From c1d589571c497a952d7fbe40d9828655859d746f Mon Sep 17 00:00:00 2001 From: Tom Lane Date: Mon, 11 Jan 2021 14:12:31 -0500 Subject: [PATCH] Try next host after a "cannot connect now" failure. If a server returns ERRCODE_CANNOT_CONNECT_NOW, try the next host, if multiple host names have been provided. This allows dealing gracefully with standby servers that might not be in hot standby mode yet. In the wake of the preceding commit, it might be plausible to retry many more error cases than we do now, but I (tgl) am hesitant to move too aggressively on that --- it's not clear it'd be desirable for cases such as bad-password, for example. But this case seems safe enough. Hubert Zhang, reviewed by Takayuki Tsunakawa Discussion: https://postgr.es/m/BN6PR05MB3492948E4FD76C156E747E8BC9160@BN6PR05MB3492.namprd05.prod.outlook.com --- src/interfaces/libpq/fe-connect.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/src/interfaces/libpq/fe-connect.c b/src/interfaces/libpq/fe-connect.c index a4a8b3ad7a..2b78ed8ec3 100644 --- a/src/interfaces/libpq/fe-connect.c +++ b/src/interfaces/libpq/fe-connect.c @@ -3315,6 +3315,20 @@ keep_going: /* We will come back to here until there is /* OK, we read the message; mark data consumed */ conn->inStart = conn->inCursor; + /* + * If error is "cannot connect now", try the next host if + * any (but we don't want to consider additional addresses + * for this host, nor is there much point in changing SSL + * or GSS mode). This is helpful when dealing with + * standby servers that might not be in hot-standby state. + */ + if (strcmp(conn->last_sqlstate, + ERRCODE_CANNOT_CONNECT_NOW) == 0) + { + conn->try_next_host = true; + goto keep_going; + } + /* Check to see if we should mention pgpassfile */ pgpassfileWarning(conn);