MySQL 5.6 Release Notes
A known limitation of this release:
If you have InnoDB
tables with full-text
search indexes and you are upgrading from MySQL 5.6.10 to a
MySQL version up to and including MySQL 5.6.18, the server
will fail to start after the upgrade (Bug#72079). This bug is
fixed in MySQL 5.6.19. As a workaround, remove full-text
search indexes prior to upgrading and rebuild full-text search
indexes after the upgrade is completed.
It was not possible to upgrade a community RPM to a commercial RPM using rpm -uvh or yum localupdate. To deal with this, the RPM spec file has been updated in MySQL 5.6.11, which has the following consequences:
For a non-upgrade installation (no existing MySQL version installed), it possible to install MySQL using yum.
For upgrades, it is necessary to clean up any earlier MySQL installations. In effect, the update is performed by removing the old installations and installing the new one.
Additional details follow.
For a non-upgrade installation of MySQL 5.6.11, it is possible to install using yum:
shell> yum install MySQL-server-NEWVERSION
.glibc23.i386.rpm
For upgrades to MySQL 5.6.11, the upgrade is performed by removing the old installation and installing the new one. To do this, use the following procedure:
Remove the existing 5.6.X
installation. OLDVERSION
is the
version to remove.
shell> rpm -e MySQL-server-OLDVERSION
.glibc23.i386.rpm
Repeat this step for all installed MySQL RPMs.
Install the new version.
NEWVERSION
is the version to
install.
shell> rpm -ivh MySQL-server-NEWVERSION
.glibc23.i386.rpm
Alternatively, the removal and installation can be done using yum:
shell>yum remove MySQL-server-
shell>OLDVERSION
.glibc23.i386.rpmyum install MySQL-server-
NEWVERSION
.glibc23.i386.rpm
(Bug #16445097, Bug #16445125, Bug #16587285)
Replication:
The functions GTID_SUBTRACT()
and
GTID_SUBSET()
were formerly
available in libmysqld
only when it was built
with replication support. Now these functions are always
available when using this library, regardless of how it was
built.
MySQL no longer uses the default OpenSSL compression. (Bug #16235681)
There is now a distinct error code
(ER_MUST_CHANGE_PASSWORD_LOGIN
)
for the error sent by the server to a client authenticating with
an expired password.
(Bug #16102943)
mysql_config_editor now supports
--port
and --socket
options
for specifying TCP/IP port number and Unix socket file name.
(Bug #15851247)
mysqlcheck has a new
--skip-database
option. The
option value is the name of a database (case sensitive) for
which checks should be skipped.
mysql_upgrade adds this option to
mysqlcheck commands that it generates to
upgrade the system tables in the mysql
database before tables in other databases: It upgrades the
mysql
database, then all databases except the
mysql
database. This avoids problems that can
occur if user tables are upgraded before the system tables.
(Bug #14697538, Bug #68163, Bug #16216384)
The only supported value for the
innodb_mirrored_log_groups
system variable is 1, so this variable is now deprecated.
Setting it to 1 at startup results in a warning. Setting it to a
value other than 1 at startup results in an error and the server
exits. This variable will be removed in a future release.
Incompatible Change; Partitioning:
Changes in the KEY
partitioning hashing
functions used with numeric, date and time,
ENUM
, and
SET
columns in MySQL 5.5 makes
tables using partitioning or subpartitioning by
KEY
on any of the affected column types and
created on a MySQL 5.5 or later server incompatible with a MySQL
5.1 server. This is because the partition IDs as calculated by a
MySQL 5.5 or later server almost certainly differ from those
calculated by a MySQL 5.1 server for the same table definition
and data as a result of the changes in these functions.
The principal changes in the KEY
partitioning
implementation in MySQL 5.5 resulting in this issue were as
follows: 1. The hash function used for numeric and date and time
columns changed from binary to character-based. 2. The base used
for hashing of ENUM
and
SET
columns changed from latin1
ci
characters to binary.
The fix involves adding the capability in MySQL 5.5 and later to
choose which type of hashing to use for KEY
partitioning, which is implemented with a new
ALGORITHM
extension to the PARTITION
BY KEY
option for CREATE
TABLE
and ALTER TABLE
.
Specifying PARTITION BY KEY ALGORITHM=1
([
causes the
server to use the hashing functions as implemented in MySQL 5.1;
using columns
])ALGORITHM=2
causes the server to use
the hashing functions from MySQL 5.5 and later.
ALGORITHM=2
is the default. Using the
appropriate value for ALGORITHM
, you can
perform any of the following tasks:
Create KEY
partitioned tables in MySQL
5.5 and later that are compatible with MySQL 5.1, using
CREATE TABLE ... PARTITION BY KEY ALGORITHM=1
(...)
.
Downgrade KEY
partitioned tables that
were created in MySQL 5.5 or later to become compatible with
MySQL 5.1, using ALTER TABLE ... PARTITION BY KEY
ALGORITHM=1 (...)
.
Upgrade KEY
partitioned tables originally
created in MySQL 5.1 to use hashing as in MySQL 5.5 and
later, using ALTER TABLE ... PARTITION BY KEY
ALGORITHM=2 (...)
.
Important: After such tables are
upgraded, they cannot be used any longer with MySQL 5.1
unless they are first downgraded again using ALTER
TABLE ... PARTITION BY KEY ALGORITHM=1 (...)
on a
MySQL server supporting this option.
This syntax is not backward compatible, and causes errors in
older versions of the MySQL server. When generating
CREATE TABLE ...
PARTITION BY KEY
statements,
mysqldump brackets any occurrence of
ALGORITHM=1
or ALGORITHM=2
in conditional comments such that it is ignored by a MySQL
server whose version is not at least 5.5.31. An additional
consideration for upgrades is that MySQL 5.6 servers prior to
MySQL 5.6.11 do not ignore the ALGORITHM
option in such statements when generated by a MySQL 5.5 server,
due to the that the conditional comments refer to version
5.5.31; in this case, you must edit the dump manually and remove
or comment out the option wherever it occurs before attempting
to load it into a MySQL 5.6.10 or earlier MySQL 5.6 server. This
is not an issue for dumps generated by MySQL 5.6.11 or later
version of mysqldump, where the version used
in such comments is 5.6.11. For more information, see
ALTER TABLE Partition Operations.
As part of this fix, a spurious assertion by
InnoDB
that a deleted row had
previously been read, causing the server to assert on delete of
a row that the row was in the wrong partition, was also removed.
(Bug #14521864, Bug #66462, Bug #16093958, Bug #16274455)
References: See also: Bug #11759782.
Incompatible Change: For debug builds, creating an InnoDB table in strict SQL mode that violated the maximum key length limit caused the server to exit.
A behavior change in consequence of this bug fix: In strict SQL mode, a key length limit violation now results in a error (and the table is not created), rather than a warning and truncation of the key to the maximum key length. This applies to all storage engines. (Bug #16035659)
Important Change; Replication
This fix was reverted in MySQL 5.6.12. See Section 41, “Changes in MySQL 5.6.12 (2013-06-03, General Availability)”.
Executing a statement that performs an implicit commit but whose
changes are not logged when
gtid_next
is set to any value
other than AUTOMATIC
is not permitted. Now in
such cases, the statement fails with an error. This includes the
statements in the following list:
(Bug #16062608)
References: See also: Bug #16484323.
Important Change; Replication:
The version number reported by mysqlbinlog
--version
has been increased
to 3.4.
(Bug #15894381, Bug #67643)
Important Note; Replication: Using row-based logging to replicate from a table to a same-named view led to a failure on the slave. Now, when using row-based logging, the target object type is checked prior to performing any DML, and an error is given if the target on the slave is not actually a table.
It remains possible to replicate from a table to a same-named view using statement-based logging.
(Bug #11752707, Bug #43975)
Performance; InnoDB:
Switching the MySQL table used by the
InnoDB memcached
interface (using the @@
notation), was
made more efficient, by reading cached information about the
cache policy to use for each table. This optimization lets you
frequently switch between tables during a session that uses the
memcached interface, without incurring I/O overhead from
examining table metadata each time.
(Bug #16206654)
Performance; InnoDB: Performance was improved for operations on tables with many rows that were deleted but not yet purged. The speedup applies mainly to workloads that perform bulk deletes, or updates to the primary key columns, and where the system is busy enough to experience purge lag. (Bug #16138582, Bug #68069)
Performance; InnoDB:
The DROP TABLE
statement for a
table using compression
could be slower than necessary, causing a stall for several
seconds. MySQL was unnecessarily decompressing
pages in the
buffer pool related to
the table as part of the DROP
operation.
(Bug #16067973)
Performance; InnoDB: The I/O routines used when the AIO subsystem were made more efficient, to merge consecutive I/O requests into a single operation. This fix solves a performance issue introduced during the 5.6 development cycle. (Bug #16043841, Bug #67973)
InnoDB:
When ADD PRIMARY KEY
columns are reordered in
an ALTER TABLE
statement (for
example: ALTER TABLE t1 ADD PRIMARY KEY(a,b), CHANGE a
a INT AFTER b
), the log apply for
UPDATE
operations failed to find rows.
(Bug #16586355)
InnoDB:
ALTER TABLE
operations on
InnoDB
tables that added a PRIMARY
KEY
using a column prefix could produce an incorrect
result.
(Bug #16544336)
InnoDB:
For ALTER TABLE
operations on
InnoDB
tables that required a table-copying
operation, other transactions on the table might fail during the
copy. However, if such a transaction issued a partial rollback,
the rollback was treated as a full rollback.
(Bug #16544143)
InnoDB:
When parsing a delimited search string such as
“abc-def” in a full-text search,
InnoDB
now uses the same word delimiters as
MyISAM
.
(Bug #16419661)
InnoDB:
Naming inconsistencies were addressed for InnoDB
PERFORMANCE_SCHEMA
key declarations.
(Bug #16414044)
InnoDB:
Status values in the
innodb_ft_config
table would not
update. The innodb_ft_config
is
intended for internal configuration and should not be used for
statistical information purposes. To avoid confusion, column
values that are intended for internal use have been removed from
the innodb_ft_config
table. This
fix also removes the
innodb_ft_config
table and other
internal full text search-related tables that were
unintentionally exposed.
(Bug #16409494, Bug #68502)
InnoDB:
Crash recovery failed with a
!recv_no_log_write
assertion when reading a
page.
(Bug #16405422)
InnoDB: This fix disables a condition for extra splitting of clustered index leaf pages, on compressed tables. Extra page splitting was only done to reserve space for future updates, so that future page splits could be avoided. (Bug #16401801)
InnoDB:
For InnoDB
tables, if a PRIMARY
KEY
on a VARCHAR
column
(or prefix) was empty, index page compression could fail.
(Bug #16400920)
InnoDB:
The InnoDB
page-splitting algorithm could
recurse excessively.
(Bug #16345265)
InnoDB:
Improper testing of compatibility between the referencing and
referenced during
ALTER TABLE ... ADD
FOREIGN
key could cause a server exit.
(Bug #16330036)
InnoDB: Importing a tablespace with the configuration file present would not import the data file. This problem would occur when all pages are not flushed from the buffer pool after a table is altered using the copy and rename approach. This fix ensures that all pages are flushed from the buffer pool when a table is altered using the copy and rename approach. (Bug #16318052)
InnoDB: Rollback did not include changes made to temporary tables by read-only transactions. (Bug #16310467)
InnoDB:
When using ALTER TABLE
to set an
AUTO_INCREMENT
column value to a
user-specified value, InnoDB would set the
AUTO_INCREMENT
value to the user-specified
value even when the AUTO_INCREMENT
value is
greater than the user-specified value. This fix ensures that the
AUTO_INCREMENT
value is set to the maximum of
the user-specified value and MAX(auto_increment_column)+1, which
is the expected behaviour.
(Bug #16310273)
InnoDB:
RENAME TABLE
would result in a
hang due to a MySQL mutex acquisition deadlock.
(Bug #16305265)
InnoDB:
For debug builds, InnoDB
status exporting was
subject to a race condition that could cause a server exit.
(Bug #16292043)
InnoDB:
With innodb_api_enable_mdl=OFF
,
an ALTER TABLE
operation on an
InnoDB
table that required a table copy could
cause a server exit.
(Bug #16287411)
InnoDB:
An assertion failure would occur in heap->magic_n ==
MEM_BLOCK_MAGIC_N
due to a race condition that
appeared when
row_merge_read_clustered_index()
returned an
error.
(Bug #16275237)
InnoDB:
InnoDB now aborts execution on Windows by calling the
abort()
function directly, as it does on
other platforms.
(Bug #16263506)
InnoDB: This fix removes an unnecessary debug assertion related to page_hash locks which only affects debug builds. The debug assertion is no longer valid and should have been removed when hash_lock array was introduced in MySQL 5.6. (Bug #16263167)
InnoDB: Internal read operations could be misclassified as synchronous when they were actually asynchronous. When the I/O requests returned sooner than expected, threads could be scheduled inefficiently. This issue mainly affected read-ahead requests, and thus had relatively little impact on I/O performed by user queries. (Bug #16249505, Bug #68197)
InnoDB:
The lock_validate
function, which is only
present in debug builds, acquired and released mutexes to avoid
hogging them. This behavior introduced a window wherein changes
to the hash table could occur while code traversed the same set
of data. This fix updates lock_validate
logic
to collect all records for which locks must be validated,
releases mutexes, and runs a loop to validate record locks.
(Bug #16235056)
InnoDB:
ALTER TABLE
functions would
perform a check to see if InnoDB is in read-only mode
(srv_read_only_mode=true
). If InnoDB was in
read-only mode, the check would return a successful status and
do nothing else. This fix replaces
srv_read_only_mode
check conditions with
debug assertions.
(Bug #16227539)
InnoDB:
When the InnoDB buffer pool is almost filled with 4KB compressed
pages, inserting into 16KB compact tables would cause 8KB
pages_free
to increase, which could
potentially slow or stall inserts.
(Bug #16223169)
InnoDB:
This fix updates InnoDB code in ha_innodb.cc
and handler0alter.cc
to use
TABLE::key_info
instead of both
TABLE::key_info
and
TABLE_SHARE::key_info
.
(Bug #16215361)
InnoDB: When InnoDB locking code was revised, a call to register lock waits was inadvertently removed. This fix adds the call back to the InnoDB locking code. (Bug #16208201)
InnoDB:
If the MySQL server halted at a precise moment when a purge
operation was being applied from the
change buffer, the
operation could be incorrectly performed again during the next
restart. A workaround was to set the configuration option
innodb_change_buffering=changes
,
to turn off change buffering for purge operations.
(Bug #16183892, Bug #14636528)
InnoDB: The InnoDB memcached plugin could encounter a serious error under a heavy load, such as produced by benchmark runs. (Bug #16182660, Bug #68096)
InnoDB:
A direct call to the
trx_start_if_not_started_xa_low()
function
would cause a debug assertion.
(Bug #16178995)
InnoDB:
In the case of LOCK WAIT for an insert in a foreign key table,
InnoDB
could report a false
dictionary-changed error and cause the insert to fail rather
than being retried.
(Bug #16174255)
InnoDB:
An in-place ALTER TABLE
on an
InnoDB
table could fail to delete the
statistics for the old primary key from the
mysql.innodb_index_stats
table.
(Bug #16170451)
InnoDB: In some cases, deadlock detection did not work, resulting in sessions hanging waiting for a lock-wait timeout. (Bug #16169638)
InnoDB:
Arithmetic underflow during page compression for
CREATE TABLE
on an
InnoDB
table could cause a server exit.
(Bug #16089381)
InnoDB:
For debug builds, online ALTER
TABLE
operations for InnoDB
tables
could cause a server exit during table rebuilding.
(Bug #16063835)
InnoDB:
In some cases, the InnoDB
purge coordinator
did not use all available purge threads, resulting in suboptimal
purge activity.
(Bug #16037372)
InnoDB:
On systems that cannot handle unaligned memory access, depending
on the stack frame alignment, a SIGBUS
error
could occur during startup. This issue was observed on Solaris
64-bit systems.
(Bug #16021177)
InnoDB:
ALTER TABLE
for
InnoDB
tables was not fully atomic.
(Bug #15989081)
InnoDB:
When innodb_mirrored_log_groups
was set to a value other than the default 1, the MySQL server
encountered a serious error during startup while loading the
InnoDB memcached plugin. In earlier releases, the server would
refuse to start (but not display an error) when this setting was
changed. This fix cleans up the error handling for unsupported
values of this configuration option.
(Bug #15907954, Bug #67670)
InnoDB:
The innodb_sync_array_size
variable was incorrectly allowed to be configured at runtime. As
documented,
innodb_sync_array_size
must be
configured when the MySQL instance is starting up, and cannot be
changed afterward. This fix changes
innodb_sync_array_size
to a
non-dynamic variable, as intended.
(Bug #14629979)
InnoDB:
An error at the filesystem level, such as too many open files,
could cause an unhandled error during an
ALTER TABLE
operation. The error
could be accompanied by Valgrind warnings, and by this assertion
message:
Assertion `! is_set()' failed. mysqld got signal 6 ;
(Bug #14628410, Bug #16000909)
InnoDB:
The server could exit during an attempt by
InnoDB
to reorganize or compress a compressed
secondary index page.
(Bug #14606334)
InnoDB:
A DML operation performed while a RENAME
TABLE
operation waits for pending I/O operations on
the tablespace to complete would result in a deadlock.
(Bug #14556349)
InnoDB:
A RENAME TABLE
statement could
stall for several minutes before timing out. This issue could
occurred for a table using
compression, with
change buffering
enabled.
(Bug #14556349)
InnoDB:
If the server was started with the
skip-innodb
option, or InnoDB
otherwise failed to start,
query any of these Information Schema tables would cause a
severe error:
(Bug #14144290)
InnoDB:
Online DDL had a
restriction that prevented renaming a column and adding a
foreign key involving that column in a single
ALTER TABLE
statement. Now, this
combination of operations is allowed in a single statement.
(Bug #14105491)
InnoDB:
When printing out long semaphore wait diagnostics,
sync_array_cell_print()
ran into a
segmentation violation (SEGV) caused by a race condition. This
fix addresses the race condition by allowing the cell to be
freed while it is being printed.
(Bug #13997024)
InnoDB:
The value of the innodb_version
variable was not updated consistently for all server releases
for the InnoDB Plugin in MySQL 5.1, and the integrated
InnoDB
component in MySQL 5.5, 5.6, and
higher. Since InnoDB
and MySQL Server
development cycles are fully integrated and synchronized, now
the value returned by the
innodb_version
variable is the
same as for the version
variable.
(Bug #13463493, Bug #63435)
InnoDB:
Attempting to replace the default InnoDB
full-text search (FTS) stopword list by creating an
InnoDB
table with the same structure as
INFORMATION_SCHEMA.INNODB_FT_DEFAULT_STOPWORD
would result in an error. SHOW CREATE
TABLE
revealed that the new InnoDB
table was created with CHARSET=utf8
. The
InnoDB
FTS stopword table validity check only
supported latin1. This fix extends the validity check for all
supported character sets.
(Bug #68450, Bug #16373868)
InnoDB:
This fix removes left-over prototype code for
srv_parse_log_group_home_dirs
, and related
header comments.
(Bug #68133, Bug #16198764)
InnoDB: Killing a query caused an InnoDB assertion failure when the same table (cursor) instance was used again. This is the result of a regression error introduced by the fix for Bug#14704286. The fix introduced a check to handle kill signals for long running queries but the cursor was not restored to the proper state. (Bug #68051, Bug #16088883)
InnoDB: On startup, InnoDB reported a message on 64-bit Linux and 64-bit Windows systems stating that the CPU does not support crc32 instructions. On Windows, InnoDB does not use crc32 instructions even if supported by the CPU. This fix revises the wording of the message and implements a check for availability of crc32 instructions. (Bug #68035, Bug #16075806)
InnoDB:
The length of internally generated foreign key names was not
checked. If internally generated foreign key names were over the
64 character limit, this resulted in invalid DDL from
SHOW CREATE TABLE
. This fix checks the length
of internally generated foreign key names and reports an error
message if the limit is exceeded.
(Bug #44541, Bug #11753153)
Partitioning:
ALGORITHM =
INPLACE
, which was disallowed in MySQL 5.6.10 for DDL
statements operating on partitioned tables, can once again be
used with such statements.
(Bug #16216513)
References: See also: Bug #14760210.
Partitioning:
A query on a table partitioned by range and using
TO_DAYS()
as a partitioing
function always included the first partition of the table when
pruning. This happened regardless of the range employed in the
BETWEEN
clause of such a query.
(Bug #15843818, Bug #49754)
Partitioning:
Execution of
ALTER
TABLE ... DROP PARTITION
against a view caused the
server to crash, rather than fail with an error as expected.
(Bug #14653504)
Partitioning:
A query result was not sorted if both
DISTINCT
and ORDER BY
were
used and the underlying table was partitioned.
(Bug #14058167)
Partitioning:
Inserting any number of rows into an
ARCHIVE
table that used more than
1000 partitions and then attempting to drop the table caused the
MySQL Server to fail.
(Bug #13819630, Bug #64580)
Replication: When using GTIDs and binary log auto-positioning, the master had to scan all binary logs whenever the slave reconnected (due to reasons such as I/O thread failure or a change of master) before it could send any events to slave. Now, the master starts from the oldest binary log that contains any GTID not found on the slave. (Bug #16340322, Bug #68386)
Replication: When the server version of the master was greater than or equal to 10, replication to a slave having a lower server version failed. (Bug #16237051, Bug #68187)
Replication: When replicating to a MySQL 5.6 master to an older slave, Error 1193 (ER_UNKNOWN_SYSTEM_VARIABLE) was logged with a message such as Unknown system variable 'SERVER_UUID' on master, maybe it is a *VERY OLD MASTER*. This message has been improved to include more information, similar to this one: Unknown system variable 'SERVER_UUID' on master. A probable cause is that the variable is not supported on the master (version: 5.5.31), even though it is on the slave (version: 5.6.11). (Bug #16216404, Bug #68164)
Replication:
When MTS is on and transactions are being applied, the slave
coordinator would hang when encountering a checksum error on a
transaction event. This was due to a deadlock situation in which
the coordinator assumed a normal stop while a worker waited for
the coordinator to dispatch more events. For debug builds, the
problem appeared as an assertion failure, which was due to the
coordinator not setting thd->is_error()
when encountering an error.
(Bug #16210351)
Replication:
A zero-length name for a user variable (such as
@``
) was incorrectly considered to be a sign
of data or network corruption when reading from the binary log.
(Bug #16200555, Bug #68135)
Replication:
mysqlbinlog can connect to a remote server
and read its binary logs. In MySQL 5.6 and later, this tool can
also wait for the server to generate and send additional events,
in practice behaving like a slave connecting to a master. In
cases where the server sent a heartbeat,
mysqlbinlog was unable to handle it properly.
As a consequence, mysqlbinlog failed at this
point, without reading any more events from the server. To fix
this problem, mysqlbinlog now ignores any
binary log events of type HEARTBEAT_LOG_EVENT
that it receives.
(Bug #16104206)
Replication:
STOP SLAVE
could cause a deadlock
when issued concurrently with a statement such as
SHOW STATUS
that retrieved the
values for one or more of the status variables
Slave_retried_transactions
,
Slave_heartbeat_period
,
Slave_received_heartbeats
,
Slave_last_heartbeat
, or
Slave_running
.
(Bug #16088188, Bug #67545)
References: See also: Bug #16088114.
Replication:
Backtick (`
) characters were not always
handled correctly in internally generated SQL statements, which
could sometimes lead to errors on the slave.
(Bug #16084594, Bug #68045)
References: This issue is a regression of: Bug #14548159, Bug #66550.
Replication:
In order to provision or to restore a server using GTIDs, it is
possible to set gtid_purged
to
a given GTID set listing the transactions that were imported.
This operation requires that the global
gtid_executed
and
gtid_purged
server system
variables are empty. (This is done in order to avoid the
possibility of overriding server-generated GTIDs.)
The error message GTID_PURGED can only be set when GTID_EXECUTED is empty that was raised when this requirement was not met could be confusing or misleading because it did not specify the scope of the affected variables. To prevent this from happening, error messages that refer to variables relating to GTIDs now specify the scope of any such variables when they do so. (Bug #16084426, Bug #68038)
Replication:
The session-level value for
gtid_next
was incorrectly reset
on the slave for all rollbacks, which meant that GTIDs could be
lost for multi-statement transactions, causing the slave to stop
with an ER_GTID_NEXT_TYPE_UNDEFINED_GROUP
error. Now this is done only when a complete transaction is
being rolled back, or when
autocommit
is enabled.
(Bug #16084206)
Replication:
Using the --replicate-*
options (see
Replica Server Options and Variables) could in some
cases lead to a memory leak on the slave.
(Bug #16056813, Bug #67983)
Replication: In some cases, when the slave could not recognize the server version of the master, this could cause the slave to fail. (Bug #16056365)
Replication:
In certain cases, the dump thread could send a heartbeat out of
synchronisation with format description events. One of the
effects of this issue what that, after provisioning a new server
from a backup data directory and setting
--gtid-mode=ON
and enabling
autopositioning (see CHANGE MASTER TO Statement),
replication failed to start, with the error Read
invalid event from master.... The same problem could
also cause GTID-based replication to fail due to skipped events
following a unplanned shutdown of the master.
(Bug #16051857)
Replication:
Table IDs used in replication were defined as type
ulong
on the master and
uint
on the slave. In addition, the maximum
value for table IDs in binary log events is 6 bytes
(281474976710655). This combination of factors led to the
following issues:
Data could be lost on the slave when a table was assigned an
ID greater than uint
.
Table IDs greater than 281474976710655 were written to the binary log as 281474976710655.
This led to a stopped slave when the slave encountered two tables having the same table ID.
To fix these problems, IDs are now defined by both master and
slave as type ulonglong
but constrained to a
range of 0 to 281474976710655, restarting from 0 when it exceeds
this value.
(Bug #14801955, Bug #67352)
Replication: Internal objects used for relay log information were only partially deleted before freeing their memory. (Bug #14677824)
Replication: It was possible in certain cases—immediately after detecting an EOF in the dump thread read event loop, and before deciding whether to change to a new binary log file—for new events to be written to the binary log before this decision was made. If log rotation occurred at this time, any events that occurred following EOF detection were dropped, resulting in loss of data. Now in such cases, steps are taken to make sure that all events are processed before allowing the log rotation to take place. (Bug #13545447, Bug #67929)
References: See also: Bug #16016886.
Replication: If the disk becomes full while writing to the binary log, the server hangs until space is freed up manually. It was possible after this was done for the MySQL server to fail, due to an internal status value being set when not needed. Now in such cases, rather than trying to set this status, a warning is written in the error log instead. (Bug #11753923, Bug #45449)
Microsoft Windows:
A server started with
--shared-memory
to support
shared-memory connections could crash when receiving requests
from multiple threads.
(Bug #13934876)
Solaris: mysql_install_db did not work in Solaris 10 sparse root zones. (Bug #68117, Bug #16197860)
InnoDB
now reports row and table locks to the
thread pool plugin. Deadlocks within a thread group could occur
otherwise.
(Bug #16448639)
Failure to handle a full-text search wildcard properly could cause the server to exit. (Bug #16446108)
SHOW ENGINE PERFORMANCE_SCHEMA STATUS
could
report incorrect memory-allocation values when the correct
values exceeded 4GB.
(Bug #16414644)
The server could exit if a prepared statement attempted to create a table using the name of an existing view while an SQL handler was opened. (Bug #16385711)
Performance Schema statement tokenization overhead was reduced. (Bug #16382260)
A long database name in a GRANT
statement could cause the server to exit.
(Bug #16372927)
On Linux, a race condition involving epoll()
could cause the thread pool plugin to miss events. This was most
likely on systems with greater than 16 cores.
(Bug #16367483)
Some aggregate queries attempted to allocate excessive memory. (Bug #16343992)
For debug builds, an assertion could be raised if a statement
failed with autocommit enabled just before an
XA START
statement
was issued.
(Bug #16341673)
Very small join_buffer_size
values could cause an assertion to be raised.
(Bug #16328373)
The BUILD-CMAKE
file in MySQL distributions
was updated with the correct URL for CMake
information.
(Bug #16328024)
The optimizer's attempt to remove redundant subquery clauses
raised an assertion when executing a prepared statement with a
subquery in the ON
clause of a join in a
subquery.
(Bug #16318585)
References: This issue is a regression of: Bug #15875919.
Incorrect results were returned if a query contained a subquery
in an IN
clause which contained an
XOR
operation in the
WHERE
clause.
(Bug #16311231)
A Valgrind failure could occur if a CREATE
USER
statement was logged to the general query log and
the old_passwords
system
variable was set to 2.
(Bug #16300620)
For debug builds, checking of password constraints could raise an assertion for statements that updated passwords. (Bug #16289303)
Conversion of numeric values to
BIT
could yield unexpected
results.
(Bug #16271540)
Fixed warnings when compiling with XCode 4.6. Fixed warnings
when compiling when the _XOPEN_SOURCE
or
isoctal
macro was already defined in the
environment.
(Bug #16265300, Bug #60911, Bug #12407384)
In the range optimizer, an index merge failure could cause a server exit. (Bug #16241773)
For upgrade operations, RPM packages produced unnecessary errors
about being unable to access .err
files.
(Bug #16235828)
Queries using range predicates that were evaluated using the LooseScan semijoin strategy could return duplicate rows. (Bug #16221623)
References: This issue is a regression of: Bug #14728469.
Certain legal HAVING
clauses were rejected as
invalid.
(Bug #16221433)
yaSSL did not perform proper padding checks, but instead examined only the last byte of cleartext and used it to determine how many bytes to remove. (Bug #16218104)
The Performance Schema could return incorrect values for the
PROCESSLIST_INFO
column of the
threads
table.
(Bug #16215165)
A full-text query using Boolean mode could return zero results in some cases where the search term was a quoted phrase:
If the quoted phrase was preceded by a + sign. For example, this combination of a Boolean + operator and a phrase would return zero results:
WHERE MATCH(content) AGAINST('+"required term due to plus sign"' IN BOOLEAN MODE)
If the quoted phrase contained any stopwords. For example, the stopword "the" inside the phrase caused the query to return zero results:
WHERE MATCH(content) AGAINST('"stopword inside the phrase"' IN BOOLEAN MODE)
(Bug #16206253, Bug #68150)
mysql_config --libs displayed incorrect output. (Bug #16200717)
Invocation of the range optimizer for a NULL
select caused the server to exit.
(Bug #16192219)
If, in a SELECT
, the
HAVING
clause contained a function call which
itself contained an alias to a selected expression, the server
could sometimes exit.
(Bug #16165981)
For debug builds, the server could exit due to incorrect
calculation of applicable indexes for a join that involved
const
tables.
(Bug #16165832)
A bug in range optimization sometimes led to incorrect condition calculation for index merge union. This could lead to missing rows. (Bug #16164031, Bug #68194, Bug #16229746)
For a CREATE TABLE (...
statement for which
the col_name
TIMESTAMP DEFAULT
CURRENT_TIMESTAMP ...) ... SELECTSELECT
did not provide a value for the
TIMESTAMP
column, that column was set to
'0000-00-00 00:00:00', not the current timestamp.
(Bug #16163936)
Using GROUP BY WITH ROLLUP
in a prepared
statement could cause the server to exit.
(Bug #16163596)
With the thread pool plugin enabled, large numbers of connections could lead to a Valgrind panic or failure of clients to be able to connect. (Bug #16088658, Bug #16196591)
Performance Schema instrumentation was missing for slave worker threads. (Bug #16083949)
The server executed
EXPLAIN
FORMAT=JSON
for some malformed queries improperly.
(Bug #16078557)
With statement-based binary logging, dropping a
TEMPORARY
InnoDB
table
could cause a segmentation fault.
(Bug #16076275)
Setting the
slave_rows_search_algorithms
system variable to an inappropriate value could cause the server
to exit.
(Bug #16074161)
SET PASSWORD
and
GRANT ... IDENTIFIED
BY
have no effect on the password of a user who is
authenticated using an authentication plugin that accesses
passwords stored externally to the mysql.user table. But
attempts to change the password of such a user produced no
warning, leading to the impression that the password had been
changed when it was not. Now MySQL issues an
ER_SET_PASSWORD_AUTH_PLUGIN
warning to indicate that the attempt was ignored.
(Bug #16072004)
Directory name manipulation could result in stack overflow on OS X and Windows. (Bug #16066243)
The initial test
database contained a
dummy.bak
file that prevented DROP
DATABASE
from working. This file is no longer
included. Also, a db.opt
file is now included
that contains these lines:
default-character-set=latin1 default-collation=latin1_swedish_ci
(Bug #16062056)
Issuing a PREPARE
statement using certain
combinations of stored functions and user variables caused the
server to exit.
(Bug #16056537)
Setting a system variable to DEFAULT
could
cause the server to exit.
(Bug #16044655)
For debug builds, if the server was started with binary logging
disabled, executing SHOW RELAYLOG
EVENTS
from within a stored procedure raised an
assertion.
(Bug #16043173)
The query parser leaked memory for some syntax errors. (Bug #16040022)
During shutdown, the server could attempt to lock an uninitialized mutex. (Bug #16016493)
The --default-authentication-plugin
option
permitted invalid plugin values, and did not always set the
old_passwords
system variable to a value
appropriate for the named plugin.
(Bug #16014394)
The --character-set-server
option
could set connection character set system variables to values
such as ucs2
that are not permitted.
(Bug #15985752, Bug #23303391)
Under some circumstances, mysql --secure-auth permitted passwords to be sent to the server using the old (pre-4.1) hashing format. (Bug #15977433)
When a partition is missing, code in
ha_innodb.cc
would retry 10 times and sleep
for a microsecond each time while holding
LOCK_open
. The retry logic for partitioned
tables was introduced as a fix for Bug#33349 but did not include
a test case to validate it. This fix removes the retry logic for
partitioned tables. If the problem reported in Bug#33349
reappears, a different solution will be explored.
(Bug #15973904)
Joins of exactly 32 tables and containing a
HAVING
clause returned an empty result.
(Bug #15972635)
A mysys
library string-formatting routine
could mishandle width specifiers.
(Bug #15960005)
Table creation operations added entries to the
file_instances
Performance Schema
table, but these were not always removed for table drop
operations.
(Bug #15927620)
With index condition pushdown enabled, queries for which the pushed-down condition contained no columns in the used index could be slow. (Bug #15896009)
A query with an EXISTS/IN/ALL/ANY
subquery
with an ORDER BY
clause ordering by an outer
column of type BLOB
that is not in the select
list caused an assertion to fire.
(Bug #15875919)
References: See also: Bug #14728142.
In special cases, the optimizer did not consider indexes that
were applicable to query processing, resulting in potentially
suboptimal execution and incorrect
EXPLAIN
output.
(Bug #15849135, Bug #16094171)
Creating an InnoDB
table with a
FULLTEXT
index could encounter a serious
error if the table name contained nonalphanumeric characters.
(Bug #14835178, Bug #16036699)
Enabling the query cache during high client contention could cause the server to exit. (Bug #14727815)
The MSI Installer installed MySQL in “per-user” mode, which could result in conflicts or failure to detect an existing installation if two users installed MySQL on the same machine. Now the MSI Installer uses “per-machine” installation mode. (Bug #14711808)
The server sometimes failed to respect
MAX_CONNECTIONS_PER_HOUR
limits on user
connections.
(Bug #14627287)
The optimizer could return incorrect results after transforming
an IN
subquery with aggregate functions to an
EXISTS
subquery.
(Bug #14586710)
SET PASSWORD
for anonymous users
did not work correctly.
(Bug #14561102)
When a client program loses the connection to the MySQL server
or if the server begins a shutdown after the client has executed
mysql_stmt_prepare()
, the next
mysql_stmt_prepare()
returns an
error (as expected) but subsequent
mysql_stmt_execute()
calls crash
the client.
(Bug #14553380)
Previously, if multiple --login-path
options
were given, mysql_config_editor ignored all
but the last one. Now multiple --login-path
options result in an error.
(Bug #14551712)
SHOW COLUMNS
on a view defined as
a UNION
of
Geometry
columns could cause the server to
exit.
(Bug #14362617)
The
sha256_password_private_key_path
and
sha256_password_public_key_path
system variables indicate key files for the
sha256_password
authentication plugin, but
the server failed to properly check whether the key files were
valid. Now in the event that either key file is invalid, the
server logs an error and exits.
(Bug #14360513)
SET
could
cause the server to exit. This syntax is now prohibited because
in var_name
=
VALUES(col_name
)SET
context there is no column name and
the statement returns
ER_BAD_FIELD_ERROR
.
(Bug #14211565)
The COM_CHANGE_USER
command in the
client/server protocol did not properly use the character set
number in the command packet, leading to incorrect character set
conversion of other values in the packet.
(Bug #14163155)
Invoking the FORMAT()
function
with a locale and a very large number could cause the server to
exit.
(Bug #14040155)
yaSSL rejected some valid server SSL certificates. (Bug #13777928)
Certain plugin-related conditions can make a user account unusable:
The account requires an authentication plugin that is not loaded.
The account requires the sha256_password
authentication plugin but the server was started with
neither SSL nor RSA enabled as required by this plugin.
The server now checks those conditions by default and produces
warnings for unusable accounts. This checking slows down server
initialization and FLUSH PRIVILEGES
, so it is
made optional by means of the new
validate_user_plugins
system variable. This
variable is enabled by default, but if you do not require the
additional checking, you can disable it at startup to avoid the
performance decrement.
(Bug #13010061, Bug #14506305)
Passing an unknown time zone specification to
CONVERT_TZ()
resulted in a memory
leak.
(Bug #12347040)
The obsolete linuxthreads.txt
and
glibc-2.2.5.patch
files in the
Docs
directory of MySQL distributions have
been removed.
(Bug #11766326)
mysql_install_db did not escape
'_'
in the host name for statements written
to the grant tables.
(Bug #11746817)
With
explicit_defaults_for_timestamp
enabled, inserting NULL
into a
TIMESTAMP NOT NULL
column now produces an
error (as it already did for other NOT NULL
data types), instead of inserting the current timestamp.
(Bug #68472, Bug #16394472)
Handling of SQL_CALC_FOUND_ROWS
in
combination with ORDER BY
and
LIMIT
could lead to incorrect results for
FOUND_ROWS()
.
(Bug #68458, Bug #16383173)
If INET6_NTOA()
or
INET6_ATON()
returned
NULL
for a row in a result set, following
rows also returned NULL
.
(Bug #68454, Bug #16373973)
A statement with an aggregated, nongrouped outer query and an
aggregated, nongrouped subquery in the SELECT
list could return incorrect results.
(Bug #68372, Bug #16325175)
Adding an ORDER BY
clause following an
IN
subquery could cause duplicate rows to be
returned.
(Bug #68330, Bug #16308085)
If the server was started with
--skip-grant-tables
,
ALTER USER ... PASSWORD EXPIRE
caused the
server to exit.
(Bug #68300, Bug #16295905)
Configuring with -DWITH_SSL=/path/to/openssl
resulted in link errors due to selection of the incorrect
libcrypto
.
(Bug #68277, Bug #16284051)
If mysql is built with the bundled
libedit
library, the library is built as
static code, to avoid linking to a different dynamic version at
runtime. Dynamic linking could result in use of a different,
incompatible version and a segmentation fault.
(Bug #68231, Bug #16296509)
Some table I/O performed by the server when calling a storage engine were missing from the statistics collected by the Performance Schema. (Bug #68180, Bug #16222630)
The Perl version of mysql_install_db mishandled some error messages. (Bug #68118, Bug #16197542)
For arguments with fractional seconds greater than six decimals,
SEC_TO_TIME()
truncated, rather
than rounding as it should have.
(Bug #68061, Bug #16093024)
Queries with many values in a IN()
clause
were slow due to inclusion of debugging code in non-debugging
builds.
(Bug #68046, Bug #16078212)
References: See also: Bug #58731, Bug #11765737.
ALTER TABLE
inserted
tbl_name
ADD
COLUMN col_name
TIMESTAMP DEFAULT
CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP0000-00-00 00:00:00
rather than the current
timestamp if the alteration was done in place rather than by
making a table copy.
(Bug #68040, Bug #16076089)
mysqld_safe used the nonportable
-e
test construct.
(Bug #67976, Bug #16046140)
Nonspatial indexes only support exact-match lookups for spatial
columns, but the optimizer incorrectly used
range
access in some cases,
leading to incorrect results.
(Bug #67889, Bug #15993693)
For EXPLAIN DELETE
and EXPLAIN
UPDATE
the possible_keys
column
listed all indexes, not just the applicable indexes.
(Bug #67830, Bug #15972078)
MySQL failed to build if configured with
WITH_LIBWRAP
enabled.
(Bug #67018, Bug #16342793)
CMake did not check whether the system
zlib
had certain functions required for
MySQL, resulting in build errors. Now it checks and falls back
to the bundled zlib
if the functions are
missing.
(Bug #65856, Bug #14300733)
If a dump file contained a view with one character set and collation defined on a view with a different character set and collation, attempts to restore the dump file failed with an “illegal mix of collations” error. (Bug #65382, Bug #14117025)
If the server was started without a
--datadir
option,
SHOW VARIABLES
could show an
empty value for the datadir
system variable.
(Bug #60995, Bug #12546953)
For debug builds, some queries with SELECT ... FROM
DUAL
nested subqueries raised an assertion.
(Bug #60305, Bug #11827369)
The --log-slow-admin-statements
and --log-slow-slave-statements
command options now are exposed at runtime as the
log_slow_admin_statements
and
log_slow_slave_statements
system variables. Their values can be examined using
SHOW VARIABLES
. The variables are
dynamic, so their values can be set at runtime. (The options
were actually replaced by the system
variables, but as system variables can be set at server startup,
no option functionality is lost.)
(Bug #59860, Bug #11766693)
UNION ALL
on
BLOB
columns could produce
incorrect results.
(Bug #50136, Bug #11758009)
An out-of-memory condition could occur while handling an out-of-memory error, leading to recursion in error handling. (Bug #49514, Bug #11757464)
The REPLACE()
function produced
incorrect results when a user variable was supplied as an
argument and the operation was performed on multiple rows.
(Bug #49271, Bug #11757250)
UNION
type conversion could
incorrectly turn unsigned values into signed values.
(Bug #49003, Bug #11757005)
Setting max_connections
to a
value less than the current number of open connections caused
the server to exit.
(Bug #44100, Bug #11752803)
The optimizer used Loose Index Scan for some queries for which this access method is inapplicable. (Bug #42785, Bug #11751794)
View access in low memory conditions could raise a debugging assertion. (Bug #39307, Bug #11749556)