has to send also the current WAL *file* in the initial sending just after the slave starts and connects with it. Because, at the time, current WAL position might be in the middle of WAL file. Even if the master sends only current WAL data, the slave which don't have the corresponding WAL file can not handle it. regards -- Fujii Masao NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers