diff --git a/mysql-test/main/signal.result b/mysql-test/main/signal.result
index 905842bfb1cff..215f7db8b0d8a 100644
--- a/mysql-test/main/signal.result
+++ b/mysql-test/main/signal.result
@@ -1132,7 +1132,7 @@ DECLARE hhhx VARCHAR(65);
 DECLARE iiix VARCHAR(65);
 DECLARE jjjx VARCHAR(65);
 DECLARE kkkx VARCHAR(65);
-DECLARE lllx VARCHAR(129);
+DECLARE lllx VARCHAR(513);
 DECLARE warn CONDITION FOR SQLSTATE "01234";
 set aaax= concat(repeat("A", 64), "X");
 set bbbx= concat(repeat("B", 64), "X");
@@ -1145,9 +1145,9 @@ set hhhx= concat(repeat("H", 64), "X");
 set iiix= concat(repeat("I", 64), "X");
 set jjjx= concat(repeat("J", 64), "X");
 set kkkx= concat(repeat("K", 64), "X");
-set lllx= concat(repeat("1", 100),
-repeat("2", 20),
-repeat("8", 8),
+set lllx= concat(repeat("1", 500),
+repeat("2", 10),
+repeat("8", 2),
 "X");
 SIGNAL warn SET
 CLASS_ORIGIN = aaax,
@@ -1176,7 +1176,7 @@ Warning	1647	Data truncated for condition item 'TABLE_NAME'
 Warning	1647	Data truncated for condition item 'COLUMN_NAME'
 Warning	1647	Data truncated for condition item 'CURSOR_NAME'
 Warning	1647	Data truncated for condition item 'MESSAGE_TEXT'
-Warning	10000	11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111112222222222222222222288888888
+Warning	10000	11111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111222222222288
 drop procedure test_signal $$
 set sql_mode = DEFAULT $$
 create procedure test_signal()
diff --git a/mysql-test/main/signal.test b/mysql-test/main/signal.test
index cdb5796f1da4a..e4dcb5a71cfa0 100644
--- a/mysql-test/main/signal.test
+++ b/mysql-test/main/signal.test
@@ -1360,7 +1360,7 @@ begin
   DECLARE iiix VARCHAR(65);
   DECLARE jjjx VARCHAR(65);
   DECLARE kkkx VARCHAR(65);
-  DECLARE lllx VARCHAR(129);
+  DECLARE lllx VARCHAR(513);
 
   DECLARE warn CONDITION FOR SQLSTATE "01234";
 
@@ -1375,9 +1375,9 @@ begin
   set iiix= concat(repeat("I", 64), "X");
   set jjjx= concat(repeat("J", 64), "X");
   set kkkx= concat(repeat("K", 64), "X");
-  set lllx= concat(repeat("1", 100),
-                   repeat("2", 20),
-                   repeat("8", 8),
+  set lllx= concat(repeat("1", 500),
+                   repeat("2", 10),
+                   repeat("8", 2),
                    "X");
 
   SIGNAL warn SET
diff --git a/mysql-test/main/signal_sqlmode.result b/mysql-test/main/signal_sqlmode.result
index 8fed85eb4a93d..db7ac68041caa 100644
--- a/mysql-test/main/signal_sqlmode.result
+++ b/mysql-test/main/signal_sqlmode.result
@@ -36,7 +36,7 @@ Warning	1265	Data truncated for column 'utf8_var' at row 1
 call p2;
 length(msg)	msg
 129	AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAX
-ERROR 55555: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA
+ERROR 55555: AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAX
 call p3;
 length(name)	name
 65	AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAX
@@ -54,8 +54,8 @@ end
 $$
 create procedure p2()
 begin
-declare msg VARCHAR(129) CHARACTER SET UTF8;
-set msg = concat(repeat('A', 128), 'X');
+declare msg VARCHAR(513) CHARACTER SET UTF8;
+set msg = concat(repeat('A', 512), 'X');
 select length(msg), msg;
 signal sqlstate '55555' set message_text = msg;
 end
@@ -74,7 +74,7 @@ call p;
 ERROR 22001: Data too long for column 'utf8_var' at row 1
 call p2;
 length(msg)	msg
-129	AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAX
+513	AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAX
 ERROR HY000: Data too long for condition item 'MESSAGE_TEXT'
 call p3;
 length(name)	name
diff --git a/mysql-test/main/signal_sqlmode.test b/mysql-test/main/signal_sqlmode.test
index 2b311fd1ab1c1..d4143c0fe7414 100644
--- a/mysql-test/main/signal_sqlmode.test
+++ b/mysql-test/main/signal_sqlmode.test
@@ -69,8 +69,8 @@ $$
 
 create procedure p2()
 begin
-  declare msg VARCHAR(129) CHARACTER SET UTF8;
-  set msg = concat(repeat('A', 128), 'X');
+  declare msg VARCHAR(513) CHARACTER SET UTF8;
+  set msg = concat(repeat('A', 512), 'X');
   select length(msg), msg;
 
   signal sqlstate '55555' set message_text = msg;
diff --git a/sql/sql_signal.cc b/sql/sql_signal.cc
index 1da8b1451517a..e1d9dcad57b42 100644
--- a/sql/sql_signal.cc
+++ b/sql/sql_signal.cc
@@ -262,12 +262,13 @@ int Sql_cmd_common_signal::eval_signal_informations(THD *thd, Sql_condition *con
     }
     /*
       Enforce that SET MESSAGE_TEXT = <value> evaluates the value
-      as VARCHAR(128) CHARACTER SET UTF8.
+      as VARCHAR(MYSQL_ERRMSG_SIZE) CHARACTER SET UTF8.
     */
     bool truncated;
     String utf8_text;
     str= set->val_str(& str_value);
-    truncated= assign_fixed_string(thd->mem_root, & my_charset_utf8_bin, 128,
+    truncated= assign_fixed_string(thd->mem_root, & my_charset_utf8_bin,
+                                   MYSQL_ERRMSG_SIZE,
                                    & utf8_text, str);
     if (truncated)
     {