pg_discon_cancel.v1-heikki.patch

diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index b83a2ef..c36cf31 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -1247,9 +1247,13 @@ internal_flush(void)
 
 			/*
 			 * We drop the buffered data anyway so that processing can
-			 * continue, even though we'll probably quit soon.
+			 * continue, even though we'll probably quit soon. We also
+			 * set a flag that'll cause the next CHECK_FOR_INTERRUPTS
+			 * to terminate the connection.
 			 */
 			PqSendStart = PqSendPointer = 0;
+			ClientConnectionLost = 1;
+			InterruptPending = 1;
 			return EOF;
 		}
 
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 976a832..13ea594 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -2823,6 +2823,19 @@ ProcessInterrupts(void)
 					(errcode(ERRCODE_ADMIN_SHUTDOWN),
 			 errmsg("terminating connection due to administrator command")));
 	}
+	if (ClientConnectionLost)
+	{
+		QueryCancelPending = false;		/* lost connection trumps QueryCancel */
+		ImmediateInterruptOK = false;	/* not idle anymore */
+		DisableNotifyInterrupt();
+		DisableCatchupInterrupt();
+		/* As in quickdie, don't risk sending to client during auth */
+		if (ClientAuthInProgress && whereToSendOutput == DestRemote)
+			whereToSendOutput = DestNone;
+		ereport(FATAL,
+				(errcode(ERRCODE_CONNECTION_FAILURE),
+				 errmsg("connection lost")));
+	}
 	if (QueryCancelPending)
 	{
 		QueryCancelPending = false;
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 9ce64e6..9417c7a 100644
--- a/src/backend/utils/init/globals.c
+++ b/src/backend/utils/init/globals.c
@@ -29,6 +29,7 @@ ProtocolVersion FrontendProtocol;
 volatile bool InterruptPending = false;
 volatile bool QueryCancelPending = false;
 volatile bool ProcDiePending = false;
+volatile bool ClientConnectionLost = false;
 volatile bool ImmediateInterruptOK = false;
 volatile uint32 InterruptHoldoffCount = 0;
 volatile uint32 CritSectionCount = 0;
diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 4ee08fe..8048fc1 100644
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -55,6 +55,12 @@
  * course, only if the interrupt holdoff counter is zero).	See the
  * related code for details.
  *
+ * A lost connection is handled similarly, although the ClientConnectionLost
+ * flag is not set in a signal handler, but whenever we get a nonrecoverable
+ * error writing to the socket. If there was a signal for a broken
+ * connection, we could make use of it by setting ClientConnectionLost in
+ * the signal handler.
+ *
  * A related, but conceptually distinct, mechanism is the "critical section"
  * mechanism.  A critical section not only holds off cancel/die interrupts,
  * but causes any ereport(ERROR) or ereport(FATAL) to become ereport(PANIC)
@@ -70,6 +76,8 @@ extern PGDLLIMPORT volatile bool InterruptPending;
 extern volatile bool QueryCancelPending;
 extern volatile bool ProcDiePending;
 
+extern volatile bool ClientConnectionLost;
+
 /* these are marked volatile because they are examined by signal handlers: */
 extern volatile bool ImmediateInterruptOK;
 extern PGDLLIMPORT volatile uint32 InterruptHoldoffCount;