diff --git a/include/json_lib.h b/include/json_lib.h
index 7de7f2827518f..d97f0a6ca341e 100644
--- a/include/json_lib.h
+++ b/include/json_lib.h
@@ -2,6 +2,7 @@
 #define JSON_LIB_INCLUDED
 
 #include <my_sys.h>
+#include <stdint.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -228,7 +229,7 @@ typedef struct st_json_engine_t
 
   int stack[JSON_DEPTH_LIMIT]; /* Keeps the stack of nested JSON structures. */
   int stack_p;                 /* The 'stack' pointer. */
-  volatile uchar *killed_ptr;
+  volatile uint8_t *killed_ptr;
 } json_engine_t;
 
 
diff --git a/mysql-test/main/func_json_notembedded.result b/mysql-test/main/func_json_notembedded.result
index ba4d38dd623f3..19267ef1e1686 100644
--- a/mysql-test/main/func_json_notembedded.result
+++ b/mysql-test/main/func_json_notembedded.result
@@ -11,7 +11,7 @@ length(@obj)	length(@arr)
 5000009	5000009
 set max_statement_time=0.0001;
 SET @old_debug= @@debug_dbug;
-SET debug_dbug='+d,debug_max_statement_time exceeded';
+SET debug_dbug='+d,json_pause_execution';
 select json_array_append(@arr, '$[0]', 1);
 ERROR 70100: Query execution was interrupted (max_statement_time exceeded)
 select json_array_insert(@arr, '$[0]', 1);
diff --git a/mysql-test/main/func_json_notembedded.test b/mysql-test/main/func_json_notembedded.test
index 1e05571e16f83..f147190e53122 100644
--- a/mysql-test/main/func_json_notembedded.test
+++ b/mysql-test/main/func_json_notembedded.test
@@ -18,7 +18,7 @@ select length(@obj), length(@arr);
 set max_statement_time=0.0001;
 disable_abort_on_error;
 SET @old_debug= @@debug_dbug;
-SET debug_dbug='+d,debug_max_statement_time exceeded';
+SET debug_dbug='+d,json_pause_execution';
 select json_array_append(@arr, '$[0]', 1);
 select json_array_insert(@arr, '$[0]', 1);
 select json_insert(@obj, '$.meta', 1);
diff --git a/sql/item_jsonfunc.cc b/sql/item_jsonfunc.cc
index 7ee9933a0efde..54ce0308d0b6f 100644
--- a/sql/item_jsonfunc.cc
+++ b/sql/item_jsonfunc.cc
@@ -2119,7 +2119,7 @@ String *Item_func_json_array_append::val_str(String *str)
 
     json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                     (const uchar *) js->ptr() + js->length());
-    je.killed_ptr= (uchar*)&thd->killed;
+    je.killed_ptr= (volatile uint8_t*) (uchar*)&thd->killed;
 
     c_path->cur_step= c_path->p.steps;
 
@@ -2200,7 +2200,7 @@ String *Item_func_json_array_append::val_str(String *str)
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
-  je.killed_ptr= (uchar*)&thd->killed;
+  je.killed_ptr= (volatile uint8_t*) &thd->killed;
   if (json_nice(&je, str, Item_func_json_format::LOOSE))
     goto js_error;
 
@@ -2208,9 +2208,9 @@ String *Item_func_json_array_append::val_str(String *str)
 
 js_error:
   report_json_error(js, &je, 0);
+  thd->check_killed(); // to get the error message right
 
 return_null:
-  thd->check_killed(); // to get the error message right
   null_value= 1;
   return 0;
 }
@@ -2263,7 +2263,7 @@ String *Item_func_json_array_insert::val_str(String *str)
 
     json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                     (const uchar *) js->ptr() + js->length());
-    je.killed_ptr= (uchar*)&thd->killed;
+    je.killed_ptr= (volatile uint8_t*) &thd->killed;
 
     c_path->cur_step= c_path->p.steps;
 
@@ -2399,7 +2399,7 @@ String *Item_func_json_array_insert::val_str(String *str)
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
-  je.killed_ptr= (uchar*)&thd->killed;
+  je.killed_ptr= (volatile uint8_t*) (uchar*)&thd->killed;
   if (json_nice(&je, str, Item_func_json_format::LOOSE))
     goto js_error;
 
@@ -2690,11 +2690,11 @@ String *Item_func_json_merge::val_str(String *str)
 
     json_scan_start(&je1, js1->charset(),(const uchar *) js1->ptr(),
                     (const uchar *) js1->ptr() + js1->length());
-    je1.killed_ptr= (uchar*)&thd->killed;
+    je1.killed_ptr= (volatile uint8_t*) (uchar*)&thd->killed;
 
     json_scan_start(&je2, js2->charset(),(const uchar *) js2->ptr(),
                     (const uchar *) js2->ptr() + js2->length());
-    je2.killed_ptr= (uchar*)&thd->killed;
+    je2.killed_ptr= (volatile uint8_t*) (uchar*)&thd->killed;
 
     if (do_merge(str, &je1, &je2))
       goto error_return;
@@ -2716,7 +2716,8 @@ String *Item_func_json_merge::val_str(String *str)
 
   json_scan_start(&je1, js1->charset(),(const uchar *) js1->ptr(),
                   (const uchar *) js1->ptr() + js1->length());
-  je1.killed_ptr= (uchar*)&thd->killed;
+  je1.killed_ptr= (volatile uint8_t*) (uchar*)&thd->killed;
+
   if (json_nice(&je1, str, Item_func_json_format::LOOSE))
     goto error_return;
 
@@ -2823,6 +2824,7 @@ static int do_merge_patch(String *str, json_engine_t *je1, json_engine_t *je2,
 
     if (str->append('{'))
       return 3;
+
     while (json_scan_next(je1) == 0 &&
            je1->state != JST_OBJ_END)
     {
@@ -3002,7 +3004,7 @@ String *Item_func_json_merge_patch::val_str(String *str)
 
     json_scan_start(&je2, js2->charset(),(const uchar *) js2->ptr(),
                     (const uchar *) js2->ptr() + js2->length());
-    je2.killed_ptr= (uchar*)&thd->killed;
+    je2.killed_ptr= (volatile uint8_t*) &thd->killed;
 
     if (merge_to_null)
     {
@@ -3022,7 +3024,7 @@ String *Item_func_json_merge_patch::val_str(String *str)
 
     json_scan_start(&je1, js1->charset(),(const uchar *) js1->ptr(),
                     (const uchar *) js1->ptr() + js1->length());
-    je1.killed_ptr= (uchar*)&thd->killed;
+    je1.killed_ptr= (volatile uint8_t*) &thd->killed;
 
     if (do_merge_patch(str, &je1, &je2, &empty_result))
       goto error_return;
@@ -3051,7 +3053,7 @@ String *Item_func_json_merge_patch::val_str(String *str)
 
   json_scan_start(&je1, js1->charset(),(const uchar *) js1->ptr(),
                   (const uchar *) js1->ptr() + js1->length());
-  je1.killed_ptr= (uchar*)&thd->killed;
+  je1.killed_ptr= (volatile uint8_t*) &thd->killed;
   if (json_nice(&je1, str, Item_func_json_format::LOOSE))
     goto error_return;
 
@@ -3093,6 +3095,7 @@ longlong Item_func_json_length::val_int()
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
+  je.killed_ptr= (volatile uint8_t*) &current_thd->killed;
 
   if (arg_count > 1)
   {
@@ -3158,6 +3161,7 @@ longlong Item_func_json_length::val_int()
 
 err_return:
   report_json_error(js, &je, 0);
+  current_thd->check_killed(); // to get the error message right
 null_return:
   null_value= 1;
   return 0;
@@ -3177,6 +3181,7 @@ longlong Item_func_json_depth::val_int()
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
+  je.killed_ptr= (volatile uint8_t*) &current_thd->killed;
 
   do
   {
@@ -3211,6 +3216,7 @@ longlong Item_func_json_depth::val_int()
     return depth;
 
   report_json_error(js, &je, 0);
+  current_thd->check_killed(); // to get the error message right
   null_value= 1;
   return 0;
 }
@@ -3237,6 +3243,7 @@ String *Item_func_json_type::val_str(String *str)
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
+  je.killed_ptr= (volatile uint8_t*) &current_thd->killed;
 
   if (json_read_value(&je))
     goto error;
@@ -3275,6 +3282,7 @@ String *Item_func_json_type::val_str(String *str)
 
 error:
   report_json_error(js, &je, 0);
+  current_thd->check_killed();
   null_value= 1;
   return 0;
 }
@@ -3355,7 +3363,7 @@ String *Item_func_json_insert::val_str(String *str)
 
     json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                     (const uchar *) js->ptr() + js->length());
-    je.killed_ptr= (uchar*)&thd->killed;
+    je.killed_ptr= (volatile uint8_t*) &thd->killed;
 
     if (c_path->p.last_step < c_path->p.steps)
       goto v_found;
@@ -3545,7 +3553,7 @@ String *Item_func_json_insert::val_str(String *str)
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
-  je.killed_ptr= (uchar*)&thd->killed;
+  je.killed_ptr= (volatile uint8_t*) &thd->killed;
   if (json_nice(&je, str, Item_func_json_format::LOOSE))
     goto js_error;
 
@@ -3626,7 +3634,7 @@ String *Item_func_json_remove::val_str(String *str)
 
     json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                     (const uchar *) js->ptr() + js->length());
-    je.killed_ptr= (uchar*)&thd->killed;
+    je.killed_ptr= (volatile uint8_t*) &thd->killed;
 
     c_path->cur_step= c_path->p.steps;
 
@@ -3747,7 +3755,7 @@ String *Item_func_json_remove::val_str(String *str)
 
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
-  je.killed_ptr= (uchar*)&thd->killed;
+  je.killed_ptr= (volatile uint8_t*) &thd->killed;
   if (json_nice(&je, str, Item_func_json_format::LOOSE))
     goto js_error;
 
@@ -4187,6 +4195,7 @@ String *Item_func_json_format::val_str(String *str)
   int tab_size= 4;
   THD *thd= current_thd;
 
+  JSON_DO_PAUSE_EXECUTION(thd, 0.0002);
   if ((null_value= args[0]->null_value))
     return 0;
 
@@ -4209,7 +4218,7 @@ String *Item_func_json_format::val_str(String *str)
 
   json_scan_start(&je, js->charset(), (const uchar *) js->ptr(),
                   (const uchar *) js->ptr()+js->length());
-  je.killed_ptr= (uchar*)&thd->killed;
+  je.killed_ptr= (volatile uint8_t*) &thd->killed;
 
   if (json_nice(&je, str, fmt, tab_size))
   {
@@ -4983,6 +4992,7 @@ bool Item_func_json_overlaps::val_bool()
     report_json_error(js, &je, 0);
   if (ve.s.error)
     report_json_error(val, &ve, 1);
+  current_thd->check_killed(); // to get the error message right
   return 0;
 }
 
diff --git a/sql/sql_class.h b/sql/sql_class.h
index aa78312c3b6a5..b3d589575cf32 100644
--- a/sql/sql_class.h
+++ b/sql/sql_class.h
@@ -613,7 +613,7 @@ extern const LEX_CSTRING Diag_condition_item_names[];
   These states are bit coded with HARD. For each state there must be a pair
   <state_even_num>, and <state_odd_num>_HARD.
 */
-enum killed_state
+enum killed_state : uint8_t
 {
   NOT_KILLED= 0,
   KILL_HARD_BIT= 1,                             /* Bit for HARD KILL */
diff --git a/strings/json_lib.c b/strings/json_lib.c
index bce0e264f32ab..0c7b0fb25737d 100644
--- a/strings/json_lib.c
+++ b/strings/json_lib.c
@@ -807,13 +807,13 @@ static json_state_handler json_actions[NR_JSON_STATES][NR_C_CLASSES]=
 int json_scan_start(json_engine_t *je,
                     CHARSET_INFO *i_cs, const uchar *str, const uchar *end)
 {
-  static const uchar no_time_to_die= 0;
+  static const uint8_t no_time_to_die= 0;
 
   json_string_setup(&je->s, i_cs, str, end);
   je->stack[0]= JST_DONE;
   je->stack_p= 0;
   je->state= JST_VALUE;
-  je->killed_ptr = (uchar*)&no_time_to_die;
+  je->killed_ptr=  (uint8 *) &no_time_to_die;
   return 0;
 }