Dear MySQL users,
MySQL Server 5.6.2 (Milestone Release) is a new version of the world's
most popular open source database.
The new features in these releases are of beta quality. As with any
other pre-production release, caution should be taken when installing on
production level systems or systems with critical data.
Note that 5.6.2 includes all features in MySQL 5.5. For an overview of
what's new in MySQL 5.6, please see the section "What Is New in MySQL
5.6" below, or view it online at
For information on installing MySQL 5.6.2 on new servers, please see the
MySQL installation documentation at
For upgrading from previous MySQL releases, please see the important
upgrade considerations at
Please note that *downgrading* from these releases to a previous release
series is not supported.
MySQL Server 5.6 is available in source and binary form for a number of
platforms from the "Development Releases" selection of our download
Not all mirror sites may be up to date at this point in time, so if you
can't find this version on some mirror, please try again later or choose
another download site.
We welcome and appreciate your feedback, bug reports, bug fixes,
The list of all "Bugs Fixed" for 5.6.2 may also be viewed online at
If you are running a MySQL production level system, we would like to
direct your attention to MySQL Enterprise Edition, which includes the
most comprehensive set of MySQL production, backup, monitoring,
modeling, development, and administration tools so businesses can
achieve the highest levels of MySQL performance, security and uptime.
D.1.2. Changes in MySQL 5.6.2 (11 April 2011)
Explicit Partition Selection
* Partitioning: It is now possible to select one or more
partitions or subpartitions when querying from a partitioned
table. In addition, many data modification statements (DELETE,
INSERT, REPLACE, UPDATE, LOAD DATA, and LOAD XML) that act on
partitioned tables also now support explicit partition
selection. For example, assume we have a table named t with
some integer column named c, and t has 4 partitions named p0,
p1, p2, and p3. Then the query SELECT * FROM t PARTITION (p0,
p1) WHERE c < 5 returns rows only in partitions p0 and p1 that
match the WHERE condition, while partitions p2 and p3 are not
For additional information and examples, see Section 16.5,
"Partition Selection," as well as the descriptions of the
statements just listed.
Row Image Control
* Replication: Added the binlog_row_image server system
variable, which can be used to enable row image control for
row-based replication. This means that you can potentially
save disk space, network resources, and memory usage by the
MySQL Server by logging only those columns that are required
for uniquely identifying rows, or which are actually changed
on each row, as opposed to logging all columns for each and
every row change event. In addition, you can use a "noblob"
mode where all columns, except for unneeded BLOB or TEXT
columns, are logged.
For more information, see Section 220.127.116.11, "System variables
used with the binary log." (Bug #47200, Bug #11755426, Bug
#47303, Bug #56917, Bug #11755426, Bug #11755513, Bug
Crash-Safe Binary Log
* Replication: Support for checksums when writing and reading
the binary log is added to the MySQL Server. Writing checksums
into the binary log is disabled by default; it can be enabled
by starting the server with the --binlog-checksum option. To
cause the server to read checksums from the binary log, start
the server with the --master-verify-checksum option. The
--slave-sql-verify-checksum option causes the slave to read
checksums from the relay log.
* Replication: The MySQL Server now records and reads back only
complete events or transactions to and from the binary log. By
default, the server now logs the length of the event as well
as the event itself and uses this information to verify that
the event was written correctly to the log. A master also uses
by default this value to verify events when reading from the
If you enable writing of checksums (using the binlog_checksum
system variable), the master can use these instead by enabling
the master_verify_checksum system variable. The slave I/O
thread also verifies events received from the master. You can
cause the slave SQL thread to use checksums (if available) as
well, when reading from the relay log, by enabling the
slave_sql_verify_checksum system variable on the slave.
Slave Log Tables
* Replication: It is now possible to write information about the
slave connection to the master and about the slave's execution
point within the relay log to tables rather than files.
Logging of master connection information and of slave relay
log information to tables can be done independently of one
another; this is controlled by the --master-info-repository
and --relay-log-info-repository server options. When
--master-info-repository is set to TABLE, connection
information is logged in the slave_master_info table in the
mysql system database. When --relay-log-info-repository is set
to TABLE, relay log information is logged to the
slave_relay_log_info table, also in the mysql database.
Globally Unique Server IDs
* Replication: Implemented globally unique IDs for MySQL
servers. A UUID is now obtained automatically when the MySQL
server starts. The server first checks for a UUID written in
the auto.cnf file (in the server's data directory), and uses
this UUID if found. Otherwise, the server generates a new UUID
and saves it to this file (and creates the file if it does not
already exist). This UUID is available as the server_uuid
MySQL replication masters and slaves know each other's UUIDs.
The value of a slave's UUID can be read on the master as the
system variable slave_uuid, as well as in the output of SHOW
SLAVE HOSTS. After a slave is started (with START SLAVE), the
value of the master's UUID is available on the slave as the
master_uuid system variable, as well as in the output of SHOW
For more information, see Section 15.1.3, "Replication and
Binary Logging Options and Variables." (Bug #33815, Bug
See also Bug #16927, Bug #11745543.
* The optimizer now more efficiently handles queries (and
subqueries) of the following form:
SELECT ... FROM single_table ... ORDER BY non_index_column
[DESC] LIMIT N;
That type of query is common in web applications that display
only a few rows from a larger result set. For example:
SELECT col1, ... FROM t1 ... ORDER BY name LIMIT 10;
SELECT col1, ... FROM t1 ... ORDER BY RAND() LIMIT 15;
If the sort elements for N rows are small enough to fit in the
sort buffer, which has a size of sort_buffer_size, the server
can avoid using a merge file and perform the sort entirely in
memory. For details, see Section 18.104.22.168, "Optimizing LIMIT
* The optimizer implements Disk-Sweep Multi-Range Read. Reading
rows using a range scan on a secondary index can result in
many random disk accesses to the base table when the table is
large and not stored in the storage engine's cache. With the
Disk-Sweep Multi-Range Read (MRR) optimization, MySQL tries to
reduce the number of random disk access for range scans by
first scanning the index only and collecting the keys for the
relevant rows. Then the keys are sorted and finally the rows
are retrieved from the base table using the order of the
primary key. The motivation for Disk-sweep MRR is to reduce
the number of random disk accesses and instead achieve a more
sequential scan of the base table data. For more information,
see Section 7.13.10, "Multi-Range Read Optimization."
* The optimizer implements Index Condition Pushdown (ICP), an
optimization for the case where MySQL retrieves rows from a
table using an index. Without ICP, the storage engine
traverses the index to locate rows in the base table and
returns them to the MySQL server which evaluates the WHERE
condition for the rows. With ICP enabled, and if parts of the
WHERE condition can be evaluated by using only fields from the
index, the MySQL server pushes this part of the WHERE
condition down to the storage engine. The storage engine then
evaluates the pushed index condition by using the index entry
and only if this is satisfied is base row be read. ICP can
reduce the number of accesses the storage engine has to do
against the base table and the number of accesses the MySQL
server has to do against the storage engine. For more
information, see Section 7.13.4, "Index Condition Pushdown
Performance Schema Notes
* The Performance Schema has these additions:
+ The Performance Schema now has tables that contain
summaries for table and index I/O wait events, as
generated by the wait/io/table/sql/handler instrument:
o table_io_waits_summary_by_table aggregates table I/O
wait events. The grouping is by table.
o table_io_waits_summary_by_index_usage aggregates
table index I/O wait events. The grouping is by
The information in these tables can be used to assess the
impact of table I/O performed by applications. For
example, it is possible to see which tables are used and
which indexes are used (or not used), or to identify
bottlenecks on a table when multiple applications access
it. The results may be useful to change how applications
issue queries against a database, to minimize application
footprint on the server and to improve application
performance and scalability.
A change that accompanies the new tables is that the
events_waits_current table now has an INDEX_NAME column
to identify which index was used for that operation that
generated the event. The same is true of the
event-history tables, events_waits_history, and
+ The Performance Schema now has an instrument named
wait/lock/table/sql/handler in the setup_instruments
table for instrumenting table lock wait events. It
differs from wait/io/table/sql/handler, which instruments
table I/O. This enables independent instrumentation of
table I/O and table locks.
Accompanying the new instrument, the Performance Schema
has a table named table_lock_waits_summary_by_table that
aggregates table lock wait events, as generated by the
new instrument. The grouping is by table.
The information in this table may be used to assess the
impact of table locking performed by applications. The
results may be useful to change how applications issue
queries against the database and use table locks, to
minimize the application footprint on the server and to
improve application performance and scalability. For
example, an application locking tables for a long time
may negatively affect other applications, and the
instrumentation makes this visible.
+ To selectively control which tables are instrumented for
I/O and locking, use the setup_objects table. See Section
22.214.171.124, "Pre-Filtering by Object."
+ The setup_consumers table contents have changed.
Previously, the table used a "flat" structure with a
one-to-one correspondence between consumer name and
destination table. This has been replaced with a
hierarchy of consumer settings that enable progressively
finer control of which destinations receive events. The
previous xxx_summary_xxx consumers no longer exist.
Instead, the Performance Schema maintains appropriate
summaries automatically for the levels are which settings
in the consumer hierarchy are enabled. For example, if
only the top-level (global) consumer is enabled, only
global summaries are maintained. Others, such as
thread-level summaries, are not. See Section 126.96.36.199,
"Pre-Filtering by Consumer." In addition, optimizations
have been added to reduce Performance Schema overhead.
+ It is now possible to filter events by object using the
new setup_objects table. Currently, this table can be
used to selectively instrument tables, based on schema
names and/or table names. See Section 188.8.131.52,
"Pre-Filtering by Object." A new table,
objects_summary_global_by_type, summarizes events for
+ It is now possible to filter events by thread, and the
Performance Schema collects more information for each
thread. A new table, setup_actors, can be used to
selectively instrument user connections, based on the
user name and/or host name of each connecting session.
The threads table, which contains a row for each active
server thread, was extended with several new columns.
With these additions, the information available in
threads is like that available from the
INFORMATION_SCHEMA.PROCESSLIST table or the output from
SHOW PROCESSLIST. Thus, all three serve to provide
information for thread-monitoring purposes. Use of
threads differs from use of the other two thread
information sources in these ways:
o Access to threads does not require a mutex and has
minimal impact on server performance.
INFORMATION_SCHEMA.PROCESSLIST and SHOW PROCESSLIST
have negative performance consequences because they
require a mutex.
o threads provides additional information for each
thread, such as whether it is a foreground or
background thread, and the location within the
server associated with the thread.
o threads provides information about background
threads. This means that threads can be used to
monitor activity the other thread information
o You can control which threads are monitored by
setting the INSTRUMENTED column or by using the
For these reasons, DBAs who perform server monitoring
using INFORMATION_SCHEMA.PROCESSLIST or SHOW PROCESSLIST
may wish to monitor using threads instead.
If you upgrade to this release of MySQL from an earlier
version, you must run mysql_upgrade (and restart the server)
to incorporate these changes into the performance_schema
For more information, see Chapter 19, "MySQL Performance
Functionality added or changed:
* Incompatible Change: The following obsolete constructs have
been removed. Where alternatives are shown, applications
should be updated to use them.
+ The FLUSH MASTER and FLUSH SLAVE statements. Use the
RESET MASTER and RESET SLAVE statements instead.
+ The --log server option and the log system variable.
Instead, use the --general_log option to enable the
general query log and the --general_log_file=file_name
option to set the general query log file name.
+ The --log-slow-queries server option and the
log_slow_queries system variable. Instead, use the
--slow_query_log option to enable the slow query log and
the --slow_query_log_file=file_name option to set the
slow query log file name.
+ The --one-thread server option. Use
+ The --skip-thread-priority server option.
+ The engine_condition_pushdown system variable. Use the
engine_condition_pushdown flag of the optimizer_switch
+ The have_csv, have_innodb, have_ndbcluster
have_partitioning system variables. Use SHOW ENGINES
+ The sql_big_tables system variable. Use big_tables
+ The sql_low_priority_updates system variable. Use
+ The sql_max_join_size system variable. Use max_join_size
+ The SLAVE START and SLAVE STOP statements. Use the START
SLAVE and STOP SLAVE statements instead.
+ The ONE_SHOT modifier for the SET statement.
* Important Change: Replication: Replication filtering options
such as --replicate-do-db, --replicate-rewrite-db, and
--replicate-do-table were not consistent with one another in
regard to case sensitivity. Now all --replicate-* options
follow the same rules for case sensitivity applying to names
of databases and tables elsewhere in the MySQL server,
including the effects of the lower_case_table_names system
variable. (Bug #51639, Bug #11759334)
* Important Change: Replication: Added the MASTER_RETRY_COUNT
option to the CHANGE MASTER TO statement, and a corresponding
Master_Retry_Count column to the output of SHOW SLAVE STATUS.
The option sets the value shown in this column.
MASTER_RETRY_COUNT is intended eventually to replace the older
--master-retry-count server option, and is now the preferred
method for setting the maximum number of times that the slave
may attempt to reconnect after losing its connection to the
master. (Bug #44209, Bug #11752887, Bug #44486, Bug #11753110)
* Important Change: Replication: Added the
--binlog-rows-query-log-events option for mysqld. Using this
option causes a server logging in row-based mode to write
informational rows query log events (SQL statements, for
debugging and other purposes) to the binary log. MySQL server
and MySQL programs from MySQL 5.6.2 and later normally ignore
such events, so that they do not pose an issue when reading
the binary log. mysqld and mysqlbinlog from previous MySQL
releases cannot read such events in the binary log, and fail
if they attempt to do so. For this reason, you should never
prepare logs for a MySQL 5.6.1 or earlier replication slave
server (or other reader such as mysqlbinlog) with this option
enabled on the master. (Bug #11758695, Bug #50935, Bug
* Replication: SHOW SLAVE STATUS now displays the actual number
of retries for each connection attempt made by the I/O thread.
(Bug #56416, Bug #11763675)
* Replication: Added the Slave_last_heartbeat status variable,
which shows when a replication slave last received a heartbeat
signal. The value is displayed using TIMESTAMP format. (Bug
* Replication: Timestamps have been added to the output of SHOW
SLAVE STATUS to show when the most recent I/O and SQL thread
errors occurred. The Last_IO_Error column is now prefixed with
the timestamp for the most recent I/O error, and
Last_SQL_Error shows the timestamp for the most recent SQL
thread error. The timestamp values use the format YYMMDD
HH:MM:SS in both of these columns. For more information, see
Section 184.108.40.206, "SHOW SLAVE STATUS Syntax." (Bug #43535,
* Replication: On MySQL replication slaves having multiple
network interfaces, it is now possible to set which interface
to use for connecting to the master using the
MASTER_BIND='interface' option in a CHANGE MASTER TO
The value set by this option can be seen in the Master_Bind
column of the output from SHOW SLAVE STATUS or the Bind column
of the mysql.slave_master_info table. (Bug #25939, Bug
* Replication: Added the log_bin_basename system variable, which
contains the complete filename and path to the binary log
file. (The log_bin system variable shows only whether or not
binary logging is enabled; log_bin_basename, however, reflects
the name set with the --log-bin server option.) Also added
relay_log_basename system variable, which shows the filename
and complete path to the relay log file.
See also Bug #19614, Bug #11745759.
* Changes to replication in MySQL 5.6 make mysqlbinlog output
generated by the --base64-output=ALWAYS option unusable.
ALWAYS is now an invalid value for this option. If the option
is given without a value, the effect is now the same as
--base64-output=AUTO rather than --base64-output=ALWAYS.
See also Bug #28760, Bug #11746794.
* Replication: The SHOW SLAVE STATUS statement now has a
Master_Info_File field indicating the location of the
master.info file. (Bug #50316, Bug #11758151)
* Replication: MySQL now supports delayed replication such that
a slave server deliberately lags behind the master by at least
a specified amount of time. The default delay is 0 seconds.
Use the new MASTER_DELAY option for CHANGE MASTER TO to set
the delay to N seconds:
CHANGE MASTER TO MASTER_DELAY = N;
An event received from the master is not executed until at
least N seconds later than its execution on the master.
START SLAVE and STOP SLAVE take effect immediately and ignore
any delay. RESET SLAVE resets the delay to 0.
SHOW SLAVE STATUS has three new fields that provide
information about the delay:
+ SQL_Delay: The number of seconds that the slave must lag
+ SQL_Remaining_Delay: When Slave_SQL_Running_State is
Waiting until MASTER_DELAY seconds after master executed
event, this field contains the number of seconds left of
the delay. At other times, this field is NULL.
+ Slave_SQL_Running_State: The state of the SQL thread
(analogous to Slave_IO_State). The value is identical to
the State value of the SQL thread as displayed by SHOW
When the slave SQL thread is waiting for the delay to elapse
before executing an event, SHOW PROCESSLIST displays its State
value as Waiting until MASTER_DELAY seconds after master
The relay-log.info file now contains the delay value, so the
file format has changed. See Section 220.127.116.11, "Slave Status
Logs." In particular, the first line of the file now indicates
how many lines are in the file. If you downgrade a slave
server to a version older than MySQL 5.6, the older server
will not read the file correctly. To address this, modify the
file in a text editor to delete the initial line containing
the number of lines.
The introduction of delayed replication entails these
+ Previously the BINLOG statement could execute all types
of events. Now it can execute only format description
events and row events.
+ The output from mysqlbinlog --base64-output=ALWAYS cannot
be parsed. ALWAYS becomes an invalid value for this
option in 5.6.1.
For additional information, see Section 15.3.9, "Delayed
Replication." (Bug #28760, Bug #11746794)
* The Performance Schema now includes instrumentation for table
input and output. Instrumented operations include row-level
accesses to persistent base tables or temporary tables.
Operations that affect rows are fetch, insert, update, and
delete. For a view, waits are associated with base tables
referenced by the view.
InnoDB Configurable Data Dictionary cache
* InnoDB Storage Engine: InnoDB now uses the table_cache option
value as a guide to remove table metadata from memory when
many different InnoDB tables are accessed. InnoDB table
metadata is removed using a variation of the LRU algorithm.
(Parent and child tables in foreign key relationships are
exempted from removal.) (Bug #20877, Bug #11745884)
INFORMATION_SCHEMA Table for InnoDB Metrics
* InnoDB Storage Engine: A new INFORMATION_SCHEMA table,
INNODB_METRICS, lets you query low-level InnoDB performance
information, getting cumulative counts, averages, and min/max
values for internal aspects of the storage engine operation.
You can start, stop, and reset the metrics counters using the
configuration variables innodb_monitor_enable,
innodb_monitor_disable, innodb_monitor_reset, and
INFORMATION_SCHEMA Tables for InnoDB Buffer Pool Information
* InnoDB Storage Engine: The new INFORMATION_SCHEMA tables
INNODB_BUFFER_PAGE, INNODB_BUFFER_PAGE_LRU, and
INNODB_BUFFER_POOL_STATS display InnoDB buffer pool
information for tuning on large-memory or highly loaded
INFORMATION_SCHEMA Tables for InnoDB Data Dictionary
* InnoDB Storage Engine: The InnoDB data dictionary, containing
metadata about InnoDB tables, columns, indexes, and foreign
keys, is available for SQL queries through a set of
Persistent InnoDB Optimizer Statistics
* InnoDB Storage Engine: The optimizer statistics for InnoDB
tables can now persist across server restarts, producing more
stable query performance. You can also control the amount of
sampling done to estimate cardinality for each index,
resulting in more accurate optimizer statistics.
* InnoDB Storage Engine: InnoDB can optionally log details about
all deadlocks that occur, to assist with troubleshooting and
diagnosis. This feature is controlled by the
innodb_print_all_deadlocks configuration option. (Bug #1784,
, Bug #11744783, Bug #17572)
* InnoDB Storage Engine: A separate InnoDB thread (page_cleaner)
now handles the flushing of dirty pages that was formerly done
by the InnoDB master thread.
* InnoDB Storage Engine: The configuration option
innodb_purge_threads can now be set to a value higher than 1.
* InnoDB Storage Engine: The InnoDB kernel mutex has been split
into several mutexes and rw-locks, for improved concurrency.
* Windows provides APIs based on UTF-16LE for reading from and
writing to the console. MySQL now supports a utf16le character
set for UTF-16LE, so the mysql client for Windows has been
modified to provide improved Unicode support by using these
To take advantage of this change, you must run mysql within a
console that uses a compatible Unicode font and set the
default character set to a Unicode character set that is
supported for communication with the server. For instructions,
see Section 18.104.22.168.1, "Unicode Support on Windows."
* Several changes were made to optimizer-related system
+ The optimizer_switch system variable has new
engine_condition_pushdown and index_condition_pushdown
flags to control whether storage engine condition
pushdown and index condition pushdown optimizations are
used. The engine_condition_pushdown system variable now
is deprecated. For information about condition pushdown,
see Section 7.13.3, "Engine Condition Pushdown
Optimization," and Section 7.13.4, "Index Condition
+ The optimizer_switch system variable has new mrr and
mrr_cost_based flags to control use of the Multi-Range
Read optimization. The optimizer_use_mrr system variable
has been removed. For information about Multi-Range Read,
see Section 7.13.10, "Multi-Range Read Optimization."
+ The join_cache_level system variable has been renamed to
optimizer_join_cache_level. This enables SHOW VARIABLES
LIKE 'optimizer%' to show more optimizer-related
* In MySQL 5.5, setting optimizer_search_depth to the deprecated
value of 63 switched to the algorithm used in MySQL 5.0.0 (and
previous versions) for performing searches. The value of 63 is
now treated as invalid.
* The Unicode implementation has been extended to a utf16le
character set, which corresponds to the UTF-16LE encoding of
the Unicode character set. This is similar to utf16 (UTF16)
but is little-endian rather than big-endian.
utf16le has two collations available:
+ utf16le_general_ci: The default collation, case sensitive
(similar to utf16_general_ci.
+ utf16le_bin: Case sensitive, with by-codepoint comparison
that provides the same order as utf16_bin.
There are some limitations on the use of utf16le. With the
exception of the item regarding user-defined collations, these
are the same as the limitations on ucs2, utf16, and utf32.
+ utf16le cannot be used as a client character set, which
means that it also does not work for SET NAMES or SET
+ It is not possible to use LOAD DATA INFILE to load data
files that use utf16le.
+ FULLTEXT indexes cannot be created on a column that uses
utf16le. However, you can perform IN BOOLEAN MODE
searches on the column without an index.
+ The use of ENCRYPT() with utf16le is not recommended
because the underlying system call expects a string
terminated by a zero byte.
+ It is not possible to create user-defined UCA collations
for utf16le because there is no utf16le_unicode_ci
collation, which would serve as the basis for such
* Unicode collation names now may include a version number to
indicate the Unicode Collation Algorithm (UCA) version on
which the collation is based. Initial collations thus created
use version UCA 5.2.0. For example, utf8_unicode_520_ci is
based on UCA 5.2.0. UCA-based Unicode collation names that do
not include a version number are based on version 4.0.0.
LOWER() and UPPER() perform case folding according to the
collation of their argument. A character that has uppercase
and lowercase versions only in a Unicode version more recent
than 4.0.0 will be converted by these functions only if the
argument has a collation that uses a recent enough UCA
The LDML rules for creating user-defined collations are
extended to permit an optional version attribute in
<collation> tags to indicate the UCA version on which the
collation is based. If the version attribute is omitted, its
default value is 4.0.0. See Section 9.4.4, "Adding a UCA
Collation to a Unicode Character Set."
* Croatian collations were added for Unicode character sets:
utf8_croatian_ci, ucs2_croatian_ci, utf8mb4_croatian_ci,
utf16_croatian_ci, and utf32_croatian_ci. Thee collations have
tailoring for Croatian letters: ÄŒ, Ä†, DÅ¾,
Ä They are based on Unicode 4.0.
* Vietnamese collations were added for the Unicode character
sets. Those based on Unicode Collation Algorithm 5.2.0 have
names of the form xxx_vietnamese_520_ci (for example,
utf8_vietnamese_520_ci). Those based on Unicode Collation
Algorithm 4.0.0 have names of the form xxx_vietnamese_ci (for
example, utf8_vietnamese_ci). These collations are the same as
the corresponding xxx_unicode_520_ci and xxx_unicode_ci
collations except for precomposed characters which are
accented versions of "A", "D", "E", "O", and "U". There is no
change to ideographic characters derived from Chinese. There
are no digraphs.
* The Unicode character sets now have a xxx_german2_ci collation
that provides DIN-2 (phone book) ordering (for example,
utf8_german2_ci). See Section 22.214.171.124, "Unicode Character
* The Romansh locale 'rm_CH' is now a permissible value for the
lc_time_names system variable. (Bug #50915, Bug #11758678)
* Partitioning: It is now possible to exchange a partition of a
partitioned table or a subpartition of a subpartitioned table
with a nonpartitioned table that otherwise has the same
structure using the ALTER TABLE ... EXCHANGE PARTITION
statement. This can be used, for example, for importing and
For more information and examples, see Section 16.3.3,
"Exchanging Partitions and Subpartitions with Tables."
* The mysql_upgrade, mysqlbinlog, mysqlcheck, mysqlimport,
mysqlshow, and mysqlslap clients now have --default-auth and
--plugin-dir options for specifying which authentication
plugin and plugin directory to use. (Bug #58139, Bug #11765201)
* mysqlbinlog now has a --binlog-row-event-max-size option to
enable large row events to be read from binary log files. (Bug
* mysqlbinlog now has the capability to back up a binary log in
its original binary format. When invoked with the
--read-from-remote-server and --raw options, mysqlbinlog
connects to a server, requests the log files, and writes
output files in the same format as the originals. See Section
126.96.36.199, "Using mysqlbinlog to Back Up Binary Log Files."
* mysqldump now has an --add-drop-trigger option which adds a
DROP TRIGGER IF EXISTS statement before each dumped trigger
definition. (Bug #34325, Bug #11747863)
* mysqldump --xml now displays comments from column definitions.
(Bug #13618, Bug #11745324)
* A new SQL function, WEIGHT_STRING(), returns the weight string
for an input string. The weight string represents the sorting
and comparison value of the input string.
* MySQL distributions now include auth_socket, a server-side
authentication plugin that authenticates clients that connect
from the local host through the Unix socket file. The plugin
uses the SO_PEERCRED socket option to obtain information about
the user running the client program (and thus can be built
only on systems that support this option. For a connection to
succeed, the plugin requires a match between the login name of
the connecting client user and the MySQL user name presented
by the client program. For more information, see Section
188.8.131.52.4, "The Socket Peer-Credential Authentication Plugin."
(Bug #59017, Bug #11765993)
* Boolean system variables can be enabled at run time by setting
them to the value ON or OFF, but previously this did not work
at server startup. Now at startup such variables can be
enabled by setting them to ON or TRUE, or disabled by setting
them to OFF or FALSE. Any other nonnumeric variable is
invalid. (Bug #46393, Bug #11755200)
See also Bug #11754743, Bug #51631.
* Previously, for queries that were aborted due to a sort
problem, the server wrote the message Sort aborted to the
error log. Now the server writes more information to provide a
more specific message, such as:
Sort aborted: Out of memory (Needed 24 bytes)
Out of sort memory, consider increasing server sort buffer size
Sort aborted: Out of sort memory, consider increasing
server sort buffer size
Sort aborted: Incorrect number of arguments for FUNCTION
test.f1; expected 0, got 1
In addition, if the server was started with --log-warnings=2,
the server write information about the host, user, and query.
(Bug #36022, Bug #11748358)
* Previously, for queries that were aborted due to a sort
problem or terminated with KILL in the middle of a sort, the
server wrote the message Sort aborted to the error log. Now
the server writes more information about the cause of the
error. These causes include:
Insufficient disk space in tmpdir prevented tmpfile from
Insufficient memory for sort_buffer_size to be allocated
Somebody ran KILL id in the middle of a filesort
The server was shutdown while some queries were sorting
A transaction got rolled back or aborted due to lock wait
timeout or deadlock
Unexpected errors, such as source table or even tmp table was
corrupt processing of a subquery failed which was also sorting
(Bug #30771, Bug #11747102)
* The undocumented SHOW NEW MASTER statement has been removed.
* MySQL distributions now include mysql_clear_password, a
client-side authentication plugin that sends the password to
the server without hashing or encryption. Although this is
insecure, and thus appropriate precautions should be taken
(such as using an SSL connection), the plugin is useful in
conjunction with server-side plugins that must have access to
the original password in clear text. For more information, see
Section 184.108.40.206.3, "The Clear Text Client-Side Authentication
* A new plugin service, my_plugin_log_service, enables plugins
to report errors and specify error messages. The server writes
the messages to the error log. See Section 21.2.6, "MySQL
Services for Plugins."
* There is now a bind_address system variable containing the
value of the --bind-address option. This enables the address
to be accessed at runtime. (Bug #44355, Bug #11752999)
* "Unknown table" error messages that included only the table
name now include the database name as well. (Bug #34750, Bug
* Previously, EXPLAIN output for a large union truncated the
UNION RESULT row at the end of the list as follows if the
string became too large:
To make it easier to understand the union boundaries,
truncation now occurs in the middle of the string:
(Bug #30597, Bug #11747073)
* The OpenGIS specification defines functions that test the
relationship between two geometry values. MySQL originally
implemented these functions such that they used object
bounding rectangles and returned the same result as the
corresponding MBR-based functions. Corresponding versions are
now available that use precise object shapes. These versions
are named with an ST_ prefix. For example, Contains() uses
object bounding rectangles, whereas ST_Contains() uses object
shapes. For more information, see Section 220.127.116.11.2,
"Functions That Test Spatial Relationships Between
There are also now ST_ aliases for existing spatial functions
that were already exact. For example, ST_IsEmpty() is an alias
for IsEmpty() (Bug #4249, Bug #11744883)
* TO_BASE64() and FROM_BASE64() functions are now available to
perform encoding to and from base-64 strings.
* The Block Nested-Loop (BNL) Join algorithm previously used
only for inner joins has been extended and can be employed for
outer join operations, including nested outer joins. For more
information, see Section 7.13.11, "Block Nested-Loop Joins."
In conjunction with this work, there is a new system variable,
optimizer_join_cache_level, that controls how join buffering
* A --bind-address option has been added to a number of MySQL
client programs: mysql, mysqldump, mysqladmin, mysqlbinlog,
mysqlcheck, mysqlimport, and mysqlshow. This is for use on a
computer having multiple network interfaces, and enables you
to choose which interface is used to connect to the MySQL
The list of bugs fixed will follow in a separate mail, because
of size restrictions on the mailing lists.
MySQL/ORACLE Release Engineering Team
|• MySQL Community Server 5.6.2 has been released||Hery Ramilison||11 Apr|