Don't allow immediate interrupts during authentication anymore.

We used to handle authentication_timeout by setting
ImmediateInterruptOK to true during large parts of the authentication
phase of a new connection.  While that happens to work acceptably in
practice, it's not particularly nice and has ugly corner cases.

Previous commits converted the FE/BE communication to use latches and
implemented support for interrupt handling during both
send/recv. Building on top of that work we can get rid of
ImmediateInterruptOK during authentication, by immediately treating
timeouts during authentication as a reason to die. As die interrupts
are handled immediately during client communication that provides a
sensibly quick reaction time to authentication timeout.

Additionally add a few CHECK_FOR_INTERRUPTS() to some more complex
authentication methods. More could be added, but this already should
provides a reasonable coverage.

While it this overall increases the maximum time till a timeout is
reacted to, it greatly reduces complexity and increases
reliability. That seems like a overall win. If the increase proves to
be noticeable we can deal with those cases by moving to nonblocking
network code and add interrupt checking there.

Reviewed-By: Heikki Linnakangas

1 files changed, 5 insertions, 12 deletions

diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 7e9408e61d9..63573046a9e 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -2880,7 +2880,11 @@ ProcessInterrupts(void)
 		/* As in quickdie, don't risk sending to client during auth */
 		if (ClientAuthInProgress && whereToSendOutput == DestRemote)
 			whereToSendOutput = DestNone;
-		if (IsAutoVacuumWorkerProcess())
+		if (ClientAuthInProgress)
+			ereport(FATAL,
+					(errcode(ERRCODE_QUERY_CANCELED),
+					 errmsg("canceling authentication due to timeout")));
+		else if (IsAutoVacuumWorkerProcess())
 			ereport(FATAL,
 					(errcode(ERRCODE_ADMIN_SHUTDOWN),
 					 errmsg("terminating autovacuum process due to administrator command")));
@@ -2959,17 +2963,6 @@ ProcessInterrupts(void)
 		}
 
 		QueryCancelPending = false;
-		if (ClientAuthInProgress)
-		{
-			ImmediateInterruptOK = false;		/* not idle anymore */
-			LockErrorCleanup();
-			/* As in quickdie, don't risk sending to client during auth */
-			if (whereToSendOutput == DestRemote)
-				whereToSendOutput = DestNone;
-			ereport(ERROR,
-					(errcode(ERRCODE_QUERY_CANCELED),
-					 errmsg("canceling authentication due to timeout")));
-		}
 
 		/*
 		 * If LOCK_TIMEOUT and STATEMENT_TIMEOUT indicators are both set, we