On Wed, 16 Jan 2019 at 01:02, Tatsuo Ishii <is...@sraoss.co.jp> wrote:
> > From: Tatsuo Ishii [mailto:is...@sraoss.co.jp] > >> But pg_is_in_recovery() returns true even for a promoting standby. So > >> you have to wait and retry to send pg_is_in_recovery() until it > >> finishes the promotion to find out it is now a primary. I am not sure > >> if backend out to be responsible for this process. If not, libpq would > >> need to handle it but I doubt it would be possible. > > > > Yes, the application needs to retry connection attempts until success. > That's not different from PgJDBC and other DBMSs. > > I don't know what PgJDBC is doing, however I think libpq needs to do > more than just retrying. > > 1) Try to find a node on which pg_is_in_recovery() returns false. If > found, then we assume that is the primary. We also assume that > other nodes are standbys. done. > > 2) If there's no node on which pg_is_in_recovery() returns false, then > we need to retry until we find it. To not retry forever, there > should be a timeout counter parameter. > > IIRC this is essentially what pgJDBC does. Dave Cramer da...@postgresintl.com www.postgresintl.com > >
