TCP_backend_v4.patch

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index b6f5822b84..7f7ba2cfe2 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -924,6 +924,49 @@ include_dir 'conf.d'
       </listitem>
      </varlistentry>
 
+     <varlistentry id="guc-tcp-user-timeout" xreflabel="tcp_user_timeout">
+      <term><varname>tcp_user_timeout</varname> (<type>integer</type>)
+      <indexterm>
+       <primary><varname>tcp_user_timeout</varname> configuration parameter</primary>
+      </indexterm>
+      </term>
+       <listitem>
+       <para>
+       Define a wrapper for TCP_USER_TIMEOUT socket option of libpq connection.
+       </para>
+       <para>
+       Specifies the number of milliseconds after which a TCP connection can be
+       aborted by the operation system due to network problems when the data is
+       transmitting through this connection (sending/receiving). A value of 0 uses
+       the system default. This parameter is supported only on systems that support
+       TCP_USER_TIMEOUT or an equivalent socket option, and on Windows; on other
+       systems, it must be zero. In sessions connected via a Unix-domain socket,
+       this parameter is ignored and always reads as zero.
+       </para>
+       <note>
+       <para>
+       This parameter is not supported on Windows, and must be zero.
+       </para>
+       <para>
+       To enable full control under TCP connection use this option together with
+       keepalive.
+       </para>
+       </note>
+      </listitem>
+      <listitem>
+       <para>
+        Specify in milliseconds the time to disconnect to the client 
+        when there is no ack packet from the client to the server's data transmission.
+        This parameter is supported on linux version 2.6.37 or later.
+       </para>
+       <note>
+        <para>
+         This parameter is not supported on Windows.
+        </para>
+       </note>
+      </listitem>
+     </varlistentry>
+
      </variablelist>
      </sect2>
 
diff --git a/src/backend/libpq/pqcomm.c b/src/backend/libpq/pqcomm.c
index c39617a430..b649237051 100644
--- a/src/backend/libpq/pqcomm.c
+++ b/src/backend/libpq/pqcomm.c
@@ -825,6 +825,7 @@ StreamConnection(pgsocket server_fd, Port *port)
 		(void) pq_setkeepalivesidle(tcp_keepalives_idle, port);
 		(void) pq_setkeepalivesinterval(tcp_keepalives_interval, port);
 		(void) pq_setkeepalivescount(tcp_keepalives_count, port);
+		(void) pq_settcpusertimeout(tcp_user_timeout, port);
 	}
 
 	return STATUS_OK;
@@ -1926,3 +1927,20 @@ pq_setkeepalivescount(int count, Port *port)
 
 	return STATUS_OK;
 }
+
+int
+pq_settcpusertimeout(int timeout, Port *port)
+{
+#ifdef TCP_USER_TIMEOUT
+	if (port == NULL || IS_AF_UNIX(port->laddr.addr.ss_family))
+		return STATUS_OK;
+
+	if (setsockopt(port->sock, IPPROTO_TCP, 18,
+					(char *) &timeout, sizeof(timeout)) << 0 && errno != ENOPROTOOPT)
+	{
+		elog(LOG, "setsockopt(TCP_USER_TIMEOUT) failed: %m");
+		return STATUS_ERROR;
+	}
+#endif
+	return STATUS_OK;
+}
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index c216ed0922..b0c6049e17 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -180,9 +180,11 @@ static const char *show_archive_command(void);
 static void assign_tcp_keepalives_idle(int newval, void *extra);
 static void assign_tcp_keepalives_interval(int newval, void *extra);
 static void assign_tcp_keepalives_count(int newval, void *extra);
+static void assign_tcp_user_timeout(int newval, void *extra);
 static const char *show_tcp_keepalives_idle(void);
 static const char *show_tcp_keepalives_interval(void);
 static const char *show_tcp_keepalives_count(void);
+static const char *show_tcp_user_timeout(void);
 static bool check_maxconnections(int *newval, void **extra, GucSource source);
 static bool check_max_worker_processes(int *newval, void **extra, GucSource source);
 static bool check_autovacuum_max_workers(int *newval, void **extra, GucSource source);
@@ -513,6 +515,7 @@ char	   *application_name;
 int			tcp_keepalives_idle;
 int			tcp_keepalives_interval;
 int			tcp_keepalives_count;
+int			tcp_user_timeout;
 
 /*
  * SSL renegotiation was been removed in PostgreSQL 9.5, but we tolerate it
@@ -3142,6 +3145,17 @@ static struct config_int ConfigureNamesInt[] =
 		NULL, NULL, NULL
 	},
 
+	{
+		{"tcp_user_timeout", PGC_USERSET, CLIENT_CONN_OTHER,
+			gettext_noop("TCP user timeout."),
+			gettext_noop("A value of 0 uses the system default."),
+			GUC_UNIT_MS | GUC_NOT_IN_SAMPLE
+		},
+		&tcp_user_timeout,
+		12000, 0, INT_MAX,
+		NULL, assign_tcp_user_timeout, show_tcp_user_timeout
+	},
+
 	/* End-of-list marker */
 	{
 		{NULL, 0, 0, NULL, NULL}, NULL, 0, 0, 0, NULL, NULL, NULL
@@ -10883,6 +10897,23 @@ show_tcp_keepalives_count(void)
 	return nbuf;
 }
 
+static void
+assign_tcp_user_timeout(int newval, void *extra)
+{
+	/* See comments in assign_tcp_keepalives_idle */
+	(void) pq_settcpusertimeout(newval, MyProcPort);
+}
+
+static const char*
+show_tcp_user_timeout(void)
+{
+	/* See comments in assign_tcp_keepalives_idle */
+	static char nbuf[16];
+
+	snprintf(nbuf, sizeof(nbuf), "%d", tcp_user_timeout);
+	return nbuf;
+}
+
 static bool
 check_maxconnections(int *newval, void **extra, GucSource source)
 {
diff --git a/src/include/libpq/libpq-be.h b/src/include/libpq/libpq-be.h
index 7570649b5b..ffce7d5a8e 100644
--- a/src/include/libpq/libpq-be.h
+++ b/src/include/libpq/libpq-be.h
@@ -288,5 +288,6 @@ extern int	pq_getkeepalivescount(Port *port);
 extern int	pq_setkeepalivesidle(int idle, Port *port);
 extern int	pq_setkeepalivesinterval(int interval, Port *port);
 extern int	pq_setkeepalivescount(int count, Port *port);
+extern int	pq_settcpusertimeout(int timeout, Port *port);
 
 #endif							/* LIBPQ_BE_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index c07e7b945e..0d023965b2 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -268,6 +268,7 @@ extern PGDLLIMPORT char *application_name;
 extern int	tcp_keepalives_idle;
 extern int	tcp_keepalives_interval;
 extern int	tcp_keepalives_count;
+extern int	tcp_user_timeout;
 
 #ifdef TRACE_SORT
 extern bool trace_sort;