> 2. > I think users can set ' wal_receiver_status_interval ' to 0 or more > than 'wal_sender_timeout'. But is this a frequent use-case scenario or > do we see DBAs setting these in such a way by mistake? If so, then I > think, it is better to give Warning message in such a case when a user > tries to create or alter a subscription with a large 'min_apply_delay' > (>= 'wal_sender_timeout') , rather than leaving it to the user's > understanding that WalSender may repeatedly timeout in such a case. > Parse_subscription_options and AlterSubscription can be modified to > log a warning. Any thoughts?
Yes, DBAs may set wal_receiver_status_interval to more than wal_sender_timeout by mistake. But to handle the scenario we must compare between min_apply_delay *on subscriber* and wal_sender_timeout *on publisher*. Both values are not transferred to opposite sides, so the WARNING cannot be raised. I considered that such a mechanism seemed to be complex. The discussion around [1] may be useful. [1]: https://www.postgresql.org/message-id/CAA4eK1Lq%2Bh8qo%2BrqGU-E%2BhwJKAHYocV54y4pvou4rLysCgYD-g%40mail.gmail.com Best Regards, Hayato Kuroda FUJITSU LIMITED
