Cancel running query if it is detected that the connection to the client is

lost. The only way we detect that at the moment is when write() fails when
we try to write to the socket.

Florian Pflug with small changes by me, reviewed by Greg Jaskiewicz.

3 files changed, 18 insertions, 1 deletions

diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index b83a2efb698..c36cf318267 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 976a832135e..5bb16e010cc 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -2823,6 +2823,18 @@ 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();
+		/* don't send to client, we already know the connection to be dead. */
+		whereToSendOutput = DestNone;
+		ereport(FATAL,
+				(errcode(ERRCODE_CONNECTION_FAILURE),
+				 errmsg("connection to client lost")));
+	}
 	if (QueryCancelPending)
 	{
 		QueryCancelPending = false;
diff --git a/src/backend/utils/init/globals.c b/src/backend/utils/init/globals.c
index 9ce64e67629..9417c7a3b04 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;