5 files changed, 9 insertions, 8 deletions
diff --git a/mysql-test/r/show_explain.result b/mysql-test/r/show_explain.result
index a4097b9d65e..7c22a2c6435 100644
--- a/mysql-test/r/show_explain.result
+++ b/mysql-test/r/show_explain.result
@@ -735,6 +735,7 @@ grant ALL on test.* to test2@localhost;
 #
 #  First, make sure that user 'test2' cannot do SHOW EXPLAIN on us
 #
+set @show_explain_probe_select_id=1;
 set debug_dbug='d,show_explain_probe_join_exec_start';
 select * from t0 where a < 3;
 show explain for $thr2;
@@ -759,6 +760,7 @@ set debug_dbug='';
 # Now, grant test2 a PROCESSLIST permission, and see that he's able to observe us 
 #
 grant process on *.* to test2@localhost;
+set @show_explain_probe_select_id=1;
 set debug_dbug='d,show_explain_probe_join_exec_start';
 select * from t0 where a < 3;
 show explain for $thr2;
diff --git a/mysql-test/t/show_explain.test b/mysql-test/t/show_explain.test
index 5db6b96d93b..5cfc0a5e202 100644
--- a/mysql-test/t/show_explain.test
+++ b/mysql-test/t/show_explain.test
@@ -739,6 +739,7 @@ connection con1;
 --echo #
 --echo #  First, make sure that user 'test2' cannot do SHOW EXPLAIN on us
 --echo #
+set @show_explain_probe_select_id=1;
 set debug_dbug='d,show_explain_probe_join_exec_start';
 send
 select * from t0 where a < 3;
@@ -772,6 +773,7 @@ grant process on *.* to test2@localhost;
 connect (con2, localhost, test2,,);
 connection con1;
 
+set @show_explain_probe_select_id=1;
 set debug_dbug='d,show_explain_probe_join_exec_start';
 send
 select * from t0 where a < 3;
diff --git a/sql/my_apc.cc b/sql/my_apc.cc
index b5f2300c17f..1cc13f41566 100644
--- a/sql/my_apc.cc
+++ b/sql/my_apc.cc
@@ -22,11 +22,7 @@
 
 #endif
 
-/*
-  Standalone testing:
-    g++ -c -DMY_APC_STANDALONE -g -I.. -I../include -o my_apc.o my_apc.cc
-    g++ -L../mysys -L../dbug -L../strings my_apc.o -lmysys -ldbug -lmystrings -lpthread -lrt
-*/
+/* For standalone testing of APC system, see unittest/sql/my_apc-t.cc */
 
 
 /* 
diff --git a/sql/my_apc.h b/sql/my_apc.h
index 88df8145186..160c19b6353 100644
--- a/sql/my_apc.h
+++ b/sql/my_apc.h
@@ -34,7 +34,9 @@
 */
 
 /*
-  Target for asynchronous procedue calls (APCs).
+  Target for asynchronous procedure calls (APCs). 
+   - A target is running in some particular thread, 
+   - One can make calls to it from other threads.
 */
 class Apc_target
 {
@@ -113,5 +115,3 @@ private:
   }
 };
 
-///////////////////////////////////////////////////////////////////////
-
diff --git a/unittest/sql/my_apc-t.cc b/unittest/sql/my_apc-t.cc
index 741cfbdb124..fccfb6ecd13 100644
--- a/unittest/sql/my_apc-t.cc
+++ b/unittest/sql/my_apc-t.cc
@@ -84,6 +84,7 @@ void *test_apc_service_thread(void *ptr)
   mysql_mutex_destroy(&target_mutex);
   my_thread_end();
   pthread_exit(0);
+  return NULL;
 }