fix for bug#16537 (Events: mysql.event.starts is null)

- now when the event is created and STARTS is omitted then STARTS is implicitly
  CURRENT_TIMESTAMP
- This CS also fixed incorrect presentation of STARTS/ENDS in I_S.EVENTS
(incorporated review changes)


mysql-test/r/events.result:
  results of new test cases
mysql-test/t/events.test:
  new test cases for bug #16537 (Events: mysql.event.starts is null)
sql/event.cc:
  - check whether event_timed::starts_null only in case
    event_timed::expression is set, so for recurring events only
  - disable binlogging of CREATE EVENT statement. It should not be
    replicated but the result of the execution. Still the replication is
    untouched topic.
sql/event.h:
  - add flags whether starts, ends and execute_at are null or not
sql/event_executor.cc:
  - check whether xxx_null instead of !xxxx.year
sql/event_timed.cc:
  - introduce xxx_null and change the usage of xxx.year to !xxx_null
sql/sql_show.cc:
  - don't show 0000-00-00 in I_S.EVENTS when the value is NULL
sql/sql_yacc.yy:
  - if STARTS is omitted default to current_timestamp

mysql-test/r/events.result

@@ -13,6 +13,54 @@ alter event event3 rename to event2;
 drop event event2;
 create event event2 on schedule every 2 second starts now() ends date_add(now(), interval 5 hour) comment "some" DO begin end;
 drop event event2;
+CREATE EVENT event_starts_test ON SCHEDULE EVERY 10 SECOND COMMENT "" DO SELECT 1;
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	10	INTERVAL_SECOND	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+0	1	
+ALTER EVENT event_starts_test ON SCHEDULE AT '2020-02-02 20:00:02';
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	ONE TIME	2020-02-02 17:00:02	NULL	NULL	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+1	1	
+ALTER EVENT event_starts_test COMMENT "non-empty comment";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	ONE TIME	2020-02-02 17:00:02	NULL	NULL	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+1	1	non-empty comment
+ALTER EVENT event_starts_test COMMENT "";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	ONE TIME	2020-02-02 17:00:02	NULL	NULL	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+1	1	
+DROP EVENT event_starts_test;
+CREATE EVENT event_starts_test ON SCHEDULE EVERY 20 SECOND STARTS '2020-02-02 20:00:02' ENDS '2022-02-02 20:00:02' DO SELECT 2;
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	20	INTERVAL_SECOND	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+0	0	
+ALTER EVENT event_starts_test COMMENT "non-empty comment";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	20	INTERVAL_SECOND	#	#	ENABLED
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+starts IS NULL	ends IS NULL	comment
+0	0	non-empty comment
+ALTER EVENT event_starts_test COMMENT "";
+SHOW EVENTS;
+Db	Name	Definer	Type	Execute at	Interval value	Interval field	Starts	Ends	Status
+events_test	event_starts_test	root@localhost	RECURRING	NULL	20	INTERVAL_SECOND	#	#	ENABLED
+DROP EVENT event_starts_test;
 create event e_43 on schedule every 1 second do set @a = 5;
 set global event_scheduler = 1;
 select sleep(2);
@@ -64,7 +112,7 @@ SHOW GRANTS;
 Grants for ev_test@localhost
 GRANT USAGE ON *.* TO 'ev_test'@'localhost'
 GRANT ALL PRIVILEGES ON `events_test`.* TO 'ev_test'@'localhost'
-GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, REFERENCES, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE ON `events_test2`.* TO 'ev_test'@'localhost'
+GRANT SELECT, INSERT, UPDATE, DELETE, CREATE, DROP, REFERENCES, INDEX, ALTER, CREATE TEMPORARY TABLES, LOCK TABLES, EXECUTE, CREATE VIEW, SHOW VIEW, CREATE ROUTINE, ALTER ROUTINE, TRIGGER ON `events_test2`.* TO 'ev_test'@'localhost'
 "Here comes an error:";
 SHOW EVENTS;
 ERROR 42000: Access denied for user 'ev_test'@'localhost' to database 'events_test2'

mysql-test/t/events.test

@@ -15,6 +15,38 @@ drop event event2;
 create event event2 on schedule every 2 second starts now() ends date_add(now(), interval 5 hour) comment "some" DO begin end;
 drop event event2;
 
+# BUG #16537 (Events: mysql.event.starts is null)
+CREATE EVENT event_starts_test ON SCHEDULE EVERY 10 SECOND COMMENT "" DO SELECT 1;
+--replace_column 8 # 9 #
+SHOW EVENTS;
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+ALTER EVENT event_starts_test ON SCHEDULE AT '2020-02-02 20:00:02';
+--replace_column 8 # 9 #
+SHOW EVENTS;
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+ALTER EVENT event_starts_test COMMENT "non-empty comment";
+--replace_column 8 # 9 #
+SHOW EVENTS;
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+ALTER EVENT event_starts_test COMMENT "";
+--replace_column 8 # 9 #
+SHOW EVENTS;
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+DROP EVENT event_starts_test;
+CREATE EVENT event_starts_test ON SCHEDULE EVERY 20 SECOND STARTS '2020-02-02 20:00:02' ENDS '2022-02-02 20:00:02' DO SELECT 2;
+--replace_column 8 # 9 #
+SHOW EVENTS;
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+ALTER EVENT event_starts_test COMMENT "non-empty comment";
+--replace_column 8 # 9 #
+SHOW EVENTS;
+SELECT starts IS NULL, ends IS NULL, comment FROM mysql.event WHERE db='events_test' AND name='event_starts_test';
+ALTER EVENT event_starts_test COMMENT "";
+--replace_column 8 # 9 #
+SHOW EVENTS;
+DROP EVENT event_starts_test;
+#
+#
 create event e_43 on schedule every 1 second do set @a = 5;
 set global event_scheduler = 1;
 select sleep(2);

sql/event.cc

@@ -273,20 +273,6 @@ evex_fill_row(THD *thd, TABLE *table, event_timed *et, my_bool is_update)
                      store(et->body.str, et->body.length, system_charset_info))
       goto trunc_err;
 
-  if (et->starts.year)
-  {
-    table->field[EVEX_FIELD_STARTS]->set_notnull();// set NULL flag to OFF
-    table->field[EVEX_FIELD_STARTS]->
-                          store_time(&et->starts, MYSQL_TIMESTAMP_DATETIME);
-  }	   
-
-  if (et->ends.year)
-  {
-    table->field[EVEX_FIELD_ENDS]->set_notnull();
-    table->field[EVEX_FIELD_ENDS]->
-                          store_time(&et->ends, MYSQL_TIMESTAMP_DATETIME);
-  }
-   
   if (et->expression)
   {
     table->field[EVEX_FIELD_INTERVAL_EXPR]->set_notnull();
@@ -300,18 +286,31 @@ evex_fill_row(THD *thd, TABLE *table, event_timed *et, my_bool is_update)
     table->field[EVEX_FIELD_TRANSIENT_INTERVAL]->store((longlong)et->interval+1);
 
     table->field[EVEX_FIELD_EXECUTE_AT]->set_null();
+
+    if (!et->starts_null)
+    {
+      table->field[EVEX_FIELD_STARTS]->set_notnull();// set NULL flag to OFF
+      table->field[EVEX_FIELD_STARTS]->
+                            store_time(&et->starts, MYSQL_TIMESTAMP_DATETIME);
+    }	   
+
+    if (!et->ends_null)
+    {
+      table->field[EVEX_FIELD_ENDS]->set_notnull();
+      table->field[EVEX_FIELD_ENDS]->
+                            store_time(&et->ends, MYSQL_TIMESTAMP_DATETIME);
+    }
   }
   else if (et->execute_at.year)
   {
-    // fix_fields already called in init_execute_at
     table->field[EVEX_FIELD_INTERVAL_EXPR]->set_null();
     table->field[EVEX_FIELD_TRANSIENT_INTERVAL]->set_null();
-
+    table->field[EVEX_FIELD_STARTS]->set_null();
+    table->field[EVEX_FIELD_ENDS]->set_null();
+    
     table->field[EVEX_FIELD_EXECUTE_AT]->set_notnull();
     table->field[EVEX_FIELD_EXECUTE_AT]->store_time(&et->execute_at,
                                                     MYSQL_TIMESTAMP_DATETIME);    
-    
-    table->field[EVEX_FIELD_TRANSIENT_INTERVAL]->set_null();  
   }
   else
   {
@@ -322,14 +321,17 @@ evex_fill_row(THD *thd, TABLE *table, event_timed *et, my_bool is_update)
     
   ((Field_timestamp *)table->field[EVEX_FIELD_MODIFIED])->set_time();
 
-  if (et->comment.length)
-    if (table->field[field_num= EVEX_FIELD_COMMENT]->
-	store(et->comment.str, et->comment.length, system_charset_info))
+  if (et->comment.str)
+  {
+    if (table->field[field_num= EVEX_FIELD_COMMENT]->store(et->comment.str,
+                                                           et->comment.length,
+                                                           system_charset_info))
       goto trunc_err;
+  }
 
   DBUG_RETURN(0);
 trunc_err:
-  my_error(ER_EVENT_DATA_TOO_LONG, MYF(0));
+  my_error(ER_EVENT_DATA_TOO_LONG, MYF(0), table->field[field_num]->field_name);
   DBUG_RETURN(EVEX_GENERAL_ERROR);
 }
 
@@ -442,14 +444,16 @@ db_create_event(THD *thd, event_timed *et, my_bool create_if_not,
     my_error(ER_EVENT_STORE_FAILED, MYF(0), et->name.str, ret);
     goto err;
   }
-  
+
+#ifdef USE_THIS_CODE_AS_TEMPLATE_WHEN_EVENT_REPLICATION_IS_AGREED   
   if (mysql_bin_log.is_open())
   {
     thd->clear_error();
-    /* Such a statement can always go directly to binlog, no trans cache */
+    // Such a statement can always go directly to binlog, no trans cache
     thd->binlog_query(THD::MYSQL_QUERY_TYPE,
                       thd->query, thd->query_length, FALSE, FALSE);
   }
+#endif
   
   *rows_affected= 1;
 ok:

sql/event.h

@@ -100,6 +100,9 @@ class event_timed
   TIME starts;
   TIME ends;
   TIME execute_at;
+  my_bool starts_null;
+  my_bool ends_null;
+  my_bool execute_at_null;
 
   longlong expression;
   interval_type interval;

sql/event_executor.cc

@@ -203,7 +203,7 @@ event_executor_main(void *arg)
 
   if (init_event_thread(thd))
     goto err;
-  
+
   // make this thread invisible it has no vio -> show processlist won't see
   thd->system_thread= 1;
 
@@ -321,8 +321,7 @@ event_executor_main(void *arg)
     et= evex_queue_first_element(&EVEX_EQ_NAME, event_timed*);
     DBUG_PRINT("evex main thread",("got event from the queue"));
       
-    if (et->execute_at.year > 1969 &&
-        my_time_compare(&time_now, &et->execute_at) == -1)
+    if (!et->execute_at_null && my_time_compare(&time_now,&et->execute_at) == -1)
     {
       DBUG_PRINT("evex main thread",("still not the time for execution"));
       VOID(pthread_mutex_unlock(&LOCK_event_arrays));
@@ -359,8 +358,11 @@ event_executor_main(void *arg)
 #else
       event_executor_worker((void *) et);
 #endif
-      if ((et->execute_at.year && !et->expression) ||
-           TIME_to_ulonglong_datetime(&et->execute_at) == 0)
+      /*
+        1. For one-time event : year is > 0 and expression is 0
+        2. For recurring, expression is != -=> check execute_at_null in this case
+      */
+      if ((et->execute_at.year && !et->expression) || et->execute_at_null)
          et->flags |= EVENT_EXEC_NO_MORE;
 
       if ((et->flags & EVENT_EXEC_NO_MORE) || et->status == MYSQL_EVENT_DISABLED)
@@ -481,9 +483,9 @@ event_executor_worker(void *event_void)
 #endif
 
   // thd->security_ctx->priv_host is char[MAX_HOSTNAME]
-  
+
   strxnmov(thd->security_ctx->priv_host, sizeof(thd->security_ctx->priv_host),
-                event->definer_host.str, NullS);  
+                event->definer_host.str, NullS);
 
   thd->security_ctx->user= thd->security_ctx->priv_user=
                              my_strdup(event->definer_user.str, MYF(0));
@@ -506,7 +508,6 @@ event_executor_worker(void *event_void)
     if (ret == EVEX_COMPILE_ERROR)
       sql_print_information("    EVEX COMPILE ERROR for event %s.%s",
                              event->dbname.str, event->name.str);
-    
     DBUG_PRINT("info", ("    EVEX EXECUTED event %s.%s  [EXPR:%d]. RetCode=%d",
                         event->dbname.str, event->name.str,
                         (int) event->expression, ret));

sql/sql_show.cc

@@ -3883,35 +3883,32 @@ fill_events_copy_to_schema_table(THD *thd, TABLE *sch_table, TABLE *event_table)
   {
     //type
     sch_table->field[5]->store(STRING_WITH_LEN("RECURRING"), scs);
-    //execute_at
-    sch_table->field[6]->set_null();
     //interval_value
     sch_table->field[7]->set_notnull();
     sch_table->field[7]->store((longlong) et.expression);
+
     //interval_type
     LEX_STRING *ival=&interval_type_to_name[get_real_interval_type(et.interval)];
     sch_table->field[8]->set_notnull();
     sch_table->field[8]->store(ival->str, ival->length, scs);
-    //starts & ends
+
+    //starts & ends    
     sch_table->field[10]->set_notnull();
     sch_table->field[10]->store_time(&et.starts, MYSQL_TIMESTAMP_DATETIME);
-    sch_table->field[11]->set_notnull();
-    sch_table->field[11]->store_time(&et.ends, MYSQL_TIMESTAMP_DATETIME);
+
+    if (!et.ends_null)
+    {
+      sch_table->field[11]->set_notnull();
+      sch_table->field[11]->store_time(&et.ends, MYSQL_TIMESTAMP_DATETIME);
+    }
   }
   else
   {
     //type
     sch_table->field[5]->store(STRING_WITH_LEN("ONE TIME"), scs);
-    //execute_at
+
     sch_table->field[6]->set_notnull();
     sch_table->field[6]->store_time(&et.execute_at, MYSQL_TIMESTAMP_DATETIME);
-    //interval
-    sch_table->field[7]->set_null();
-    //interval_type
-    sch_table->field[8]->set_null();
-    //starts & ends
-    sch_table->field[10]->set_null();
-    sch_table->field[11]->set_null();
   }
 
   //status

sql/sql_yacc.yy

@@ -1475,6 +1475,9 @@ opt_ev_status: /* empty */ {$<ulong_num>$= 0;}
       ;
 
 ev_starts: /* empty */
+          {
+            Lex->et->init_starts(YYTHD, new Item_func_now_local());
+          }
         | STARTS_SYM expr
           {
             LEX *lex= Lex;