This is a milestone release, for use at your own risk. Significant development changes take place in milestone releases and you may encounter compatibility issues, such as data format changes that require attention in addition to the usual procedure of running mysql_upgrade. For example, you may find it necessary to dump your data with mysqldump before the upgrade and reload it afterward.
INNODB_METRICS, lets you query
InnoDB performance information,
getting cumulative counts, averages, and minimum/maximum values
for internal aspects of the storage engine operation. You can
start, stop, and reset the metrics counters using the
InnoDB data dictionary, containing
InnoDB tables, columns,
indexes, and foreign keys, is available for SQL queries through
a set of
The optimizer statistics for
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. This feature involves the
innodb_analyze_is_persistent (later replaced
ANALYZE TABLE statement.
See Configuring Persistent Optimizer Statistics Parameters for details.
To ease the memory load on systems with huge numbers of tables,
InnoDB now frees up the memory associated
with an opened table using an LRU algorithm to select tables
that have gone the longest without being accessed. To reserve
more memory to hold metadata for open
tables, increase the value of the
InnoDB treats this
value as a “soft limit” for the number of open
table instances in the
InnoDB data dictionary
cache. The actual number of tables with cached metadata could be
higher than the value specified for
InnoDB system tables, and parent
and child tables in foreign key relationships, is never evicted
from memory. For additional information, refer to the
(Bug #20877, Bug #11745884)
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 Multi-Range Read Optimization.
The optimizer now more efficiently handles queries (and subqueries) of the following form:
SELECT ... FROM
single_table... ORDER BY
non_index_column[DESC] LIMIT [
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;
The sort buffer has a size of
sort_buffer_size. If the sort
N rows are small enough
to fit in the sort buffer
M was specified), the server can
avoid using a merge file and perform the sort entirely in
memory. For details, see Optimizing LIMIT Queries.
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
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
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
Index Condition Pushdown Optimization.
It is now possible to select one or more partitions or
subpartitions when querying a partitioned table. In addition,
many data modification statements
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
t has 4 partitions
p3. Then the query
SELECT * FROM t
PARTITION (p0, p1) WHERE c < 5 returns rows only in
WHERE condition, whereas partitions
p3 are not checked.
For additional information and examples, see Partition Selection, as well as the descriptions of the statements just listed.
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
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 the operation that generated the event. The
same is true of the event-history tables,
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
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
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; the instrumentation makes this visible.
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
For more information, see MySQL Performance Schema.
MySQL distributions now include
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 The Socket Peer-Credential Authentication Plugin.
(Bug #59017, Bug #11765993, Bug #9411, Bug #11745104)
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
The Cleartext Client-Side Authentication Plugin.
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 binary log.
If you enable writing of checksums (using the
variable), the master can use these instead by enabling the
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
system variable on the slave.
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
option. To cause the server to read checksums from the binary
log, start the server with the
option causes the slave to read checksums from the relay log.
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
server options. When
--master-info-repository is set
TABLE, connection information is logged in
slave_master_info table in the
mysql system database. When
TABLE, relay log information is logged
slave_relay_log_info table, also in
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
TEXT columns, are logged.
For more information, see System Variables Used with Binary Logging. (Bug #47200, Bug #47303, Bug #56917, Bug #11755426, Bug #11755513, Bug #11764116)
page_cleaner) now handles the flushing of
dirty pages that was formerly done by the
InnoDB master thread.
(Bug #11762412, Bug #55004)
variable can now be set to a value higher than 1.
Incompatible Change: The following obsolete constructs have been removed. Where alternatives are shown, applications should be updated to use them.
Important Change; Replication:
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 #50935, Bug #11758695)
InnoDB can optionally log details about all
deadlocks that occur, to assist with troubleshooting and
diagnosis. This feature is controlled by the
(Bug #1784, Bug #17572)
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
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
(Bug #25939, Bug #11746389)
system variable, which contains the complete file name and path
to the binary log file. (The
log_bin system variable shows
only whether or not binary logging is enabled;
reflects the name set with the
--log-bin server option.) Also
variable, which shows the file name and complete path to the
relay log file.
References: See also Bug #19614, Bug #11745759.
and mysqlslap clients now have
--plugin-dir options for specifying which
authentication plugin and plugin directory to use.
The server now includes the thread ID in rows written to the
slow query log. In the slow query log file, the thread ID is the
last value in the line. In the
log table, there is a new
To update the
slow_log table if you are
upgrading from an earlier release, run
mysql_upgrade and restart the server. See
mysql_upgrade — Check and Upgrade MySQL Tables.
(Bug #53630, Bug #11761166)
The server now writes thread shutdown messages to the error log during the shutdown procedure. (Bug #48388, Bug #11756464)
--init-file option is
given, the server now writes messages indicating the beginning
and end of file execution to the error log.
(Bug #48387, Bug #11756463)
Boolean system variables can be enabled at run time by setting
them to the value
OFF, but previously this did not work at
server startup. Now at startup such variables can be enabled by
setting them to
TRUE, or disabled by setting them to
FALSE. Any other
nonnumeric value is invalid.
References: See also Bug #11754743, Bug #51631.
MySQL distributions now include an
file that contains information about the source distribution,
such as the MySQL version from which it was created. MySQL
binary distributions additionally include an
INFO_BIN file that contains information
about how the distribution was built, such as compiler options
and feature flags. In RPM packages, these files are located in
tar.gz and derived packages,
they are located in the
under the location where the distribution is unpacked.
(Bug #42969, Bug #11751935)
Multi-read range access is now based on cost estimates and no longer used for simple queries for which it is not beneficial. (Bug #37576, Bug #11748865)
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
writes 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
aborted to the error log. Now the server writes more
information about the cause of the error. These causes include:
Insufficient disk space in the temporary file directory prevented a temp file from being created
Insufficient memory for
sort_buffer_size to be
in the middle of a
The server was shut down while some queries were sorting
A transaction was rolled back or aborted due to a lock wait timeout or deadlock
Unexpected errors, such as a source table or even temp table was corrupt
Processing of a subquery failed which was also sorting
(Bug #30771, Bug #11747102)
mysqldump --xml now displays comments from column definitions. (Bug #13618, Bug #11745324)
SHOW NEW MASTER statement
has been removed.
A new plugin service,
enables plugins to report errors and specify error messages. The
server writes the messages to the error log. See
MySQL Services for Plugins.
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, and the
mysql client for Windows has been modified to
provide improved Unicode support by using these APIs.
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 Unicode Support on Windows.
LIKE predicates during view
preparation could cause a server crash.
(Bug #54568, Bug #11762026, CVE-2010-3836)
UPDATE statement for an
InnoDB table could be slower than
necessary if it changed a column covered by a prefix index, but
did not change the prefix portion of the value. The fix improves
performance for InnoDB 1.1 in MySQL 5.5 and higher, and the
InnoDB Plugin for MySQL 5.1.
(Bug #58912, Bug #11765900)
Incompatible Change; Replication:
It is no longer possible to issue a
TABLE ... SELECT statement which changes any tables
other than the table being created. Any such statement is not
executed and instead fails with an error.
This means that, prior to upgrading from a previous release, you
should rewrite any
TABLE ... SELECT statements that cause changes in
other tables so that the statements no longer do so.
This change also has implications for statement-based
replication between a MySQL 5.6 (or later slave) and a master
running a previous version of MySQL. In such a case, if a
TABLE ... SELECT statement on the master that causes
changes in other tables succeeds on the master, the statement
nonetheless fails on the slave, causing replication to stop. To
keep this from happening, you should either use row-based
replication, or rewrite the offending statement before running
it on the master.
(Bug #11749792, Bug #11745361, Bug #39804, Bug #55876)
References: See also Bug #47899.
auto_increment_increment is greater than
one, values generated by a bulk insert that reaches the maximum
column value could wrap around rather producing an overflow
As a consequence of the fix, it is no longer possible for an
auto-generated value to be equal to the maximum
UNSIGNED value. It is still possible to store that
value manually, if the column can accept it.
(Bug #39828, Bug #11749800)
Important Change; Partitioning:
Date and time functions used as partitioning functions now have
the types of their operands checked; use of a value of the wrong
type is now disallowed in such cases. In addition,
col_name is a
DATETIME column, is now
disallowed altogether because its return value depends on the
value of the
(Bug #54483, Bug #11761948)
References: See also Bug #57071, Bug #11764255.
Important Change; Replication:
CHANGE MASTER TO statement
required the value for
RELAY_LOG_FILE to be
an absolute path, whereas the
path could be relative.
The inconsistent behavior is resolved by permitting relative
RELAY_LOG_FILE, in which case the
path is assumed to be relative to the slave's data
(Bug #12190, Bug #11745232)
The partitioning handler did not pass locking information to a
table's storage engine handler. This caused high contention
and thus slower performance when working with partitioned
This fix introduces a new configuration option,
which defines the size of the
change buffer as a
percentage of the size of the
buffer pool. Because the
change buffer shares memory space with the buffer pool, a
workload with a high rate of DML operations could cause pages
accessed by queries to age out of the buffer pool sooner than
desirable. This fix also devotes more I/O capacity to flushing
entries from the change buffer when it exceeds 1/2 of its
(Bug #11766168, Bug #59214)
The presence of a double quotation mark inside the
COMMENT field for a column could prevent a
foreign key constraint from being created properly.
(Bug #59197, Bug #11766154)
InnoDB returned values for
“rows examined” in the query plan that were higher
NULL values were treated in an
inconsistent way. The inaccurate statistics could trigger
“false positives” in combination with the
max_join_size setting, because
the queries did not really examine as many rows as reported.
A new configuration option
innodb_stats_method lets you specify how
NULL values are treated when calculating
index statistics. Allowed values are
nulls_equal (the default),
null_ignored. The meanings of these values
are similar to those of the
... PARTITION statements could cause memory leaks.
(Bug #56380, Bug #11763641)
References: See also Bug #46949, Bug #11755209, Bug #56996, Bug #11764187.
When using the statement-based logging format,
DUPLICATE KEY UPDATE and
statements affecting transactional tables that did not fail were
not written to the binary log if they did not insert any rows.
(With statement-based logging, all successful statements should
be logged, whether they do or do not cause any rows to be
(Bug #59338, Bug #11766266)
STOP SLAVE stopped the
slave I/O thread first and then stopped the slave SQL thread;
thus, it was possible for the I/O thread to stop after
replicating only part of a transaction which the SQL thread was
executing, in which case—if the transaction could not be
rolled back safely—the SQL thread could hang.
STOP SLAVE stops the slave
SQL thread first and then stops the I/O thread; this guarantees
that the I/O thread can fetch any remaining events in the
transaction that the SQL thread is executing, so that the SQL
thread can finish the transaction if it cannot be rolled back
(Bug #58546, Bug #11765563)
USE statements to its output only
when the default database changed between events. To illustrate
how this could cause problems, suppose that a user issued the
following sequence of statements:
CREATE DATABASE mydb; USE mydb; CREATE TABLE mytable (
column_definitions); DROP DATABASE mydb; CREATE DATABASE mydb; USE mydb; CREATE TABLE mytable (
When played back using mysqlbinlog, the
CREATE TABLE statement
failed with Error: No Database Selected
because the second
was not played back, due to the fact that a database other than
mydb was never selected.
This fix ensures that mysqlbinlog outputs a
USE statement whenever it reads
one from the binary log.
(Bug #50914, Bug #11758677)
--help text for
mysqlbinlog now indicates that the
-v) option outputs pseudo-SQL that is not
necessarily valid SQL and cannot be guaranteed to work verbatim
in MySQL clients.
(Bug #47557, Bug #11755743)
Two unused test files in
storage/ndb/test/sql contained incorrect
versions of the GNU Lesser General Public License. The files and
the directory containing them have been removed.
References: See also Bug #11810156.
Queries that used
cp1251 strings could result in an
“illegal mix of collations” error.
(Bug #60101, Bug #11766874)
An assertion was raised if an
XA COMMIT was
issued when an XA transaction had already encountered an error
(such as a deadlock) that required the transaction to be rolled
(Bug #59986, Bug #11766788)
On some systems, debug builds of
could fail due to an uninitialized variable.
(Bug #59906, Bug #11766729)
system variable to an invalid value caused a server crash.
(Bug #59894, Bug #11766719)
Attempting to create a spatial index on a
CHAR column longer than 31 bytes
led to an assertion failure if the server was compiled with
(Bug #59888, Bug #11766714)
Aggregation followed by a subquery could produce an incorrect result. (Bug #59839, Bug #11766675)
The Performance Schema did not update status handler status
STATUS LIKE '%handler%' produced undercounted values.
(Bug #59799, Bug #11766645)
Internally, XOR items partially behaved like functions and partially as conditions. This resulted in inconsistent handling and crashes. The issue is fixed by consistently treating XOR items as functions. (Bug #59793, Bug #11766642)
An incorrect character set pointer passed to
my_strtoll10_mb2() caused an assertion to be
(Bug #59648, Bug #11766519)
The server and client did not always properly negotiate authentication plugin names. (Bug #59453, Bug #11766356)
FIND_IN_SET() could work
differently in MySQL 5.5 than in 5.1.
(Bug #59405, Bug #11766317)
mysqldump did not quote database names in
ALTER DATABASE statements in its
output, which could cause an error at reload time for database
names containing a dash.
(Bug #59398, Bug #11766310)
filesort fell back to an ordinary
sort/merge, it could fail to handle memory correctly.
(Bug #59331, Bug #11766260)
Comparisons of aggregate values with
TIMESTAMP values were incorrect.
(Bug #59330, Bug #11766259)
The “greedy” query plan optimizer failed to consider the size of intermediate query results when calculating the cost of a query. This could result in slowly executing queries when there are much faster execution plans available. (Bug #59326, Bug #11766256)
A query of the following form returned an incorrect result,
where the values for
col_name in the
result set were entirely replaced with
col_name... ORDER BY
(Bug #59308, Bug #11766241)
MYSQL_HOME environment variable was being
(Bug #59280, Bug #11766219)
SHOW PROFILE could truncate
source file names or fail to show function names.
(Bug #59273, Bug #11766214)
DIV expressions, assignment of
the result to multiple variables could cause a server crash.
(Bug #59241, Bug #11766191)
References: See also Bug #8457.
could return an incorrect result in some cases.
(Bug #59211, Bug #11766165)
With index condition pushdown enabled, a join could produce an extra row due to parts of the select condition for the second table in the join not being evaluated. (Bug #59186, Bug #11766144)
ESCAPE clause for the
LIKE operator permits only
expressions that evaluate to a constant at execution time, but
aggregate functions were not being rejected.
(Bug #59149, Bug #11766110)
Valgrind warnings about uninitialized variables were corrected. (Bug #59145, Bug #11766106)
Memory leaks detected by Valgrind, some of which could cause incorrect query results, were corrected. (Bug #59110, Bug #11766075)
mysqlslap failed to check for a
NULL return from
mysql_store_result() and crashed
trying to process the result set.
(Bug #59109, Bug #11766074)
There was an erroneous restriction on file attributes for
INFILE. The requirement that a file be located in the
database directory or world readable is now that the be located
in the database directory or readable by the user account used
to run the server.
(Bug #59085, Bug #11766052)
SHOW CREATE TRIGGER failed if
there was a temporary table with the same name as the trigger
(Bug #58996, Bug #11765972)
In a subquery, a
UNION with no
referenced tables (or only a reference to the
DUAL virtual table) did not permit an
ORDER BY clause.
(Bug #58970, Bug #11765950)
max_allowed_packet was set larger than
16MB, the server failed to reject too-large packets with
“Packet too large” errors.
(Bug #58887, Bug #11765878)
With index condition pushdown enabled, incorrect results were
returned for queries on
LIMIT, when the column in the
WHERE condition contained
(Bug #58838, Bug #11765835)
An uninitialized variable for the index condition pushdown access method could result in a server crash or Valgrind warnings. (Bug #58837, Bug #11765834)
NOT IN predicate with a subquery containing
HAVING clause could retrieve too many rows,
when the subquery itself returned
(Bug #58818, Bug #11765815)
Running a query against an
table twice, first with index condition pushdown enabled and
then with it disabled, could produce different results.
(Bug #58816, Bug #11765813)
An assertion was raised if a stored routine had a
statement that failed but due to the
had not reported any error.
(Bug #58709, Bug #11765717)
WHERE conditions of the following forms were
evaluated incorrectly and could return incorrect results:
null-valued-const-expressionNOT IN (
subquery) IS UNKNOWN
(Bug #58628, Bug #11765642)
EXPLAIN EXTENDED for a
query that would use condition pushdown could cause
mysqld to crash.
(Bug #58553, Bug #11765570)
OUTER JOIN query using
return an incorrect result.
(Bug #58490, Bug #11765513)
col_name IS NULL
Starting the server with the
option, where the file name had no extension, caused a server
(Bug #58455, Bug #11765482)
Outer joins with an empty table could produce incorrect results. (Bug #58422, Bug #11765451)
In debug builds,
FORMAT(...)) could cause a server crash.
(Bug #58371, Bug #11765406)
Some string-manipulating SQL functions use a shared string
object intended to contain an immutable empty string. This
object was used by the SQL function
SUBSTRING_INDEX() to return an
empty string when one argument was of the wrong data type. If
the string object was then modified by the SQL function
INSERT(), undefined behavior
(Bug #58165, Bug #11765225)
Condition pushdown optimization could push down conditions with incorrect column references. (Bug #58134, Bug #11765196)
injector::transaction did not have support
(Bug #58082, Bug #11765150)
Parsing nested regular expressions could lead to recursion resulting in a stack overflow crash. (Bug #58026, Bug #11765099)
The fix for Bug #25192 caused
to add an argument separator to distinguish options loaded from
option files from those provided on the command line, whether or
not the application needed it.
(Bug #57953, Bug #11765041)
References: See also Bug #11746296.
The mysql client went into an infinite loop if the standard input was a directory. (Bug #57450, Bug #11764598)
If a multiple-table update updated a row through two aliases and the first update physically moved the row, the second update failed to locate the row. This resulted in different errors depending on the storage engine, although these errors did not accurately describe the problem:
MyISAM, which is
nontransactional, the update executed first was performed but
the second was not. In addition, for two equal multiple-table
update statements, one could succeed and the other fail
depending on whether the record actually moved, which is
Now such an update returns an error if it will update a table through multiple aliases, and perform an update that may physically move the row in at least one of these aliases. (Bug #57373, Bug #11764529, Bug #55385, Bug #11762751)
Outer joins on a unique key could return incorrect results. (Bug #57034, Bug #11764219)
For a query that used a subquery that included
BY inside a
< ANY() construct,
no rows were returned when there should have been.
(Bug #56690, Bug #11763918)
Some RPM installation scripts used a hardcoded value for the data directory, which could result in a failed installation for users who have a nonstandard data directory location. The same was true for other configuration values such as the PID file name. (Bug #56581, Bug #11763817)
On FreeBSD and OpenBSD, the server incorrectly checked the range of the system date, causing legal values to be rejected. (Bug #55755, Bug #11763089)
On Windows, an object in thread local storage could be used before the object was created. (Bug #55730, Bug #11763065)
If one connection locked the
WITH READ LOCK or
mysql.func WRITE and a second connection tried to
either create or drop a UDF function, a deadlock occurred when
the first connection tried to use a UDF function.
(Bug #53322, Bug #11760878)
DISTINCT aggregates on
UNSIGNED fields could trigger an assertion.
(Bug #52171, Bug #11759827)
On FreeBSD, if mysqld was killed with a
SIGHUP signal, it could corrupt
(Bug #51023, Bug #11758773)
An assertion could be raised if −1 was inserted into an
AUTO_INCREMENT column by a statement writing
more than one row.
(Bug #50619, Bug #11758417)
A query that contained an aggregate function but no
GROUP BY clause was implicitly grouped. But
implicitly grouped queries return zero or one row, so ordering
does not make sense.
The parser failed to initialize some internal objects properly, which could cause a server crash in the cleanup phase after statement execution. (Bug #47511, Bug #11755703)
CASE ... WHEN arguments had different
character sets, 8-bit values could be referenced as
raising an assertion.
(Bug #44793, Bug #11753363)
UpdateXML(), if the XML to be
read contained an incomplete XML comment, MySQL read beyond the
end of the XML string when processing, leading to a crash of the
(Bug #44332, Bug #11752979)
Bitmap functions used in one thread could change bitmaps used by other threads, raising an assertion. (Bug #43152, Bug #11752069)
DATE_SUB() return a string if the
first argument is a string, but incorrectly returned a binary
string. Now they return a character string with a collation of
(Bug #31384, Bug #11747221)