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Treat a WAL sender process that hasn't started streaming yet as a regular

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backend, as far as the postmaster shutdown logic is concerned. That means,
fast shutdown will wait for WAL sender processes to exit before signaling
bgwriter to finish. This avoids race conditions between a base backup stopping
or starting, and bgwriter writing the shutdown checkpoint WAL record. We don't
want e.g the end-of-backup WAL record to be written after the shutdown
checkpoint.
This commit is contained in:
Heikki Linnakangas
2011-01-15 16:27:40 +02:00
parent fcd810c69a
commit 8f5d65e916
3 changed files with 32 additions and 2 deletions
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23
src/backend/storage/ipc/pmsignal.c
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@@ -49,6 +49,8 @@
*
* Actually there is a fourth state, WALSENDER. This is just like ACTIVE,
* but carries the extra information that the child is a WAL sender.
* WAL senders too start in ACTIVE state, but switch to WALSENDER once they
* start streaming the WAL (and they never go back to ACTIVE after that).
*/
#define PM_CHILD_UNUSED 0 /* these values must fit in sig_atomic_t */
@@ -225,8 +227,25 @@ MarkPostmasterChildActive(void)
Assert(slot > 0 && slot <= PMSignalState->num_child_flags);
slot--;
Assert(PMSignalState->PMChildFlags[slot] == PM_CHILD_ASSIGNED);
PMSignalState->PMChildFlags[slot] =
(am_walsender ? PM_CHILD_WALSENDER : PM_CHILD_ACTIVE);
PMSignalState->PMChildFlags[slot] = PM_CHILD_ACTIVE;
}
/*
* MarkPostmasterChildWalSender - mark a postmaster child as a WAL sender
* process. This is called in the child process, sometime after marking the
* child as active.
*/
void
MarkPostmasterChildWalSender(void)
{
int slot = MyPMChildSlot;
Assert(am_walsender);
Assert(slot > 0 && slot <= PMSignalState->num_child_flags);
slot--;
Assert(PMSignalState->PMChildFlags[slot] == PM_CHILD_ACTIVE);
PMSignalState->PMChildFlags[slot] = PM_CHILD_WALSENDER;
}
/*