Functionality added or changed:
Plugin API: Incompatible Change: MySQL 5.1 adds support for a very flexible plugin API that enables loading and unloading of various components at runtime, without restarting the server. Although the work on this is not finished yet, plugin full-text parsers are a first step in this direction. This allows users to implement their own input filter on the indexed text, enabling full-text search capability on arbitrary data such as PDF files or other document formats. A pre-parser full-text plugin performs the actual parsing and extraction of the text and hands it over to the built-in MySQL full-text search. (Author: Sergey Vojtovich)
The plugin API requires the mysql.plugin
table. When upgrading from an older version of MySQL, you should
run the mysql_fix_privilege_tables command to
create this table. See
Section 4.4.4, “mysql_fix_privilege_tables — Upgrade MySQL System Tables”.
Plugins are installed in the directory named by the
plugin_dir
system variable.
This variable also controls the location from which the server
loads user-defined functions (UDFs), which is a change from
earlier versions of MySQL. That is, all UDF library files now
must be installed in the plugin directory. When upgrading from
an older version of MySQL, you must migrate your UDF files to
the plugin directory.
Incompatible Change:
Renamed the table_cache
system
variable to table_open_cache
.
Any scripts that refer to
table_cache
should be updated
to use the new name.
MySQL Cluster:
VARCHAR
columns used in MySQL
Cluster tables are now variable-sized; that is, they now only
allocate as much space as required to store the data.
Previously, a
VARCHAR(
column
allocated n+2 bytes (aligned to 4 bytes), regardless of whether
the actual inserted value required that much space. (In other
words, a n
)VARCHAR
column always
required the same, fixed, amount of storage as a
CHAR
column of the same size.)
Partitioning: allows distributing portions of individual tables across a file system, according to rules which can be set when the table is created. In effect, different portions of a table are stored as separate tables in different locations, but from the user point of view, the partitioned table is still a single table. See Chapter 18, Partitioning, for further information on this functionality. (Author: Mikael Ronström)
RAND()
no longer allows
nonconstant initializers. (Prior to MySQL 5.1.3, the effect of
nonconstant initializers is undefined.)
(Bug#6172)
Added the
table_definition_cache
system
variable. If you use a large number of tables, you can create a
large table definition cache to speed up opening of tables. The
table definition cache takes less space and does not use file
descriptors, unlike the normal table cache.
SET
sets an option to the specified value and writes it
to the config file See Section 4.6.10, “mysqlmanager — The MySQL Instance Manager”, for
more details on these new commands. (Author: Petr Chardin)
instance_name
.
option_name
=option_value
SHOW
provides a listing of all log files used by the
instance. (Author: Petr Chardin)
instance_name
LOG
FILES
Added the SHOW AUTHORS
statement.
Fast ALTER TABLE
: Operations that
change only table metadata and not table data do not require a
temporary table to be used, which improves performance. For
example, renaming a column changes only the
.frm
file and no longer uses a temporary
table.
The Instance Manager (IM) now has some additional functionality:
SHOW
provides a listing of all log files used by
the instance. (Author: Petr Chardin)
instance_name
LOG
FILES
SHOW
retrieves a part of the specified log file.
(Author: Petr Chardin)
instance_name
LOG
{ERROR | SLOW | GENERAL} size
SET
sets an option to the specified value and writes
it to the config file See
Section 4.6.10, “mysqlmanager — The MySQL Instance Manager”, for more details on
these new commands. (Author: Petr Chardin)
instance_name
.
option_name
=option_value
SHOW
retrieves a part of the specified log file. (Author:
Petr Chardin)
instance_name
LOG
{ERROR | SLOW | GENERAL} size
Added the SHOW FUNCTION CODE
and
SHOW PROCEDURE CODE
statements
(available only for servers that have been built with debugging
support). See Section 12.4.5.29, “SHOW PROCEDURE CODE
Syntax”.
The performance of boolean full-text searches (using the “+” Operator) has been improved. See Section 11.8, “Full-Text Search Functions”, for more details about full-text searching. (Author: Sergey Vojtovich)
Bugs fixed:
RESET MASTER
failed to delete log
files on Windows. One consequence of this change is that server
opens the general query and slow log files in shared mode, so
now they can be renamed while the server has them open
(something not true in previous versions).
(Bug#13377)
Set functions could not be aggregated in outer subqueries. (Bug#12762)
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