On Sat, Jan 30, 2010 at 12:54 PM, Fujii Masao <masao.fu...@gmail.com> wrote:
>> HOWEVER, I do believe this is an issue we could live with for 9.0 if
>> it's going to lead to a whole lot of additional debugging of SR. But if
>> it's an easy fix, it'll avoid a lot of complaints on pgsql-general.
>
> I think that the latter statement is right.
Though we've not reached consensus on smart shutdown during
recovery yet, I wrote the patch that changes its behavior:
shut down the server (including the startup process and the
walreceiver) as soon as all read-only connections have died.
The code is also available in the 'replication' branch in
my git repository.
And, let's discuss whether something like the attached patch
is required for v9.0 or not.
Regards,
--
Fujii Masao
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center
*** a/src/backend/postmaster/postmaster.c
--- b/src/backend/postmaster/postmaster.c
***************
*** 278,283 **** typedef enum
--- 278,284 ----
PM_RECOVERY_CONSISTENT, /* consistent recovery mode */
PM_RUN, /* normal "database is alive" state */
PM_WAIT_BACKUP, /* waiting for online backup mode to end */
+ PM_WAIT_READONLY, /* waiting for read only backends to exit */
PM_WAIT_BACKENDS, /* waiting for live backends to exit */
PM_SHUTDOWN, /* waiting for bgwriter to do shutdown ckpt */
PM_SHUTDOWN_2, /* waiting for archiver and walsenders to finish */
***************
*** 2165,2171 **** pmdie(SIGNAL_ARGS)
/* and the walwriter too */
if (WalWriterPID != 0)
signal_child(WalWriterPID, SIGTERM);
! pmState = PM_WAIT_BACKUP;
}
/*
--- 2166,2173 ----
/* and the walwriter too */
if (WalWriterPID != 0)
signal_child(WalWriterPID, SIGTERM);
! /* online backup mode is active only when normal processing */
! pmState = (pmState == PM_RUN) ? PM_WAIT_BACKUP : PM_WAIT_READONLY;
}
/*
***************
*** 2840,2845 **** PostmasterStateMachine(void)
--- 2842,2870 ----
}
/*
+ * If we are in a state-machine state that implies waiting for read only
+ * backends to exit, see if they're all gone, and change state if so.
+ */
+ if (pmState == PM_WAIT_READONLY)
+ {
+ /*
+ * PM_WAIT_READONLY state ends when we have no regular backends that
+ * have been started during recovery. Since those backends might be
+ * waiting for the WAL record that conflicts with their queries to be
+ * replayed, recovery and replication need to remain until all read
+ * only backends have been gone away.
+ */
+ if (CountChildren(BACKEND_TYPE_NORMAL) == 0)
+ {
+ if (StartupPID != 0)
+ signal_child(StartupPID, SIGTERM);
+ if (WalReceiverPID != 0)
+ signal_child(WalReceiverPID, SIGTERM);
+ pmState = PM_WAIT_BACKENDS;
+ }
+ }
+
+ /*
* If we are in a state-machine state that implies waiting for backends to
* exit, see if they're all gone, and change state if so.
*/
--
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