On Tue, Sep 9, 2008 at 8:38 PM, Heikki Linnakangas <[EMAIL PROTECTED]> wrote: > There's one thing I haven't figured out in this discussion. Does the write > to the disk happen before or after the write to the slave? Can you guarantee > that if a transaction is committed in the master, it's also committed in the > slave, or vice versa?
We can guarantee that a transaction is committed in both the master and the slave if we can wait for that one fsyncs WAL to disk and the other holds it to memory or disk. Even if one fails, the other can continue service. Even if both fail, the node which wrote WAL can continue service. A transaction is lost in neither of the cases. > Agreed. But what happens if you hit that timeout? The stand-alone master continues service when it it that timeout. On the other hand, the slave waits for the order by the sysadmin or the clustering software, then it exits or becomes master. > Should we enforce that > timeout within the server, or should we leave that to the external heartbeat > system? Within the server. All users do not use such an external system. It's not simple for the external system to leave the master stand-alone. 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
