On Wed, Apr 12, 2017 at 11:46 PM, Peter Eisentraut <peter.eisentr...@2ndquadrant.com> wrote: > On 4/12/17 00:48, Masahiko Sawada wrote: >> On Wed, Apr 12, 2017 at 1:28 PM, Peter Eisentraut >>> Perhaps instead of a global last_start_time, we store a per relation >>> last_start_time in SubscriptionRelState? >> >> I was thinking the same. But a problem is that the list of >> SubscriptionRelState is refreshed whenever the syncing table state >> becomes invalid (table_state_valid = false). I guess we need to >> improve these logic including GetSubscriptionNotReadyRelations(). > > The table states are invalidated on a syscache callback from > pg_subscription_rel, which happens roughly speaking when a table > finishes the initial sync. So if we're worried about failing tablesync > workers relaunching to quickly, this would only be a problem if a > tablesync of another table finishes right in that restart window. That > doesn't seem a terrible issue to me. >
I think the table states are invalidated whenever the table sync worker starts, because the table sync worker updates its status of pg_subscription_rel and commits it before starting actual copy. So we cannot rely on that. I thought we can store last_start_time into pg_subscription_rel but it might be overkill. I'm now thinking to change GetSubscriptionNotReadyRealtions so that last_start_time in SubscriptionRelState is taken over to new list. Regards, -- Masahiko Sawada 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
