fixed up lock counting code - Monty's suggestions

updated manual about table lock counter
fixed coredump in DROP DATABASE with long bogus name by non-root user
fixed bug in handling STOP immediately after ROTATE
added test case for buffer overrun on DROP DATABASE by non-root user
added test case for the STOP bug in replication

Docs/manual.texi

@@ -20285,59 +20285,64 @@ The following columns are returned:
 below, though the format and numbers probably differ:
 
 @example
-+--------------------------+------------+
-| Variable_name            | Value      |
-+--------------------------+------------+
-| Aborted_clients          | 0          |
-| Aborted_connects         | 0          |
-| Bytes_received           | 142160923  |
-| Bytes_sent               | 1161910370 |
-| Connections              | 30022      |
-| Created_tmp_disk_tables  | 0          |
-| Created_tmp_tables       | 8988       |
-| Delayed_insert_threads   | 0          |
-| Delayed_writes           | 0          |
-| Delayed_errors           | 0          |
-| Flush_commands           | 1          |
-| Handler_delete           | 462604     |
-| Handler_read_first       | 95882      |
-| Handler_read_key         | 27681068   |
-| Handler_read_next        | 265008218  |
-| Handler_read_prev        | 3022500    |
-| Handler_read_rnd         | 36900998   |
-| Handler_read_rnd_next    | 252097176  |
-| Handler_update           | 16945404   |
-| Handler_write            | 66826676   |
-| Key_blocks_used          | 14955      |
-| Key_read_requests        | 90131960   |
-| Key_reads                | 163268     |
-| Key_write_requests       | 7573912    |
-| Key_writes               | 3780151    |
-| Max_used_connections     | 0          |
-| Not_flushed_key_blocks   | 0          |
-| Not_flushed_delayed_rows | 0          |
-| Open_tables              | 0          |
-| Open_files               | 0          |
-| Open_streams             | 0          |
-| Opened_tables            | 44598      |
-| Questions                | 1866024    |
-| Select_full_join         | 0          |
-| Select_full_range_join   | 0          |
-| Select_range             | 68187      |
-| Select_range_check       | 0          |
-| Select_scan              | 31440      |
-| Slave_running            | OFF        |
-| Slow_launch_threads      | 0          |
-| Slow_queries             | 0          |
-| Sort_range               | 0          |
-| Sort_rows                | 36650500   |
-| Sort_scan                | 5298       |
-| Threads_cached           | 0          |
-| Threads_connected        | 1          |
-| Threads_created          | 30022      |
-| Threads_running          | 1          |
-| Uptime                   | 39613      |
-+--------------------------+------------+
++--------------------------+--------+
+| Variable_name            | Value  |
++--------------------------+--------+
+| Aborted_clients          | 0      |
+| Aborted_connects         | 0      |
+| Bytes_received           | 629539 |
+| Bytes_sent               | 736394 |
+| Connections              | 62     |
+| Created_tmp_disk_tables  | 0      |
+| Created_tmp_tables       | 0      |
+| Created_tmp_files        | 0      |
+| Delayed_insert_threads   | 0      |
+| Delayed_writes           | 0      |
+| Delayed_errors           | 0      |
+| Flush_commands           | 1      |
+| Handler_delete           | 0      |
+| Handler_read_first       | 1      |
+| Handler_read_key         | 9201   |
+| Handler_read_next        | 0      |
+| Handler_read_prev        | 0      |
+| Handler_read_rnd         | 0      |
+| Handler_read_rnd_next    | 45     |
+| Handler_update           | 5998   |
+| Handler_write            | 0      |
+| Key_blocks_used          | 407    |
+| Key_read_requests        | 27683  |
+| Key_reads                | 407    |
+| Key_write_requests       | 0      |
+| Key_writes               | 0      |
+| Max_used_connections     | 60     |
+| Not_flushed_key_blocks   | 0      |
+| Not_flushed_delayed_rows | 0      |
+| Open_tables              | 60     |
+| Open_files               | 66     |
+| Open_streams             | 0      |
+| Opened_tables            | 66     |
+| Questions                | 9308   |
+| Select_full_join         | 0      |
+| Select_full_range_join   | 0      |
+| Select_range             | 0      |
+| Select_range_check       | 0      |
+| Select_scan              | 0      |
+| Slave_running            | OFF    |
+| Slave_open_temp_tables   | 0      |
+| Slow_launch_threads      | 0      |
+| Slow_queries             | 0      |
+| Sort_merge_passes        | 0      |
+| Sort_range               | 0      |
+| Sort_rows                | 0      |
+| Sort_scan                | 0      |
+| Table_locks_immediate    | 3183   |
+| Table_locks_waited       | 6030   |
+| Threads_cached           | 30     |
+| Threads_created          | 61     |
+| Threads_connected        | 31     |
+| Threads_running          | 31     |
+| Uptime                   | 135    |
++--------------------------+--------+                                          
 @end example
 
 @cindex variables, status
@@ -20400,6 +20405,12 @@ open by the slave thread
 @item @code{Sort_range} @tab Number of sorts that where done with ranges.
 @item @code{Sort_rows}  @tab Number of sorted rows.
 @item @code{Sort_scan}  @tab Number of sorts that where done by scanning the table.
+@item @code{Table_locks_immediate} @tab Number of times a table lock was
+acquired immediately. Available after 3.23.33.
+@item @code{Table_locks_waited} @tab Number of times a table lock could not
+be acquired immediately and a wait was needed. If this is high, and you
+have performance problems, you should first optimize your queries, and then
+either split your table(s) or use replication. Available after 3.23.33.
 @item @code{Threads_cached} @tab Number of threads in the thread cache.
 @item @code{Threads_connected} @tab Number of currently open connections.
 @item @code{Threads_created} @tab Number of threads created to handle connections.
@@ -40814,6 +40825,9 @@ not yet 100 % confident in this code.
 @appendixsubsec Changes in release 3.23.33
 @itemize bullet
 @item
+Added @code{Table_locks_immediate} and @code{Table_locks_waited} status
+variables
+@item
 Fixed bug in replication that broke slave server start with existing
 @code{master.info}. This fixes a bug introduced in 3.23.32.
 @item
@@ -46638,10 +46652,15 @@ for @code{BDB} tables. @xref{Internal locking}.  With @code{MyISAM}
 tables one can freely mix @code{INSERT} and @code{SELECT} without locks
 (@code{Versioning}).
 
+Starting in version 3.23.33, you can analyze the table lock contention
+on your system by checkining @code{Table_locks_waited} and
+@code{Table_locks_immediate} environemt variables.
+
 Some database users claim that @strong{MySQL} cannot support near the
 number of concurrent users because it lacks row-level locking.  This is
 a may be true for some specific applications, but is' not generally
-true. As always this depends totally on what the application does and what is the access/update pattern of the data.
+true. As always this depends totally on what the application does and what
+is the access/update pattern of the data. 
 
 Pros for row locking:
 

include/thr_lock.h

@@ -27,7 +27,8 @@ extern "C" {
 #include <my_list.h>
 
 struct st_thr_lock;
-
+extern ulong locks_immediate,locks_waited ;
+  
 enum thr_lock_type { TL_IGNORE=-1,
 		     TL_UNLOCK,			/* UNLOCK ANY LOCK */
 		     TL_READ,			/* Read lock */

mysql-test/r/rpl000018.result

+Log_name
+master-bin.001
+master-bin.002
+n
+3351

mysql-test/r/status.result

 Variable_name	Value
-Table_locks_immediate	5
+Table_locks_immediate	0
 Table_locks_waited	0
 Variable_name	Value
-Table_locks_immediate	8
+Table_locks_immediate	3
 Table_locks_waited	1

mysql-test/t/overflow.test

+connect (con1,localhost,boo,,test,0,mysql-master.sock);
+connection con1;
+-- error 1064;
+drop database AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA;

mysql-test/t/rpl000018-master.opt

+-O max_binlog_size=4096

mysql-test/t/rpl000018-master.sh

+rm -f $MYSQL_TEST_DIR/var/lib/master-bin.* 
+cp $MYSQL_TEST_DIR/std_data/master-bin.001  $MYSQL_TEST_DIR/var/lib/
+echo ./master-bin.001 >  $MYSQL_TEST_DIR/var/lib/master-bin.index

mysql-test/t/rpl000018-slave.opt

+--skip-slave-start --abort-slave-event-count=1

mysql-test/t/rpl000018.test

+connect (master,localhost,root,,test,0,mysql-master.sock);
+connect (slave,localhost,root,,test,0,mysql-slave.sock);
+connection slave;
+reset slave;
+slave start;
+connection master;
+show master logs;
+drop table if exists t1;
+create table t1(n int);
+insert into t1 values (3351);
+save_master_pos;
+connection slave;
+sync_with_master;
+select * from t1;
+connection master;
+drop table t1;
+save_master_pos;
+connection slave;
+sync_with_master;

mysql-test/t/status.test

 connect (con1,localhost,root,,test,0,mysql-master.sock);
 connect (con2,localhost,root,,test,0,mysql-master.sock);
 
-#don't polute binlog
+flush status;
 show status like 'Table_lock%';
 connection con1;
 SET SQL_LOG_BIN=0;
@@ -20,4 +20,4 @@ unlock tables;
 connection con1;
 reap;
 show status like 'Table_lock%';
-
+drop table t1;

mysys/thr_lock.c

@@ -387,7 +387,7 @@ static my_bool wait_for_lock(struct st_lock_list *wait, THR_LOCK_DATA *data,
   else
   {
     result=0;
-    ++locks_waited;
+    statistic_increment(locks_waited, &THR_LOCK_lock);
     if (data->lock->get_status)
       (*data->lock->get_status)(data->status_param);
     check_locks(data->lock,"got wait_for_lock",0);

sql/mysqld.cc

@@ -260,7 +260,6 @@ ulong query_id=1L,long_query_count,long_query_time,aborted_threads,
       delayed_queue_size,delayed_insert_threads,delayed_insert_writes,
       delayed_rows_in_use,delayed_insert_errors,flush_time, thread_created;
 ulong filesort_rows, filesort_range_count, filesort_scan_count;
-extern "C" ulong locks_immediate, locks_waited;
 ulong filesort_merge_passes;
 ulong select_range_check_count, select_range_count, select_scan_count;
 ulong select_full_range_join_count,select_full_join_count;

sql/slave.cc

@@ -1055,9 +1055,12 @@ static int exec_event(THD* thd, NET* net, MASTER_INFO* mi, int event_len)
       break;
                   
     case STOP_EVENT:
-      close_temporary_tables(thd);
-      mi->inc_pos(event_len);
-      flush_master_info(mi);
+      if(mi->pos > 4) // stop event should be ignored after rotate event
+	{
+          close_temporary_tables(thd);
+          mi->inc_pos(event_len);
+          flush_master_info(mi);
+	}
       delete ev;
       break;
     case ROTATE_EVENT:

sql/sql_base.cc

@@ -32,7 +32,6 @@
 TABLE *unused_tables;				/* Used by mysql_test */
 HASH open_cache;				/* Used by mysql_test */
 
-extern "C" ulong locks_waited, locks_immediate;
 
 static int open_unireg_entry(THD *thd,TABLE *entry,const char *db,
 			     const char *name, const char *alias, bool locked);
@@ -1167,8 +1166,8 @@ bool wait_for_tables(THD *thd)
   {
     /* Now we can open all tables without any interference */
     thd->proc_info="Reopen tables";
-    if(!(result=reopen_tables(thd,0,0)))
-       ++locks_waited;
+    result=reopen_tables(thd,0,0);
+     
   }
   pthread_mutex_unlock(&LOCK_open);
   thd->proc_info=0;

sql/sql_parse.cc

@@ -1886,6 +1886,13 @@ check_access(THD *thd,uint want_access,const char *db, uint *save_priv,
 
   if (db == any_db)
     return FALSE;				// Allow select on anything
+  
+  if (strlen(db) > NAME_LEN || check_db_name(db))
+    {
+      net_printf(&thd->net,ER_WRONG_DB_NAME, db);
+      return TRUE;
+    }
+
   if (db && (!thd->db || strcmp(db,thd->db)))
     db_access=acl_get(thd->host, thd->ip, (char*) &thd->remote.sin_addr,
 		      thd->priv_user, db); /* purecov: inspected */

sql/sql_repl.cc

@@ -392,7 +392,7 @@ sweepstakes if you report the bug";
 	thd->mysys_var->current_mutex = log_lock;
 	thd->mysys_var->current_cond = &COND_binlog_update;
 	const char* proc_info = thd->proc_info;
-	thd->proc_info = "Waiting for update";
+	thd->proc_info = "Slave connection: waiting for binlog update";
 	pthread_mutex_unlock(&thd->mysys_var->mutex);
 
 	bool read_packet = 0, fatal_error = 0;