On Sun, Mar 6, 2011 at 5:26 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On Sun, 2011-03-06 at 16:58 +0900, Fujii Masao wrote: >> On Sun, Mar 6, 2011 at 4:51 PM, Fujii Masao <masao.fu...@gmail.com> wrote: >> > One comment; what about introducing built-in function to wake up all the >> > waiting backends? When replication connection is closed, if we STONITH >> > the standby, we can safely (for not physical data loss but logical one) >> > switch the primary to standalone mode. But there is no way to wake up >> > the waiting backends for now. Setting synchronous_replication to OFF >> > and reloading the configuration file doesn't affect the existing waiting >> > backends. The attached patch introduces the "pg_wakeup_all_waiters" >> > (better name?) function which wakes up all the backends on the queue. >> >> If unfortunately all connection slots are used by backends waiting for >> replication, we cannot execute such a function. So it makes more sense >> to introduce something like "pg_ctl standalone" command? > > Well, there is one way to end the wait: shutdown, or use > pg_terminate_backend().
Immediate shutdown can release the wait. But smart and fast shutdown cannot. Also pg_terminate_backend() cannot. Since a backend is waiting on the latch and InterruptHoldoffCount is not zero, only SetLatch() or SIGQUIT can cause it to end. > If you simply end the wait you will get COMMIT messages. > > What I would like to do is commit the "safe" patch now. We can then > discuss whether it is safe and desirable to relax some aspects of that > during beta. OK if changing some aspects is acceptable during beta. 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
