On Thu, Nov 22, 2018 at 1:29 PM Michael Paquier <mich...@paquier.xyz> wrote:
> On Wed, Nov 21, 2018 at 04:09:41PM +0900, Michael Paquier wrote: > > The checkpointer initializes a shutdown checkpoint where it tells to all > > the WAL senders to stop once all the children processes are gone, so it > > seems to me that there is little point in processing > > SyncRepReleaseWaiters() when a WAL sender is in WALSNDSTATE_STOPPING > > state as at this stage syncrep makes little sense. It is still > > necessary to process standby messages at this stage so as the primary > > can shut down when it is sure that all the standbys have flushed the > > shutdown checkpoint record of the primary. > > Just refreshed my memory with c6c33343, which is actually at the origin > of the issue, and my previous argument is flawed. If a WAL sender has > reached WALSNDSTATE_STOPPING no regular backends are around but a WAL > sender could always commit a transaction in parallel which may need to > make sure that its record is flushed and sync'ed, and this needs to make > sure that waiters are correctly released. So it is necessary to patch > up SyncRepGetSyncStandbysPriority and SyncRepGetSyncStandbysQuorum as > mentioned upthread, perhaps adding a comment when looking at > MyWalSnd->state looks adapted. Paul, would you like to write a patch? > -- > Michael > Yes, please see the attached patch.
0001-Allow-stopping-wal-senders-to-be-invovled-in-SyncRep.patch
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