--- /dev/null
+# contrib/test_group_deadlocks/Makefile
+
+MODULE_big = test_group_deadlocks
+OBJS = test_group_deadlocks.o $(WIN32RES)
+
+EXTENSION = test_group_deadlocks
+DATA = test_group_deadlocks--1.0.sql
+PGFILEDESC = "test_group_deadlocks - participate in group locking"
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = contrib/test_group_deadlocks
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif
--- /dev/null
+/* contrib/test_group_deadlocks/test_group_deadlocks--1.0.sql */
+
+-- complain if script is sourced in psql, rather than via CREATE EXTENSION
+\echo Use "CREATE EXTENSION test_group_deadlocks" to load this file. \quit
+
+-- Register the function.
+CREATE FUNCTION become_lock_group_leader()
+RETURNS pg_catalog.void
+AS 'MODULE_PATHNAME'
+LANGUAGE C;
+
+CREATE FUNCTION become_lock_group_member(pid pg_catalog.int4)
+RETURNS pg_catalog.bool
+AS 'MODULE_PATHNAME'
+LANGUAGE C;
--- /dev/null
+/*-------------------------------------------------------------------------
+ *
+ * test_group_deadlocks.c
+ * group locking utilities
+ *
+ * Copyright (c) 2010-2014, PostgreSQL Global Development Group
+ *
+ * IDENTIFICATION
+ * contrib/test_group_deadlocks/test_group_deadlocks.c
+ *
+ *-------------------------------------------------------------------------
+ */
+#include "postgres.h"
+
+#include "fmgr.h"
+#include "storage/proc.h"
+#include "storage/procarray.h"
+
+PG_MODULE_MAGIC;
+
+PG_FUNCTION_INFO_V1(become_lock_group_leader);
+PG_FUNCTION_INFO_V1(become_lock_group_member);
+
+
+/*
+ * become_lock_group_leader
+ *
+ * This function makes current backend process as lock group
+ * leader.
+ */
+Datum
+become_lock_group_leader(PG_FUNCTION_ARGS)
+{
+ BecomeLockGroupLeader();
+
+ PG_RETURN_VOID();
+}
+
+/*
+ * become_lock_group_member
+ *
+ * This function makes current backend process as lock group
+ * member of the group owned by the process whose pid is passed
+ * as first argument.
+ */
+Datum
+become_lock_group_member(PG_FUNCTION_ARGS)
+{
+ bool member;
+ PGPROC *procleader;
+ int32 pid = PG_GETARG_INT32(0);
+
+ procleader = BackendPidGetProc(pid);
+ member = BecomeLockGroupMember(procleader, pid);
+
+ PG_RETURN_BOOL(member);
+}