diff --git a/mysql-test/lib/mtr_im.pl b/mysql-test/lib/mtr_im.pl
index ca17516278e..967e92dfcdd 100644
--- a/mysql-test/lib/mtr_im.pl
+++ b/mysql-test/lib/mtr_im.pl
@@ -582,7 +582,7 @@ sub mtr_im_start($$) {
     mtr_add_arg($args, $opt);
   }
 
-  $im->{'pid'} =
+  $im->{'spawner_pid'} =
     mtr_spawn(
       $::exe_im,                        # path to the executable
       $args,                            # cmd-line args
@@ -593,7 +593,7 @@ sub mtr_im_start($$) {
       { append_log_file => 1 }          # append log files
       );
 
-  unless ( $im->{'pid'} )
+  unless ( $im->{'spawner_pid'} )
   {
     mtr_error('Could not start Instance Manager.')
   }
diff --git a/mysql-test/lib/mtr_io.pl b/mysql-test/lib/mtr_io.pl
index 984d834486c..5be1d2ffddb 100644
--- a/mysql-test/lib/mtr_io.pl
+++ b/mysql-test/lib/mtr_io.pl
@@ -39,6 +39,7 @@ sub mtr_get_pid_from_file ($) {
 
     # Read pid number from file
     my $pid= <FILE>;
+    chomp $pid;
     close FILE;
 
     return $pid if $pid=~ /^(\d+)/;
diff --git a/mysql-test/r/im_daemon_life_cycle.result b/mysql-test/r/im_daemon_life_cycle.result
index 4fe15460ae5..a2baeac5f14 100644
--- a/mysql-test/r/im_daemon_life_cycle.result
+++ b/mysql-test/r/im_daemon_life_cycle.result
@@ -6,7 +6,7 @@ instance_name	state
 mysqld1	XXXXX
 mysqld2	offline
 Killing the process...
-Sleeping...
+Waiting...
 Success: the process was restarted.
 Success: server is ready to accept connection on socket.
 
@@ -16,7 +16,7 @@ Success: server is ready to accept connection on socket.
 START INSTANCE mysqld2;
 Success: the process has been started.
 Killing the process...
-Sleeping...
+Waiting...
 Success: the process was restarted.
 Success: server is ready to accept connection on socket.
 SHOW INSTANCE STATUS mysqld1;
diff --git a/mysql-test/r/im_life_cycle.result b/mysql-test/r/im_life_cycle.result
index fb25f4a0768..dcabc8cf4f3 100644
--- a/mysql-test/r/im_life_cycle.result
+++ b/mysql-test/r/im_life_cycle.result
@@ -39,7 +39,7 @@ ERROR HY000: Unknown instance name
 -- 1.1.6.
 --------------------------------------------------------------------
 Killing the process...
-Sleeping...
+Waiting...
 Success: the process was restarted.
 SHOW INSTANCES;
 instance_name	state
@@ -52,7 +52,7 @@ mysqld2	offline
 START INSTANCE mysqld2;
 Success: the process has been started.
 Killing the process...
-Sleeping...
+Waiting...
 Success: the process was killed.
 
 --------------------------------------------------------------------
diff --git a/mysql-test/r/rpl_trigger.result b/mysql-test/r/rpl_trigger.result
index 50bcd071d23..815a87eede5 100644
--- a/mysql-test/r/rpl_trigger.result
+++ b/mysql-test/r/rpl_trigger.result
@@ -944,3 +944,30 @@ c
 ---> Cleaning up...
 DROP TABLE t1;
 DROP TABLE t2;
+drop table if exists t1;
+create table t1(a int, b varchar(50));
+drop trigger not_a_trigger;
+ERROR HY000: Trigger does not exist
+drop trigger if exists not_a_trigger;
+Warnings:
+Note	1360	Trigger does not exist
+create trigger t1_bi before insert on t1
+for each row set NEW.b := "In trigger t1_bi";
+insert into t1 values (1, "a");
+drop trigger if exists t1_bi;
+insert into t1 values (2, "b");
+drop trigger if exists t1_bi;
+Warnings:
+Note	1360	Trigger does not exist
+insert into t1 values (3, "c");
+select * from t1;
+a	b
+1	In trigger t1_bi
+2	b
+3	c
+select * from t1;
+a	b
+1	In trigger t1_bi
+2	b
+3	c
+drop table t1;
diff --git a/mysql-test/r/trigger.result b/mysql-test/r/trigger.result
index 64966b9a3eb..e302f5def1b 100644
--- a/mysql-test/r/trigger.result
+++ b/mysql-test/r/trigger.result
@@ -1256,4 +1256,26 @@ select @a;
 20
 drop table t1;
 drop function f1;
+drop table if exists t1;
+create table t1(a int, b varchar(50));
+drop trigger not_a_trigger;
+ERROR HY000: Trigger does not exist
+drop trigger if exists not_a_trigger;
+Warnings:
+Note	1360	Trigger does not exist
+create trigger t1_bi before insert on t1
+for each row set NEW.b := "In trigger t1_bi";
+insert into t1 values (1, "a");
+drop trigger if exists t1_bi;
+insert into t1 values (2, "b");
+drop trigger if exists t1_bi;
+Warnings:
+Note	1360	Trigger does not exist
+insert into t1 values (3, "c");
+select * from t1;
+a	b
+1	In trigger t1_bi
+2	b
+3	c
+drop table t1;
 End of 5.0 tests
diff --git a/mysql-test/t/func_str.test b/mysql-test/t/func_str.test
index 7ae84ea4767..2ec1afc70ee 100644
--- a/mysql-test/t/func_str.test
+++ b/mysql-test/t/func_str.test
@@ -895,4 +895,208 @@ select benchmark(5+5, pi());
 select benchmark((select 10 from dual), pi());
 select benchmark(@bench_count, pi());
 
+
+#
+# Bug #10963
+# 4294967296 18446744073709551616
+
+select locate('he','hello',-2);
+select locate('lo','hello',-4294967295);
+select locate('lo','hello',4294967295);
+select locate('lo','hello',-4294967296);
+select locate('lo','hello',4294967296);
+select locate('lo','hello',-4294967297);
+select locate('lo','hello',4294967297);
+select locate('lo','hello',-18446744073709551615);
+select locate('lo','hello',18446744073709551615);
+select locate('lo','hello',-18446744073709551616);
+select locate('lo','hello',18446744073709551616);
+select locate('lo','hello',-18446744073709551617);
+select locate('lo','hello',18446744073709551617);
+
+select left('hello', 10);
+select left('hello', 0);
+select left('hello', -1);
+select left('hello', -4294967295);
+select left('hello', 4294967295);
+select left('hello', -4294967296);
+select left('hello', 4294967296);
+select left('hello', -4294967297);
+select left('hello', 4294967297);
+select left('hello', -18446744073709551615);
+select left('hello', 18446744073709551615);
+select left('hello', -18446744073709551616);
+select left('hello', 18446744073709551616);
+select left('hello', -18446744073709551617);
+select left('hello', 18446744073709551617);
+
+select right('hello', 10);
+select right('hello', 0);
+select right('hello', -1);
+select right('hello', -4294967295);
+select right('hello', 4294967295);
+select right('hello', -4294967296);
+select right('hello', 4294967296);
+select right('hello', -4294967297);
+select right('hello', 4294967297);
+select right('hello', -18446744073709551615);
+select right('hello', 18446744073709551615);
+select right('hello', -18446744073709551616);
+select right('hello', 18446744073709551616);
+select right('hello', -18446744073709551617);
+select right('hello', 18446744073709551617);
+
+select substring('hello', 2, -1);
+
+select substring('hello', -1, 1);
+select substring('hello', -2, 1);
+select substring('hello', -4294967295, 1);
+select substring('hello', 4294967295, 1);
+select substring('hello', -4294967296, 1);
+select substring('hello', 4294967296, 1);
+select substring('hello', -4294967297, 1);
+select substring('hello', 4294967297, 1);
+select substring('hello', -18446744073709551615, 1);
+select substring('hello', 18446744073709551615, 1);
+select substring('hello', -18446744073709551616, 1);
+select substring('hello', 18446744073709551616, 1);
+select substring('hello', -18446744073709551617, 1);
+select substring('hello', 18446744073709551617, 1);
+select substring('hello', 1, -1);
+select substring('hello', 1, -4294967295);
+select substring('hello', 1, 4294967295);
+select substring('hello', 1, -4294967296);
+select substring('hello', 1, 4294967296);
+select substring('hello', 1, -4294967297);
+select substring('hello', 1, 4294967297);
+select substring('hello', 1, -18446744073709551615);
+select substring('hello', 1, 18446744073709551615);
+select substring('hello', 1, -18446744073709551616);
+select substring('hello', 1, 18446744073709551616);
+select substring('hello', 1, -18446744073709551617);
+select substring('hello', 1, 18446744073709551617);
+select substring('hello', -1, -1);
+select substring('hello', -4294967295, -4294967295);
+select substring('hello', 4294967295, 4294967295);
+select substring('hello', -4294967296, -4294967296);
+select substring('hello', 4294967296, 4294967296);
+select substring('hello', -4294967297, -4294967297);
+select substring('hello', 4294967297, 4294967297);
+select substring('hello', -18446744073709551615, -18446744073709551615);
+select substring('hello', 18446744073709551615, 18446744073709551615);
+select substring('hello', -18446744073709551616, -18446744073709551616);
+select substring('hello', 18446744073709551616, 18446744073709551616);
+select substring('hello', -18446744073709551617, -18446744073709551617);
+select substring('hello', 18446744073709551617, 18446744073709551617);
+
+select insert('hello', -1, 1, 'hi');
+select insert('hello', -4294967295, 1, 'hi');
+select insert('hello', 4294967295, 1, 'hi');
+select insert('hello', -4294967296, 1, 'hi');
+select insert('hello', 4294967296, 1, 'hi');
+select insert('hello', -4294967297, 1, 'hi');
+select insert('hello', 4294967297, 1, 'hi');
+select insert('hello', -18446744073709551615, 1, 'hi');
+select insert('hello', 18446744073709551615, 1, 'hi');
+select insert('hello', -18446744073709551616, 1, 'hi');
+select insert('hello', 18446744073709551616, 1, 'hi');
+select insert('hello', -18446744073709551617, 1, 'hi');
+select insert('hello', 18446744073709551617, 1, 'hi');
+select insert('hello', 1, -1, 'hi');
+select insert('hello', 1, -4294967295, 'hi');
+select insert('hello', 1, 4294967295, 'hi');
+select insert('hello', 1, -4294967296, 'hi');
+select insert('hello', 1, 4294967296, 'hi');
+select insert('hello', 1, -4294967297, 'hi');
+select insert('hello', 1, 4294967297, 'hi');
+select insert('hello', 1, -18446744073709551615, 'hi');
+select insert('hello', 1, 18446744073709551615, 'hi');
+select insert('hello', 1, -18446744073709551616, 'hi');
+select insert('hello', 1, 18446744073709551616, 'hi');
+select insert('hello', 1, -18446744073709551617, 'hi');
+select insert('hello', 1, 18446744073709551617, 'hi');
+select insert('hello', -1, -1, 'hi');
+select insert('hello', -4294967295, -4294967295, 'hi');
+select insert('hello', 4294967295, 4294967295, 'hi');
+select insert('hello', -4294967296, -4294967296, 'hi');
+select insert('hello', 4294967296, 4294967296, 'hi');
+select insert('hello', -4294967297, -4294967297, 'hi');
+select insert('hello', 4294967297, 4294967297, 'hi');
+select insert('hello', -18446744073709551615, -18446744073709551615, 'hi');
+select insert('hello', 18446744073709551615, 18446744073709551615, 'hi');
+select insert('hello', -18446744073709551616, -18446744073709551616, 'hi');
+select insert('hello', 18446744073709551616, 18446744073709551616, 'hi');
+select insert('hello', -18446744073709551617, -18446744073709551617, 'hi');
+select insert('hello', 18446744073709551617, 18446744073709551617, 'hi');
+
+select repeat('hello', -1);
+select repeat('hello', -4294967295);
+select repeat('hello', 4294967295);
+select repeat('hello', -4294967296);
+select repeat('hello', 4294967296);
+select repeat('hello', -4294967297);
+select repeat('hello', 4294967297);
+select repeat('hello', -18446744073709551615);
+select repeat('hello', 18446744073709551615);
+select repeat('hello', -18446744073709551616);
+select repeat('hello', 18446744073709551616);
+select repeat('hello', -18446744073709551617);
+select repeat('hello', 18446744073709551617);
+
+select space(-1);
+select space(-4294967295);
+select space(4294967295);
+select space(-4294967296);
+select space(4294967296);
+select space(-4294967297);
+select space(4294967297);
+select space(-18446744073709551615);
+select space(18446744073709551615);
+select space(-18446744073709551616);
+select space(18446744073709551616);
+select space(-18446744073709551617);
+select space(18446744073709551617);
+
+select rpad('hello', -1, '1');
+select rpad('hello', -4294967295, '1');
+select rpad('hello', 4294967295, '1');
+select rpad('hello', -4294967296, '1');
+select rpad('hello', 4294967296, '1');
+select rpad('hello', -4294967297, '1');
+select rpad('hello', 4294967297, '1');
+select rpad('hello', -18446744073709551615, '1');
+select rpad('hello', 18446744073709551615, '1');
+select rpad('hello', -18446744073709551616, '1');
+select rpad('hello', 18446744073709551616, '1');
+select rpad('hello', -18446744073709551617, '1');
+select rpad('hello', 18446744073709551617, '1');
+
+select lpad('hello', -1, '1');
+select lpad('hello', -4294967295, '1');
+select lpad('hello', 4294967295, '1');
+select lpad('hello', -4294967296, '1');
+select lpad('hello', 4294967296, '1');
+select lpad('hello', -4294967297, '1');
+select lpad('hello', 4294967297, '1');
+select lpad('hello', -18446744073709551615, '1');
+select lpad('hello', 18446744073709551615, '1');
+select lpad('hello', -18446744073709551616, '1');
+select lpad('hello', 18446744073709551616, '1');
+select lpad('hello', -18446744073709551617, '1');
+select lpad('hello', 18446744073709551617, '1');
+
+
+#
+# BUG#17047: CHAR() and IN() can return NULL without signaling NULL
+# result
+#
+SET @orig_sql_mode = @@SQL_MODE;
+SET SQL_MODE=traditional;
+
+SELECT CHAR(0xff,0x8f USING utf8);
+SELECT CHAR(0xff,0x8f USING utf8) IS NULL;
+
+SET SQL_MODE=@orig_sql_mode;
+
+
 --echo End of 5.0 tests
diff --git a/mysql-test/t/im_daemon_life_cycle.imtest b/mysql-test/t/im_daemon_life_cycle.imtest
index fd19b6f8527..c5b8ee16d9a 100644
--- a/mysql-test/t/im_daemon_life_cycle.imtest
+++ b/mysql-test/t/im_daemon_life_cycle.imtest
@@ -6,59 +6,73 @@
 #
 ###########################################################################
 
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle im_daemon_life_cycle.imtest started.
+
+###########################################################################
+
 --source include/im_check_env.inc
 
-# Turn on reconnect, not on by default anymore
+# Turn on reconnect, not on by default anymore.
 --enable_reconnect
 
 ###########################################################################
-
-# Kill the IM main process and check that the IM Angel will restart the main
-# process.
-
---exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_PATH_PID restarted 30
-
+#
+# The main daemon-life-cycle test case -- check that IM-angel will restart
+# IM-main if it got killed:
+#   - kill IM-main and check that IM-angel will restart it;
+#   - wait for IM-main to start accepting connections before continue test
+#     case;
+#
 ###########################################################################
 
-# Wait for IM to start accepting connections.
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Main-test: starting...
 
---exec $MYSQL_TEST_DIR/t/wait_for_socket.sh $EXE_MYSQL $IM_PATH_SOCK $IM_USERNAME $IM_PASSWORD '' 30
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Killing IM-main...
+--exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_PATH_PID restarted 30 im_daemon_life_cycle
+
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Waiting for IM-main to start accepting connections...
+--exec $MYSQL_TEST_DIR/t/wait_for_socket.sh $EXE_MYSQL $IM_PATH_SOCK $IM_USERNAME $IM_PASSWORD '' 30 im_daemon_life_cycle
+
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Main-test: done.
 
 ###########################################################################
-
 #
 # BUG#12751: Instance Manager: client hangs
+#   - start nonguarded instance (mysqld2);
+#   - kill IM-main and get it restarted by IM-angel;
+#   - check that guarded instance (mysqld1) is accepting connections.
+#   - check that non-guarded instance (mysqld2) were not stopped.
 #
+###########################################################################
 
 --echo
 --echo --------------------------------------------------------------------
 --echo -- Test for BUG#12751
 --echo --------------------------------------------------------------------
 
-# Give some time to begin accepting connections after restart.
-# FIXME: race condition here.
-
---sleep 3
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle BUG12751: starting...
 
 # 1. Start mysqld;
 
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle mysqld2: starting...
 START INSTANCE mysqld2;
-# FIXME: START INSTANCE should be synchronous.
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started
 
-# 2. Restart IM-main: kill it and IM-angel will restart it; wait for IM to
-# start accepting connections again.
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle mysqld2: waiting to start...
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started im_daemon_life_cycle
 
---exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_PATH_PID restarted 30
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle mysqld2: started.
 
---exec $MYSQL_TEST_DIR/t/wait_for_socket.sh $EXE_MYSQL $IM_PATH_SOCK $IM_USERNAME $IM_PASSWORD '' 30
+# 2. Restart IM-main;
+
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Killing IM-main...
+--exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_PATH_PID restarted 30 im_daemon_life_cycle
+
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Waiting for IM-main to start accepting connections...
+--exec $MYSQL_TEST_DIR/t/wait_for_socket.sh $EXE_MYSQL $IM_PATH_SOCK $IM_USERNAME $IM_PASSWORD '' 30 im_daemon_life_cycle
 
 # 3. Issue some statement -- connection should be re-established.
 
-# Give some time to begin accepting connections after restart.
-# FIXME: race condition here.
-
---sleep 3
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle Checking that IM-main processing commands...
 
 --replace_column 3 VERSION_NUMBER 4 VERSION
 SHOW INSTANCE STATUS mysqld1;
@@ -67,6 +81,13 @@ SHOW INSTANCE STATUS mysqld1;
 # So, if it we do not stop it, it will be stopped by mysql-test-run.pl with
 # warning.
 
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle mysqld2: stopping...
 STOP INSTANCE mysqld2;
-# FIXME: STOP INSTANCE should be synchronous.
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 stopped
+
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle mysqld2: waiting to stop...
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 stopped im_daemon_life_cycle
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle mysqld2: stopped.
+
+###########################################################################
+
+--exec $MYSQL_TEST_DIR/t/log.sh im_daemon_life_cycle BUG12751: done.
diff --git a/mysql-test/t/im_life_cycle.imtest b/mysql-test/t/im_life_cycle.imtest
index ddfb62d312e..3721b92e2b7 100644
--- a/mysql-test/t/im_life_cycle.imtest
+++ b/mysql-test/t/im_life_cycle.imtest
@@ -25,7 +25,7 @@
 
 START INSTANCE mysqld2;
 # FIXME: START INSTANCE should be synchronous.
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started im_life_cycle
 
 # FIXME: Result of SHOW INSTANCES here is not deterministic unless START
 # INSTANCE is synchronous. Even waiting for mysqld to start by looking at
@@ -58,7 +58,7 @@ SHOW VARIABLES LIKE 'port';
 
 STOP INSTANCE mysqld2;
 # FIXME: STOP INSTANCE should be synchronous.
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 stopped
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 stopped im_life_cycle
 
 # FIXME: Result of SHOW INSTANCES here is not deterministic unless START
 # INSTANCE is synchronous. Even waiting for mysqld to start by looking at
@@ -121,7 +121,7 @@ STOP INSTANCE mysqld3;
 --echo -- 1.1.6.
 --echo --------------------------------------------------------------------
 
---exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_MYSQLD1_PATH_PID restarted 30
+--exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_MYSQLD1_PATH_PID restarted 30 im_life_cycle
 
 # Give some time to IM to detect that mysqld was restarted. It should be
 # longer than monitoring interval.
@@ -143,7 +143,7 @@ SHOW INSTANCES;
 
 START INSTANCE mysqld2;
 # FIXME: START INSTANCE should be synchronous.
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started im_life_cycle
 
 # FIXME: Result of SHOW INSTANCES here is not deterministic unless START
 # INSTANCE is synchronous. Even waiting for mysqld to start by looking at
@@ -151,7 +151,7 @@ START INSTANCE mysqld2;
 # mysqld has started.
 # SHOW INSTANCES;
 
---exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_MYSQLD2_PATH_PID killed 10
+--exec $MYSQL_TEST_DIR/t/kill_n_check.sh $IM_MYSQLD2_PATH_PID killed 10 im_life_cycle
 
 # FIXME: Result of SHOW INSTANCES here is not deterministic unless START
 # INSTANCE is synchronous. Even waiting for mysqld to start by looking at
diff --git a/mysql-test/t/im_utils.imtest b/mysql-test/t/im_utils.imtest
index 52878f6c2b5..0866b87204a 100644
--- a/mysql-test/t/im_utils.imtest
+++ b/mysql-test/t/im_utils.imtest
@@ -31,10 +31,10 @@ SHOW INSTANCE OPTIONS mysqld2;
 #
 
 START INSTANCE mysqld2;
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 started im_utils
 
 STOP INSTANCE mysqld2;
---exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 stopped
+--exec $MYSQL_TEST_DIR/t/wait_for_process.sh $IM_MYSQLD2_PATH_PID 30 stopped im_utils
 
 #
 # Check 'SHOW LOG FILES' command:
diff --git a/mysql-test/t/kill_n_check.sh b/mysql-test/t/kill_n_check.sh
index a54fb6ef8bb..96c402a638c 100755
--- a/mysql-test/t/kill_n_check.sh
+++ b/mysql-test/t/kill_n_check.sh
@@ -2,74 +2,101 @@
 
 ###########################################################################
 
-# NOTE: this script returns 0 (success) even in case of failure. This is
-# because this script is executed under mysql-test-run[.pl] and it's better to
-# examine particular problem in log file, than just having said that the test
-# case has failed.
+# NOTE: this script returns 0 (success) even in case of failure (except for
+# usage-error). This is because this script is executed under
+# mysql-test-run[.pl] and it's better to examine particular problem in log
+# file, than just having said that the test case has failed.
+
+###########################################################################
+
+basename=`basename "$0"`
+dirname=`dirname "$0"`
+
+###########################################################################
+
+. "$dirname/utils.sh"
 
 ###########################################################################
 
 check_restart()
 {
   if [ ! -r "$pid_path" ]; then
+    log_debug "No '$pid_path' found."
     user_msg='the process was killed'
     return 1
   fi
 
   new_pid=`cat "$pid_path" 2>/dev/null`
+  err_code=$?
 
-  if [ $? -eq 0 -a "$original_pid" = "$new_pid" ]; then
+  log_debug "err_code: $err_code; original_pid: $original_pid; new_pid: $new_pid."
+
+  if [ $err_code -eq 0 -a "$original_pid" = "$new_pid" ]; then
+    log_debug "The process was not restarted."
     user_msg='the process was not restarted'
     return 1
   fi
 
+  log_debug "The process was restarted."
   user_msg='the process was restarted'
   return 0
 }
 
 ###########################################################################
 
-if [ $# -ne 3 ]; then
-  echo "Usage: kill_n_check.sh <pid file path> killed|restarted <timeout>"
-  exit 0
+if [ $# -ne 4 ]; then
+  echo "Usage: $basename <pid file path> killed|restarted <timeout> <test id>"
+  exit 1
 fi
 
 pid_path="$1"
 expected_result="$2"
 total_timeout="$3"
+test_id="$4"
+log_file="$MYSQLTEST_VARDIR/log/$test_id.log"
+
+log_debug "-- $basename: starting --"
+log_debug "pid_path: '$pid_path'"
+log_debug "expected_result: '$expected_result'"
+log_debug "total_timeout: '$total_timeout'"
+log_debug "test_id: '$test_id'"
+log_debug "log_file: '$log_file'"
+
+###########################################################################
 
 if [ "$expected_result" != 'killed' -a \
      "$expected_result" != 'restarted' ]; then
-  echo "Error: invalid second argument ('killed' or 'restarted' expected)."
-  exit 0
+  log_error "Invalid second argument ($expected_result): 'killed' or 'restarted' expected."
+  quit 0
 fi
 
 if [ -z "$pid_path" ]; then
-  echo "Error: invalid PID path ($pid_path)."
-  exit 0
+  log_error "Invalid PID path ($pid_path)."
+  quit 0
 fi
 
 if [ ! -r "$pid_path" ]; then
-  echo "Error: PID file ($pid_path) does not exist."
-  exit 0
+  log_error "PID file ($pid_path) does not exist."
+  quit 0
 fi
 
 if [ -z "$total_timeout" ]; then
-  echo "Error: timeout is not specified."
-  exit 0
+  log_error "Timeout is not specified."
+  quit 0
 fi
 
 ###########################################################################
 
 original_pid=`cat "$pid_path"`
+log_debug "original_pid: $original_pid."
 
-echo "Killing the process..."
+log_info "Killing the process..."
 
 kill -9 $original_pid
 
 ###########################################################################
 
-echo "Sleeping..."
+log_info "Waiting..."
 
 if [ "$expected_result" = "restarted" ]; then
 
@@ -79,37 +106,42 @@ if [ "$expected_result" = "restarted" ]; then
 
   while true; do
 
+    log_debug "cur_attempt: $cur_attempt."
+
     if check_restart; then
-      echo "Success: $user_msg."
-      exit 0
+      log_info "Success: $user_msg."
+      quit 0
     fi
 
     [ $cur_attempt -ge $total_timeout ] && break
 
+    log_debug "Sleeping for 1 second..."
     sleep 1
 
     cur_attempt=`expr $cur_attempt + 1`
 
   done
 
-  echo "Error: $user_msg."
-  exit 0
+  log_error "$user_msg."
+  quit 0
 
 else # $expected_result == killed
 
   # Here we have to sleep for some long time to ensure that the process will
   # not be restarted.
 
+  log_debug "Sleeping for $total_timeout seconds..."
   sleep $total_timeout
 
   new_pid=`cat "$pid_path" 2>/dev/null`
+  log_debug "new_pid: $new_pid."
 
   if [ "$new_pid" -a "$new_pid" -ne "$original_pid" ]; then
-    echo "Error: the process was restarted."
+    log_error "The process was restarted."
   else
-    echo "Success: the process was killed."
+    log_info "Success: the process was killed."
   fi
 
-  exit 0
+  quit 0
 
 fi
diff --git a/mysql-test/t/log.sh b/mysql-test/t/log.sh
new file mode 100755
index 00000000000..20b265087cc
--- /dev/null
+++ b/mysql-test/t/log.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+
+###########################################################################
+
+basename=`basename "$0"`
+dirname=`dirname "$0"`
+
+###########################################################################
+
+. "$dirname/utils.sh"
+
+###########################################################################
+
+if [ $# -lt 2 ]; then
+  echo "Usage: $basename <test id> log message ..."
+  exit 1
+fi
+
+test_id="$1"
+log_file="$MYSQLTEST_VARDIR/log/$test_id.log"
+
+shift
+
+log_debug "$*"
diff --git a/mysql-test/t/rpl_trigger.test b/mysql-test/t/rpl_trigger.test
index 6ec0021635a..9f5f6fc9b4c 100644
--- a/mysql-test/t/rpl_trigger.test
+++ b/mysql-test/t/rpl_trigger.test
@@ -431,6 +431,43 @@ DROP TABLE t2;
 --sync_with_master
 --connection master
 
+#
+# BUG#23703: DROP TRIGGER needs an IF EXISTS
+#
+
+connection master;
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+create table t1(a int, b varchar(50));
+
+-- error ER_TRG_DOES_NOT_EXIST
+drop trigger not_a_trigger;
+
+drop trigger if exists not_a_trigger;
+
+create trigger t1_bi before insert on t1
+for each row set NEW.b := "In trigger t1_bi";
+
+insert into t1 values (1, "a");
+drop trigger if exists t1_bi;
+insert into t1 values (2, "b");
+drop trigger if exists t1_bi;
+insert into t1 values (3, "c");
+
+select * from t1;
+
+save_master_pos;
+connection slave;
+sync_with_master;
+
+select * from t1;
+
+connection master;
+
+drop table t1;
 
 #
 # End of tests
diff --git a/mysql-test/t/trigger.test b/mysql-test/t/trigger.test
index bee2bca47d2..12262894e5b 100644
--- a/mysql-test/t/trigger.test
+++ b/mysql-test/t/trigger.test
@@ -1519,4 +1519,32 @@ connection default;
 drop table t1;
 drop function f1;
 
+#
+# Bug#23703: DROP TRIGGER needs an IF EXISTS
+#
+
+--disable_warnings
+drop table if exists t1;
+--enable_warnings
+
+create table t1(a int, b varchar(50));
+
+-- error ER_TRG_DOES_NOT_EXIST
+drop trigger not_a_trigger;
+
+drop trigger if exists not_a_trigger;
+
+create trigger t1_bi before insert on t1
+for each row set NEW.b := "In trigger t1_bi";
+
+insert into t1 values (1, "a");
+drop trigger if exists t1_bi;
+insert into t1 values (2, "b");
+drop trigger if exists t1_bi;
+insert into t1 values (3, "c");
+
+select * from t1;
+
+drop table t1;
+
 --echo End of 5.0 tests
diff --git a/mysql-test/t/utils.sh b/mysql-test/t/utils.sh
new file mode 100644
index 00000000000..b3f4744947d
--- /dev/null
+++ b/mysql-test/t/utils.sh
@@ -0,0 +1,55 @@
+###########################################################################
+#
+# This file provides utility functions and is included by other scripts.
+#
+# The following global variables must be set before calling functions from this
+# file:
+#   - basename -- base name of the calling script (main application);
+#   - log_file -- where to store log records;
+#
+###########################################################################
+
+log()
+{
+  [ -z "$log_file" ] && return;
+
+  log_level="$1"
+  log_msg="$2"
+  ts=`date`
+
+  echo "[$ts] [$basename] [$log_level] $log_msg" >> "$log_file";
+}
+
+###########################################################################
+
+log_debug()
+{
+  log 'DEBUG' "$1"
+}
+
+###########################################################################
+
+log_info()
+{
+  log 'INFO' "$1"
+  echo "$1"
+}
+
+###########################################################################
+
+log_error()
+{
+  log 'ERROR' "$1"
+  echo "Error: $1"
+}
+
+###########################################################################
+
+quit()
+{
+  exit_status="$1"
+
+  log_debug "-- $basename: finished (exit_status: $exit_status) --"
+
+  exit $exit_status
+}
diff --git a/mysql-test/t/wait_for_process.sh b/mysql-test/t/wait_for_process.sh
index df0f4a17e3a..4c2d89cfea6 100755
--- a/mysql-test/t/wait_for_process.sh
+++ b/mysql-test/t/wait_for_process.sh
@@ -2,11 +2,79 @@
 
 ###########################################################################
 
+# NOTE: this script returns 0 (success) even in case of failure (except for
+# usage-error). This is because this script is executed under
+# mysql-test-run[.pl] and it's better to examine particular problem in log
+# file, than just having said that the test case has failed.
+
+###########################################################################
+
+basename=`basename "$0"`
+dirname=`dirname "$0"`
+
+###########################################################################
+
+. "$dirname/utils.sh"
+
+###########################################################################
+
+check_started()
+{
+  if [ ! -r "$pid_path" ]; then
+    log_debug "No PID-file ($pid_path) found -- not started."
+    return 1
+  fi
+
+  new_pid=`cat "$pid_path" 2>/dev/null`
+  err_code=$?
+
+  log_debug "err_code: $err_code; new_pid: $new_pid."
+
+  if [ $? -ne 0 -o -z "$new_pid" ]; then
+    log_debug "The process was not started."
+    return 1
+  fi
+
+  log_debug "The process was started."
+  return 0
+}
+
+###########################################################################
+
+check_stopped()
+{
+  if [ -r "$pid_path" ]; then
+    log_debug "PID-file '$pid_path' exists -- not stopped."
+    return 1
+  fi
+
+  log_debug "No PID-file ($pid_path) found -- stopped."
+  return 0
+}
+
+###########################################################################
+
+if [ $# -ne 4 ]; then
+  echo "Usage: $basename <pid file path> <total attempts> started|stopped <test id>"
+  exit 1
+fi
+
 pid_path="$1"
 total_attempts="$2"
 event="$3"
+test_id="$4"
+log_file="$MYSQLTEST_VARDIR/log/$test_id.log"
 
-case "$3" in
+log_debug "-- $basename: starting --"
+log_debug "pid_path: '$pid_path'"
+log_debug "total_attempts: '$total_attempts'"
+log_debug "event: '$event'"
+log_debug "test_id: '$test_id'"
+log_debug "log_file: '$log_file'"
+
+###########################################################################
+
+case "$event" in
   started)
     check_fn='check_started';
     ;;
@@ -16,51 +84,31 @@ case "$3" in
     ;;
 
   *)
-    echo "Error: invalid third argument ('started' or 'stopped' expected)."
-    exit 0
+    log_error "Invalid third argument ('started' or 'stopped' expected)."
+    quit 0
 esac
 
 ###########################################################################
 
-check_started()
-{
-  [ ! -r "$pid_path" ] && return 1
-
-  new_pid=`cat "$pid_path" 2>/dev/null`
-
-  [ $? -eq 0 -a "$original_pid" = "$new_pid" ] && return 1
-
-  return 0
-}
-
-###########################################################################
-
-check_stopped()
-{
-  [ -r "$pid_path" ] && return 1
-
-  return 0
-}
-
-###########################################################################
-
 cur_attempt=1
 
 while true; do
 
+  log_debug "cur_attempt: $cur_attempt."
+
   if ( eval $check_fn ); then
-    echo "Success: the process has been $event."
-    exit 0
+    log_info "Success: the process has been $event."
+    quit 0
   fi
 
   [ $cur_attempt -ge $total_attempts ] && break
 
+  log_debug "Sleeping for 1 second..."
   sleep 1
 
   cur_attempt=`expr $cur_attempt + 1`
 
 done
 
-echo "Error: the process has not been $event in $total_attempts secs."
-exit 0
-
+log_error "The process has not been $event in $total_attempts secs."
+quit 0
diff --git a/mysql-test/t/wait_for_socket.sh b/mysql-test/t/wait_for_socket.sh
index b6526b7d19c..1bce74dfd3a 100755
--- a/mysql-test/t/wait_for_socket.sh
+++ b/mysql-test/t/wait_for_socket.sh
@@ -2,9 +2,25 @@
 
 ###########################################################################
 
-if [ $# -ne 6 ]; then
-  echo "Usage: wait_for_socket.sh <executable path> <socket path> <username> <password> <db> <timeout>"
-  exit 0
+# NOTE: this script returns 0 (success) even in case of failure (except for
+# usage-error). This is because this script is executed under
+# mysql-test-run[.pl] and it's better to examine particular problem in log
+# file, than just having said that the test case has failed.
+
+###########################################################################
+
+basename=`basename "$0"`
+dirname=`dirname "$0"`
+
+###########################################################################
+
+. "$dirname/utils.sh"
+
+###########################################################################
+
+if [ $# -ne 7 ]; then
+  echo "Usage: wait_for_socket.sh <executable path> <socket path> <username> <password> <db> <timeout> <test id>"
+  exit 1
 fi
 
 client_exe="$1"
@@ -13,22 +29,34 @@ username="$3"
 password="$4"
 db="$5"
 total_timeout="$6"
+test_id="$7"
+log_file="$MYSQLTEST_VARDIR/log/$test_id.log"
+
+log_debug "-- $basename: starting --"
+log_debug "client_exe: '$client_exe'"
+log_debug "socket_path: '$socket_path'"
+log_debug "username: '$username'"
+log_debug "password: '$password'"
+log_debug "db: '$db'"
+log_debug "total_timeout: '$total_timeout'"
+log_debug "test_id: '$test_id'"
+log_debug "log_file: '$log_file'"
 
 ###########################################################################
 
 if [ -z "$client_exe" ]; then
-  echo "Error: invalid path to client executable ($client_exe)."
-  exit 0;
+  log_error "Invalid path to client executable ($client_exe)."
+  quit 0;
 fi
 
 if [ ! -x "$client_exe" ]; then
-  echo "Error: client by path '$client_exe' is not available."
-  exit 0;
+  log_error "Client by path '$client_exe' is not available."
+  quit 0;
 fi
 
 if [ -z "$socket_path" ]; then
-  echo "Error: invalid socket patch."
-  exit 0
+  log_error "Invalid socket patch ($socket_path)."
+  quit 0
 fi
 
 ###########################################################################
@@ -39,15 +67,19 @@ client_args="--silent --socket=$socket_path --connect_timeout=1 "
 [ -n "$password" ] && client_args="$client_args --password=$password "
 [ -n "$db" ] && client_args="$client_args $db"
 
+log_debug "client_args: '$client_args'"
+
 ###########################################################################
 
 cur_attempt=1
 
 while true; do
 
+  log_debug "cur_attempt: $cur_attempt."
+
   if ( echo 'quit' | "$client_exe" $client_args >/dev/null 2>&1 ); then
-    echo "Success: server is ready to accept connection on socket."
-    exit 0
+    log_info "Success: server is ready to accept connection on socket."
+    quit 0
   fi
 
   [ $cur_attempt -ge $total_timeout ] && break
@@ -58,5 +90,5 @@ while true; do
 
 done
 
-echo "Error: server does not accept connections after $total_timeout seconds."
-exit 0
+log_error "Server does not accept connections after $total_timeout seconds."
+quit 0
diff --git a/sql/sql_cache.cc b/sql/sql_cache.cc
index 3362ec76fc2..a6e15c55641 100644
--- a/sql/sql_cache.cc
+++ b/sql/sql_cache.cc
@@ -737,7 +737,11 @@ void query_cache_end_of_result(THD *thd)
                            header->query()));
       query_cache.wreck(__LINE__, "");
 
-      BLOCK_UNLOCK_WR(query_block);
+      /*
+        We do not need call of BLOCK_UNLOCK_WR(query_block); here because
+        query_cache.wreck() switched query cache off but left content
+        untouched for investigation (it is debugging method).
+      */
       goto end;
     }
 #endif
@@ -3523,7 +3527,7 @@ uint Query_cache::filename_2_table_key (char *key, const char *path,
 
 #if defined(DBUG_OFF) && !defined(USE_QUERY_CACHE_INTEGRITY_CHECK)
 
-void wreck(uint line, const char *message) {}
+void wreck(uint line, const char *message) { query_cache_size = 0; }
 void bins_dump() {}
 void cache_dump() {}
 void queries_dump() {}
@@ -3535,6 +3539,17 @@ my_bool in_blocks(Query_cache_block * point) { return 0; }
 
 #else
 
+
+/*
+  Debug method which switch query cache off but left content for
+  investigation.
+
+  SYNOPSIS
+    Query_cache::wreck()
+    line                 line of the wreck() call
+    message              message for logging
+*/
+
 void Query_cache::wreck(uint line, const char *message)
 {
   THD *thd=current_thd;
diff --git a/sql/sql_trigger.cc b/sql/sql_trigger.cc
index 8baf84585b2..df648c49c09 100644
--- a/sql/sql_trigger.cc
+++ b/sql/sql_trigger.cc
@@ -107,7 +107,9 @@ const LEX_STRING trg_event_type_names[]=
 };
 
 
-static TABLE_LIST *add_table_for_trigger(THD *thd, sp_name *trig);
+static int
+add_table_for_trigger(THD *thd, sp_name *trig, bool if_exists,
+                      TABLE_LIST ** table);
 
 class Handle_old_incorrect_sql_modes_hook: public Unknown_key_hook
 {
@@ -156,6 +158,13 @@ private:
 */
 bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
 {
+  /*
+    FIXME: The code below takes too many different paths depending on the
+    'create' flag, so that the justification for a single function
+    'mysql_create_or_drop_trigger', compared to two separate functions
+    'mysql_create_trigger' and 'mysql_drop_trigger' is not apparent.
+    This is a good candidate for a minor refactoring.
+  */
   TABLE *table;
   bool result= TRUE;
   String stmt_query;
@@ -181,10 +190,6 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
     DBUG_RETURN(TRUE);
   }
 
-  if (!create &&
-      !(tables= add_table_for_trigger(thd, thd->lex->spname)))
-    DBUG_RETURN(TRUE);
-
   /*
     We don't allow creating triggers on tables in the 'mysql' schema
   */
@@ -194,9 +199,6 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
     DBUG_RETURN(TRUE);
   }
 
-  /* We should have only one table in table list. */
-  DBUG_ASSERT(tables->next_global == 0);
-
   /*
     Check that the user has TRIGGER privilege on the subject table.
   */
@@ -216,8 +218,10 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
   /*
     There is no DETERMINISTIC clause for triggers, so can't check it.
     But a trigger can in theory be used to do nasty things (if it supported
-    DROP for example) so we do the check for privileges. Triggers have the
-    same nature as functions regarding binlogging: their body is implicitely
+    DROP for example) so we do the check for privileges. For now there is
+    already a stronger test right above; but when this stronger test will
+    be removed, the test below will hold. Because triggers have the same
+    nature as functions regarding binlogging: their body is implicitly
     binlogged, so they share the same danger, so trust_function_creators
     applies to them too.
   */
@@ -228,24 +232,52 @@ bool mysql_create_or_drop_trigger(THD *thd, TABLE_LIST *tables, bool create)
     DBUG_RETURN(TRUE);
   }
 
-  /* We do not allow creation of triggers on temporary tables. */
-  if (create && find_temporary_table(thd, tables))
-  {
-    my_error(ER_TRG_ON_VIEW_OR_TEMP_TABLE, MYF(0), tables->alias);
-    DBUG_RETURN(TRUE);
-  }
-
   /*
     We don't want perform our operations while global read lock is held
-    so we have to wait until its end and then prevent it from occuring
+    so we have to wait until its end and then prevent it from occurring
     again until we are done. (Acquiring LOCK_open is not enough because
-    global read lock is held without helding LOCK_open).
+    global read lock is held without holding LOCK_open).
   */
   if (wait_if_global_read_lock(thd, 0, 1))
     DBUG_RETURN(TRUE);
 
   VOID(pthread_mutex_lock(&LOCK_open));
 
+  if (!create)
+  {
+    bool if_exists= thd->lex->drop_if_exists;
+
+    if (add_table_for_trigger(thd, thd->lex->spname, if_exists, & tables))
+      goto end;
+
+    if (!tables)
+    {
+      DBUG_ASSERT(if_exists);
+      /*
+        Since the trigger does not exist, there is no associated table,
+        and therefore :
+        - no TRIGGER privileges to check,
+        - no trigger to drop,
+        - no table to lock/modify,
+        so the drop statement is successful.
+      */
+      result= FALSE;
+      /* Still, we need to log the query ... */
+      stmt_query.append(thd->query, thd->query_length);
+      goto end;
+    }
+  }
+
+  /* We should have only one table in table list. */
+  DBUG_ASSERT(tables->next_global == 0);
+
+  /* We do not allow creation of triggers on temporary tables. */
+  if (create && find_temporary_table(thd, tables->db, tables->table_name))
+  {
+    my_error(ER_TRG_ON_VIEW_OR_TEMP_TABLE, MYF(0), tables->alias);
+    goto end;
+  }
+
   if (lock_table_names(thd, tables))
     goto end;
 
@@ -1141,13 +1173,17 @@ bool Table_triggers_list::get_trigger_info(THD *thd, trg_event_type event,
     mysql_table_for_trigger()
       thd    - current thread context
       trig   - identifier for trigger
+      if_exists - treat a not existing trigger as a warning if TRUE
+      table - pointer to TABLE_LIST object for the table trigger (output)
 
   RETURN VALUE
-    0 - error
-    # - pointer to TABLE_LIST object for the table
+    0 Success
+    1 Error
 */
 
-static TABLE_LIST *add_table_for_trigger(THD *thd, sp_name *trig)
+static int
+add_table_for_trigger(THD *thd, sp_name *trig, bool if_exists,
+                      TABLE_LIST **table)
 {
   LEX *lex= thd->lex;
   char path_buff[FN_REFLEN];
@@ -1158,6 +1194,7 @@ static TABLE_LIST *add_table_for_trigger(THD *thd, sp_name *trig)
                                           path_buff, &trigname.trigger_table);
   
   DBUG_ENTER("add_table_for_trigger");
+  DBUG_ASSERT(table != NULL);
 
   path.length= build_table_filename(path_buff, FN_REFLEN-1,
                                     trig->m_db.str, trig->m_name.str,
@@ -1166,30 +1203,45 @@ static TABLE_LIST *add_table_for_trigger(THD *thd, sp_name *trig)
 
   if (access(path_buff, F_OK))
   {
+    if (if_exists)
+    {
+      push_warning_printf(thd,
+                         MYSQL_ERROR::WARN_LEVEL_NOTE,
+                         ER_TRG_DOES_NOT_EXIST,
+                         ER(ER_TRG_DOES_NOT_EXIST));
+      *table= NULL;
+      DBUG_RETURN(0);
+    }
+
     my_error(ER_TRG_DOES_NOT_EXIST, MYF(0));
-    DBUG_RETURN(0);
+    DBUG_RETURN(1);
   }
 
   if (!(parser= sql_parse_prepare(&path, thd->mem_root, 1)))
-    DBUG_RETURN(0);
+    DBUG_RETURN(1);
 
   if (!is_equal(&trigname_file_type, parser->type()))
   {
     my_error(ER_WRONG_OBJECT, MYF(0), trig->m_name.str, trigname_file_ext+1,
              "TRIGGERNAME");
-    DBUG_RETURN(0);
+    DBUG_RETURN(1);
   }
 
   if (parser->parse((gptr)&trigname, thd->mem_root,
                     trigname_file_parameters, 1,
                     &trigger_table_hook))
-    DBUG_RETURN(0);
+    DBUG_RETURN(1);
 
   /* We need to reset statement table list to be PS/SP friendly. */
   lex->query_tables= 0;
   lex->query_tables_last= &lex->query_tables;
-  DBUG_RETURN(sp_add_to_query_tables(thd, lex, trig->m_db.str,
-                                     trigname.trigger_table.str, TL_IGNORE));
+  *table= sp_add_to_query_tables(thd, lex, trig->m_db.str,
+                                 trigname.trigger_table.str, TL_IGNORE);
+
+  if (! *table)
+    DBUG_RETURN(1);
+
+  DBUG_RETURN(0);
 }
 
 
diff --git a/sql/sql_yacc.yy b/sql/sql_yacc.yy
index c58d815ac22..ec3094ca721 100644
--- a/sql/sql_yacc.yy
+++ b/sql/sql_yacc.yy
@@ -7741,11 +7741,12 @@ drop:
             Lex->spname= $4;
             Lex->sql_command = SQLCOM_DROP_EVENT;
           }
-        | DROP TRIGGER_SYM sp_name
+        | DROP TRIGGER_SYM if_exists sp_name
           {
             LEX *lex= Lex;
             lex->sql_command= SQLCOM_DROP_TRIGGER;
-            lex->spname= $3;
+            lex->drop_if_exists= $3;
+            lex->spname= $4;
 	  }
         | DROP TABLESPACE tablespace_name opt_ts_engine opt_ts_wait
           {
@@ -7756,7 +7757,7 @@ drop:
           {
             LEX *lex= Lex;
             lex->alter_tablespace_info->ts_cmd_type= DROP_LOGFILE_GROUP;
-          }
+         }
 	;
 
 table_list: