The world's most popular open source database
Functionality added or changed:
Incompatible Change:
In MySQL 5.1.6, when log tables were implemented, the default
log destination for the general query and slow query log was
TABLE. This default has been changed to
FILE, which is compatible with MySQL 5.0, but
incompatible with earlier releases of MySQL 5.1 from 5.1.6 to
5.1.20. If you are upgrading from MySQL 5.0 to this release, no
logging option changes should be necessary. However, if you are
upgrading from 5.1.6 through 5.1.20 to this release and were
using TABLE logging, use the
--log-output=TABLE option explicitly to
preserve your server's table-logging behavior.
In MySQL 5.1.x, this bug was addressed twice because it turned out that the default was set in two places, only one of which was fixed the first time. (Bug#29993)
Incompatible Change:
The innodb_log_arch_dir system variable
(which has been deprecated since MySQL 5.0.24) has been removed
and should no longer be used.
Incompatible Change: On Windows only, the mysqld-nt has been removed from this release and all future releases. The mysqld server now includes named-pipe support as standard, and you do not have to use the mysqld-nt version to enable named-pipe support.
Bugs fixed:
Incompatible Change: Several issues were identified for stored programs (stored functions and procedures, triggers, and events) and views containing non-ASCII symbols. These issues involved conversion errors due to incomplete character set information when translating these objects to and from stored format, such as:
Parsing the original object definition so that it can be stored.
Compiling the stored definition into executable form when the object is invoked.
Retrieval of object definitions from
INFORMATION_SCHEMA tables.
Displaying the object definition in SHOW
statements. This issue also affected
mysqldump, which uses
SHOW.
The fix for the problems is to store character set information from the object creation context so that this information is available when the object needs to be used later. The context includes the client character set, the connection character set and collation, and the collation of the database with which the object is associated.
As a result of the patch, several tables have new columns:
In the mysql database, the
proc and event tables
now have these columns:
character_set_client,
collation_connection,
db_collation,
body_utf8.
In INFORMATION_SCHEMA, the
VIEWS table now has these
columns: CHARACTER_SET_CLIENT,
COLLATION_CONNECTION. The
ROUTINES,
TRIGGERS, and
EVENTS tables now have these
columns: CHARACTER_SET_CLIENT,
COLLATION_CONNECTION,
DATABASE_COLLATION.
These columns store the session values of the
character_set_client and
collation_connection system variables, and
the collation of the database with which the object is
associated. The values are those in effect at object creation
time. (The saved database collation is not the value of the
collation_database system variable, which
applies to the default database; the database that contains the
object is not necessarily the default database.)
Several SHOW statements now display
additional columns corresponding to the new table columns. These
statements are: SHOW CREATE
EVENT, SHOW CREATE
FUNCTION, SHOW CREATE
PROCEDURE, SHOW CREATE
VIEW, SHOW EVENTS,
SHOW FUNCTION STATUS,
SHOW PROCEDURE STATUS,
SHOW TRIGGERS.
A new statement, SHOW CREATE
TRIGGER is introduced and is used by
mysqldump for producing
CREATE TRIGGER statements.
Subsequent to the patch just described, it was discovered that the patch broke mysql_upgrade; this has been corrected.
The fixes for the problems just describe affect
all existing stored programs and views.
(For example, you will see warnings about “no creation
context.”) To avoid warnings from the server about the
use of old definitions from any release prior to 5.1.21, you
should dump stored programs and views with
mysqldump after upgrading to 5.1.21, and
then reload them to recreate them with new definitions. Invoke
mysqldump with a
--default-character-set option that names the
non-ASCII character set that was used for the definitions when
the objects were originally defined.
(Bug#25221, Bug#21249, Bug#30027, Bug#16291, Bug#11986, Bug#25212, Bug#19443, Bug#30029)

