Bug#28141: Control C on query waiting on lock causes ERROR 1053 (server shutdown)

If a thread is killed in the server, we throw "shutdown" only if one is actually in
progress; otherwise, we throw "query interrupted".

Control-C in the mysql command-line client is "incremental" now.
First Control-C sends KILL QUERY (when connected to 5.0+ server, otherwise, see next)
Next  Control-C sends KILL CONNECTION
Next  Control-C aborts client.

As the first two steps only pertain to an existing query,
Control-C will abort the client right away if no query is running.

client will give more detailed/consistent feedback on Control-C now.


client/mysql.cc:
  Extends Control-C handling; enhances up feedback to user.
  
  On 5.0+ servers, we try to be nice and send KILL QUERY first
  if Control-C is pressed in the command-line client, but if
  that doesn't work, we now give the user the opportunity to
  send KILL CONNECTION with another Control-C (and to kill the
  client with another Control-C if that somehow doesn't work
  either).
mysql-test/t/flush_read_lock_kill.test:
  we're getting correct "thread killed" rather than
  "in shutdown" error now
mysql-test/t/kill.test:
  we're getting correct "thread killed" rather than
  "in shutdown" error now
mysql-test/t/rpl000001.test:
  we're getting correct "thread killed" rather than
  "in shutdown" error now
mysql-test/t/rpl_error_ignored_table.test:
  we're getting correct "thread killed" rather than
  "in shutdown" error now
sql/records.cc:
  make error messages on KILL uniform for rr_*()
  by folding that handling into rr_handle_error()
sql/sql_class.h:
  Only throw "shutdown" when we have one flagged as being in progress;
  otherwise, throw "query interrupted" as it's likely to be "KILL CONNECTION"
  or related.

client/mysql.cc

@@ -1219,18 +1219,34 @@ sig_handler mysql_sigint(int sig)
   MYSQL *kill_mysql= NULL;
 
   /* terminate if no query being executed, or we already tried interrupting */
-  if (!executing_query || interrupted_query++)
+  if (!executing_query || (interrupted_query == 2))
+  {
+    tee_fprintf(stdout, "Ctrl-C -- exit!\n");
     goto err;
+  }
 
   kill_mysql= mysql_init(kill_mysql);
   if (!mysql_real_connect(kill_mysql,current_host, current_user, opt_password,
                           "", opt_mysql_port, opt_mysql_unix_port,0))
+  {
+    tee_fprintf(stdout, "Ctrl-C -- sorry, cannot connect to server to kill query, giving up ...\n");
     goto err;
+  }
+
+  interrupted_query++;
+
+  /* mysqld < 5 does not understand KILL QUERY, skip to KILL CONNECTION */
+  if ((interrupted_query == 1) && (mysql_get_server_version(&mysql) < 50000))
+    interrupted_query= 2;
+
   /* kill_buffer is always big enough because max length of %lu is 15 */
-  sprintf(kill_buffer, "KILL /*!50000 QUERY */ %lu", mysql_thread_id(&mysql));
+  sprintf(kill_buffer, "KILL %s%lu",
+          (interrupted_query == 1) ? "QUERY " : "",
+          mysql_thread_id(&mysql));
+  tee_fprintf(stdout, "Ctrl-C -- sending \"%s\" to server ...\n", kill_buffer);
   mysql_real_query(kill_mysql, kill_buffer, (uint) strlen(kill_buffer));
   mysql_close(kill_mysql);
-  tee_fprintf(stdout, "Query aborted by Ctrl+C\n");
+  tee_fprintf(stdout, "Ctrl-C -- query aborted.\n");
 
   return;
 

mysql-test/t/flush_read_lock_kill.test

@@ -50,7 +50,7 @@ connection con1;
 # debug build running without our --debug=make_global..., will be
 # error 0 (no error). The only important thing to test is that on
 # debug builds with our --debug=make_global... we don't hang forever.
---error 0,1053,2013
+--error 0,1317,2013
 reap;
 
 connection con2;

mysql-test/t/kill.test

@@ -92,7 +92,7 @@ select ((@id := kill_id) - kill_id) from t3;
 kill @id;
 
 connection conn1;
--- error 1053,2013
+-- error 1317,2013
 reap;
 
 connection default;

mysql-test/t/rpl000001.test

@@ -92,7 +92,7 @@ kill @id;
 # We don't drop t3 as this is a temporary table
 drop table t2;
 connection master;
---error 1053,2013
+--error 1317,2013
 reap;
 connection slave;
 # The SQL slave thread should now have stopped because the query was killed on

mysql-test/t/rpl_error_ignored_table.test

@@ -45,7 +45,7 @@ select (@id := id) - id from t3;
 kill @id;
 drop table t2,t3;
 connection master;
---error 0,1053,2013
+--error 0,1317,2013
 reap;
 connection master1;
 --replace_column 2 # 5 #

sql/records.cc

@@ -56,6 +56,7 @@ void init_read_record_idx(READ_RECORD *info, THD *thd, TABLE *table,
                           bool print_error, uint idx)
 {
   bzero((char*) info,sizeof(*info));
+  info->thd= thd;
   info->table= table;
   info->file=  table->file;
   info->record= table->record[0];
@@ -240,6 +241,12 @@ void end_read_record(READ_RECORD *info)
 
 static int rr_handle_error(READ_RECORD *info, int error)
 {
+  if (info->thd->killed)
+  {
+    info->thd->send_kill_message();
+    return 1;
+  }
+
   if (error == HA_ERR_END_OF_FILE)
     error= -1;
   else
@@ -260,12 +267,7 @@ static int rr_quick(READ_RECORD *info)
   int tmp;
   while ((tmp= info->select->quick->get_next()))
   {
-    if (info->thd->killed)
-    {
-      my_error(ER_SERVER_SHUTDOWN, MYF(0));
-      return 1;
-    }
-    if (tmp != HA_ERR_RECORD_DELETED)
+    if (info->thd->killed || (tmp != HA_ERR_RECORD_DELETED))
     {
       tmp= rr_handle_error(info, tmp);
       break;
@@ -331,16 +333,11 @@ int rr_sequential(READ_RECORD *info)
   int tmp;
   while ((tmp=info->file->rnd_next(info->record)))
   {
-    if (info->thd->killed)
-    {
-      info->thd->send_kill_message();
-      return 1;
-    }
     /*
       rnd_next can return RECORD_DELETED for MyISAM when one thread is
       reading and another deleting without locks.
     */
-    if (tmp != HA_ERR_RECORD_DELETED)
+    if (info->thd->killed || (tmp != HA_ERR_RECORD_DELETED))
     {
       tmp= rr_handle_error(info, tmp);
       break;

sql/sql_class.h

@@ -44,6 +44,8 @@ extern char internal_table_name[2];
 extern char empty_c_string[1];
 extern const char **errmesg;
 
+extern bool volatile shutdown_in_progress;
+
 #define TC_LOG_PAGE_SIZE   8192
 #define TC_LOG_MIN_SIZE    (3*TC_LOG_PAGE_SIZE)
 
@@ -1801,8 +1803,12 @@ class THD :public Statement,
   {
     int err= killed_errno();
     if (err)
+    {
+      if ((err == KILL_CONNECTION) && !shutdown_in_progress)
+        err = KILL_QUERY;
       my_message(err, ER(err), MYF(0));
     }
+  }
   /* return TRUE if we will abort query if we make a warning now */
   inline bool really_abort_on_warning()
   {