Commit 45833dcc authored by unknown's avatar unknown
Browse files

Merge acurtis@bk-internal.mysql.com:/home/bk/mysql-5.1-engines 

into  xiphis.org:/home/antony/work2/p2-bug20168.2


sql/sql_db.cc:
  Auto merged
storage/myisam/mi_check.c:
  Auto merged
storage/myisam/myisamdef.h:
  Auto merged
mysql-test/r/lock_multi.result:
  manual merge
mysql-test/t/lock_multi.test:
  manual merge
parents 01e8913e 25917d6b

mysql-test/r/lock_multi.result

+8 −0
Original line number Diff line number Diff line
@@ -66,3 +66,11 @@ Select_priv 
N

use test;

use test;

CREATE DATABASE mysqltest_1;

FLUSH TABLES WITH READ LOCK;

 DROP DATABASE mysqltest_1;

DROP DATABASE mysqltest_1;

ERROR HY000: Can't execute the query because you have a conflicting read lock

UNLOCK TABLES;

DROP DATABASE mysqltest_1;

ERROR HY000: Can't drop database 'mysqltest_1'; database doesn't exist

mysql-test/t/lock_multi.test

+33 −0
Original line number Diff line number Diff line
@@ -158,3 +158,36 @@ use test; 
connection default;



# End of 5.0 tests

# Bug#19815 - CREATE/RENAME/DROP DATABASE can deadlock on a global read lock

#

connect (con1,localhost,root,,);

connect (con2,localhost,root,,);

#

connection con1;

CREATE DATABASE mysqltest_1;

FLUSH TABLES WITH READ LOCK;

#

# With bug in place: acquire LOCK_mysql_create_table and

# wait in wait_if_global_read_lock().

connection con2;

send DROP DATABASE mysqltest_1;

--sleep 1

#

# With bug in place: try to acquire LOCK_mysql_create_table...

# When fixed: Reject dropping db because of the read lock.

connection con1;

--error ER_CANT_UPDATE_WITH_READLOCK

DROP DATABASE mysqltest_1;

UNLOCK TABLES;

#

connection con2;

reap;

#

connection default;

disconnect con1;

disconnect con2;

# This must have been dropped by connection 2 already,

# which waited until the global read lock was released.

--error ER_DB_DROP_EXISTS

DROP DATABASE mysqltest_1;

sql/sql_db.cc

+46 −14
Original line number Diff line number Diff line
@@ -539,15 +539,26 @@ bool mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info, 
    DBUG_RETURN(-1);

  }



  VOID(pthread_mutex_lock(&LOCK_mysql_create_db));



  /* do not create database if another thread is holding read lock */

  /*

    Do not create database if another thread is holding read lock.

    Wait for global read lock before acquiring LOCK_mysql_create_db.

    After wait_if_global_read_lock() we have protection against another

    global read lock. If we would acquire LOCK_mysql_create_db first,

    another thread could step in and get the global read lock before we

    reach wait_if_global_read_lock(). If this thread tries the same as we

    (admin a db), it would then go and wait on LOCK_mysql_create_db...

    Furthermore wait_if_global_read_lock() checks if the current thread

    has the global read lock and refuses the operation with

    ER_CANT_UPDATE_WITH_READLOCK if applicable.

  */

  if (wait_if_global_read_lock(thd, 0, 1))

  {

    error= -1;

    goto exit2;

  }



  VOID(pthread_mutex_lock(&LOCK_mysql_create_db));



  /* Check directory */

  path_len= build_table_filename(path, sizeof(path), db, "", "");

  path[path_len-1]= 0;                    // Remove last '/' from path
@@ -655,9 +666,9 @@ bool mysql_create_db(THD *thd, char *db, HA_CREATE_INFO *create_info, 
  }



exit:

  VOID(pthread_mutex_unlock(&LOCK_mysql_create_db));

  start_waiting_global_read_lock(thd);

exit2:

  VOID(pthread_mutex_unlock(&LOCK_mysql_create_db));

  DBUG_RETURN(error);

}
@@ -671,12 +682,23 @@ bool mysql_alter_db(THD *thd, const char *db, HA_CREATE_INFO *create_info) 
  int error= 0;

  DBUG_ENTER("mysql_alter_db");



  VOID(pthread_mutex_lock(&LOCK_mysql_create_db));



  /* do not alter database if another thread is holding read lock */

  /*

    Do not alter database if another thread is holding read lock.

    Wait for global read lock before acquiring LOCK_mysql_create_db.

    After wait_if_global_read_lock() we have protection against another

    global read lock. If we would acquire LOCK_mysql_create_db first,

    another thread could step in and get the global read lock before we

    reach wait_if_global_read_lock(). If this thread tries the same as we

    (admin a db), it would then go and wait on LOCK_mysql_create_db...

    Furthermore wait_if_global_read_lock() checks if the current thread

    has the global read lock and refuses the operation with

    ER_CANT_UPDATE_WITH_READLOCK if applicable.

  */

  if ((error=wait_if_global_read_lock(thd,0,1)))

    goto exit2;



  VOID(pthread_mutex_lock(&LOCK_mysql_create_db));



  /* 

     Recreate db options file: /dbpath/.db.opt

     We pass MY_DB_OPT_FILE as "extension" to avoid
@@ -721,9 +743,9 @@ bool mysql_alter_db(THD *thd, const char *db, HA_CREATE_INFO *create_info) 
  send_ok(thd, result);



exit:

  VOID(pthread_mutex_unlock(&LOCK_mysql_create_db));

  start_waiting_global_read_lock(thd);

exit2:

  VOID(pthread_mutex_unlock(&LOCK_mysql_create_db));

  DBUG_RETURN(error);

}
@@ -755,15 +777,26 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent) 
  TABLE_LIST* dropped_tables= 0;

  DBUG_ENTER("mysql_rm_db");



  VOID(pthread_mutex_lock(&LOCK_mysql_create_db));



  /* do not drop database if another thread is holding read lock */

  /*

    Do not drop database if another thread is holding read lock.

    Wait for global read lock before acquiring LOCK_mysql_create_db.

    After wait_if_global_read_lock() we have protection against another

    global read lock. If we would acquire LOCK_mysql_create_db first,

    another thread could step in and get the global read lock before we

    reach wait_if_global_read_lock(). If this thread tries the same as we

    (admin a db), it would then go and wait on LOCK_mysql_create_db...

    Furthermore wait_if_global_read_lock() checks if the current thread

    has the global read lock and refuses the operation with

    ER_CANT_UPDATE_WITH_READLOCK if applicable.

  */

  if (wait_if_global_read_lock(thd, 0, 1))

  {

    error= -1;

    goto exit2;

  }



  VOID(pthread_mutex_lock(&LOCK_mysql_create_db));



  length= build_table_filename(path, sizeof(path), db, "", "");

  strmov(path+length, MY_DB_OPT_FILE);		// Append db option file name

  del_dbopt(path);				// Remove dboption hash entry
@@ -872,7 +905,6 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent) 
exit:

  (void)sp_drop_db_routines(thd, db); /* QQ Ignore errors for now  */

  error= Events::drop_schema_events(thd, db);

  start_waiting_global_read_lock(thd);

  /*

    If this database was the client's selected database, we silently change the

    client's selected database to nothing (to have an empty SELECT DATABASE()
@@ -901,9 +933,9 @@ bool mysql_rm_db(THD *thd,char *db,bool if_exists, bool silent) 
    thd->db= 0;

    thd->db_length= 0;

  }

exit2:

  VOID(pthread_mutex_unlock(&LOCK_mysql_create_db));



  start_waiting_global_read_lock(thd);

exit2:

  DBUG_RETURN(error);

}

storage/myisam/mi_check.c

+16 −18
Original line number Diff line number Diff line
@@ -453,25 +453,24 @@ int chk_key(MI_CHECK *param, register MI_INFO *info) 
    if ((uint) share->base.auto_key -1 == key)

    {

      /* Check that auto_increment key is bigger than max key value */

      ulonglong save_auto_value=info->s->state.auto_increment;

      info->s->state.auto_increment=0;

      ulonglong auto_increment;

      info->lastinx=key;

      _mi_read_key_record(info, 0L, info->rec_buff);

      update_auto_increment(info, info->rec_buff);

      if (info->s->state.auto_increment > save_auto_value)

      auto_increment= retrieve_auto_increment(info, info->rec_buff);

      if (auto_increment > info->s->state.auto_increment)

      {

	mi_check_print_warning(param,

			       "Auto-increment value: %s is smaller than max used value: %s",

			       llstr(save_auto_value,buff2),

			       llstr(info->s->state.auto_increment, buff));

        mi_check_print_warning(param, "Auto-increment value: %s is smaller "

                               "than max used value: %s",

                               llstr(info->s->state.auto_increment,buff2),

                               llstr(auto_increment, buff));

      }

      if (param->testflag & T_AUTO_INC)

      {

        set_if_bigger(info->s->state.auto_increment,

                      auto_increment);

        set_if_bigger(info->s->state.auto_increment,

                      param->auto_increment_value);

      }

      else

	info->s->state.auto_increment=save_auto_value;



      /* Check that there isn't a row with auto_increment = 0 in the table */

      mi_extra(info,HA_EXTRA_KEYREAD,0);
@@ -481,8 +480,8 @@ int chk_key(MI_CHECK *param, register MI_INFO *info) 
      {

	/* Don't count this as a real warning, as myisamchk can't correct it */

	uint save=param->warning_printed;

	mi_check_print_warning(param,

			       "Found row where the auto_increment column has the value 0");

        mi_check_print_warning(param, "Found row where the auto_increment "

                               "column has the value 0");

	param->warning_printed=save;

      }

      mi_extra(info,HA_EXTRA_NO_KEYREAD,0);
@@ -4124,11 +4123,10 @@ void update_auto_increment_key(MI_CHECK *param, MI_INFO *info, 
  }

  else

  {

    ulonglong auto_increment= (repair_only ? info->s->state.auto_increment :

			       param->auto_increment_value);

    info->s->state.auto_increment=0;

    update_auto_increment(info, record);

    ulonglong auto_increment= retrieve_auto_increment(info, record);

    set_if_bigger(info->s->state.auto_increment,auto_increment);

    if (!repair_only)

      set_if_bigger(info->s->state.auto_increment, param->auto_increment_value);

  }

  mi_extra(info,HA_EXTRA_NO_KEYREAD,0);

  my_free((char*) record, MYF(0));

storage/myisam/mi_key.c

+6 −8
Original line number Diff line number Diff line
@@ -509,20 +509,19 @@ int _mi_read_key_record(MI_INFO *info, my_off_t filepos, byte *buf) 




/*

  Update auto_increment info

  Retrieve auto_increment info



  SYNOPSIS

    update_auto_increment()

    retrieve_auto_increment()

    info			MyISAM handler

    record			Row to update



  IMPLEMENTATION

    Only replace the auto_increment value if it is higher than the previous

    one. For signed columns we don't update the auto increment value if it's

    For signed columns we don't retrieve the auto increment value if it's

    less than zero.

*/



void update_auto_increment(MI_INFO *info,const byte *record)

ulonglong retrieve_auto_increment(MI_INFO *info,const byte *record)

{

  ulonglong value= 0;			/* Store unsigned values here */

  longlong s_value= 0;			/* Store signed values here */
@@ -587,6 +586,5 @@ void update_auto_increment(MI_INFO *info,const byte *record) 
    and if s_value == 0 then value will contain either s_value or the

    correct value.

  */

  set_if_bigger(info->s->state.auto_increment,

                (s_value > 0) ? (ulonglong) s_value : value);

  return (s_value > 0) ? (ulonglong) s_value : value;

}