Dear MySQL users,
MySQL Server 5.7.20, a new version of the popular Open Source
Database Management System, has been released. MySQL 5.7.20 is
recommended for use on production systems.
For an overview of what's new in MySQL 5.7, please see
http://dev.mysql.com/doc/refman/5.7/en/mysql-nutshell.html
For information on installing MySQL 5.7.20 on new servers, please see
the MySQL installation documentation at
http://dev.mysql.com/doc/refman/5.7/en/installing.html
MySQL Server 5.7.20 is available in source and binary form for a number of
platforms from our download pages at
http://dev.mysql.com/downloads/mysql/
MySQL Server 5.7.20 is also available from our repository for Linux
platforms, go here for details:
http://dev.mysql.com/downloads/repo/
Windows packages are available via the Installer for Windows or .ZIP
(no-install) packages for more advanced needs. The point and click
configuration wizards and all MySQL products are available in the
unified Installer for Windows:
http://dev.mysql.com/downloads/installer/
5.7.20 also comes with a web installer as an alternative to the full
installer.
The web installer doesn't come bundled with any actual products
and instead relies on download-on-demand to fetch only the
products you choose to install. This makes the initial download
much smaller but increases install time as the individual products
will need to be downloaded.
We welcome and appreciate your feedback, bug reports, bug fixes,
patches, etc.:
http://bugs.mysql.com/report.php
The following link lists the changes in the MySQL 5.7 since the
the release of MySQL 5.7.19.
http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-20.html
Enjoy!
Changes in MySQL 5.7.20 (2017-10-16)
Audit Log Notes
* Event-matching filter rules for the audit_log plugin now
support an abort element, which can be used to prevent
qualifying events from executing. For more information,
see Audit Log Filtering
(http://dev.mysql.com/doc/refman/5.7/en/audit-log-filtering.html).
This capability can be used, for example, to
augment the capabilities of MySQL Enterprise Firewall,
which blocks SQL statements on a per-user basis, by
writing audit filtering rules that match statements and
block them based on characteristics of the statements
themselves.
Deprecation and Removal Notes
* Previously, the --transaction-isolation and
--transaction-read-only server startup options
corresponded to the tx_isolation and tx_read_only system
variables. For better name correspondence between startup
option and system variable names, transaction_isolation
and transaction_read_only have been created as aliases
for tx_isolation and tx_read_only. The tx_isolation and
tx_read_only variables are now deprecated and will be
removed in MySQL 8.0. Applications should be adjusted to
use transaction_isolation and transaction_read_only
instead.
* The query cache is now deprecated and is removed in MySQL
8.0. Deprecation includes these items:
+ The FLUSH QUERY CACHE and RESET QUERY CACHE
statements.
+ The SQL_CACHE and SQL_NO_CACHE SELECT modifiers.
+ These system variables: have_query_cache,
ndb_cache_check_time, query_cache_limit,
query_cache_min_res_unit, query_cache_size,
query_cache_type, query_cache_wlock_invalidate.
+ These status variables: Qcache_free_blocks,
Qcache_free_memory, Qcache_hits, Qcache_inserts,
Qcache_lowmem_prunes, Qcache_not_cached,
Qcache_queries_in_cache, Qcache_total_blocks.
* The mysql client by default strips comments in statements
sent to the server, and this behavior is controlled using
--skip-comments (strip comments), and --comments
(preserve comments).
Comment stripping is now deprecated. This feature and the
options to control it will be removed in a future MySQL
release.
* These syntax constructs for table and column references
are now deprecated and will be removed in a future
version of MySQL. Instances of these constructs should be
changed to remove the leading period.
+ .col_name
+ .tbl_name
+ .tbl_name.col_name
Installation Notes
* For platforms that use systemd (see Managing MySQL Server
with systemd
(http://dev.mysql.com/doc/refman/5.7/en/using-systemd.html)),
the data directory is initialized if empty at server
startup. This might be a problem if the data directory is
a remote mount that has temporarily disappeared: The
mount point would appear to be an empty data directory,
which then would be initialized as a new data directory.
It is now possible to suppress this automatic
initialization behavior. specify the following line in
the /etc/sysconfig/mysql file (create the file if it does
not exist):
NO_INIT=true
(Bug #26595288, Bug #87287)
Packaging Notes
* mysqlcheck was missing in the MySQL Server Docker image,
which prevented mysql_upgrade from running. (Bug
#26400146, Bug #86968)
Security Notes
* Certificates automatically generated by mysqld and
mysql_ssl_rsa_setup now use X509 v3 rather than v1. (Bug
#26521654)
* The keyring_okv plugin now supports password-protecting
the key file used for secure connections. See Using the
keyring_okv KMIP Plugin
(http://dev.mysql.com/doc/refman/5.7/en/keyring-okv-plugin.html).
X Plugin Notes
* A Mysqlx.Connection.CapabilitiesGet request using MySQL X
Protocol did not return the complete list of available
authentication mechanisms. (Bug #26044113)
* For mixed case or uppercase schema names, the statement
list_objects could incorrectly report a collection as a
table. (Bug #25769683)
* The X Plugin was omitted from the list of plugins to
include for testing data directory permissions. (Bug
#24823999)
Functionality Added or Changed
* Replication: In previous versions issuing STOP
GROUP_REPLICATION stopped the plugin but the server still
accepted transactions. This meant the transactions were
not transmitted to the group. To make STOP
GROUP_REPLICATION safer, now super_read_only is set to ON
immediately upon issuing STOP GROUP_REPLICATION, which
ensures no transactions are accepted. (Bug #25495067, Bug
#84795)
* Replication: The group_replication_member_weight variable
has been added which enables you to control the election
of new primaries in single-primary mode. In previous
versions primary election was based on the member's UUID,
with the lowest UUID elected as the new primary in the
event of fail over. Use this variable to assign numeric
weights to members to ensure that specific members are
elected, for example during scheduled maintenance of the
primary or to ensure certain hardware is prioritised.
Bugs Fixed
* InnoDB: Invalid error handling code was removed from a
function related to tablespace import. (Bug #26595476)
* InnoDB: A check for discarded partitions during a DML
operation only checked the first partition. Failure to
check for other discarded partitions caused an assertion
failure. (Bug #25942592)
* InnoDB: Replication lag occurred on slave instances
during large update operations on tables with many
partitions. (Bug #25687813, Bug #85352)
* InnoDB: A failure occurred during an end range
comparison. (Bug #25669686)
* InnoDB: Enabling the innodb_buffer_pool_load_now setting
failed in readonly mode. The event that signals the
buffer pool load thread was not initialized. (Bug
#25586766)
* InnoDB: Test-related code intended to simulate a random
read on a non-existent page raised an invalid assertion.
(Bug #25479538)
References: This issue is a regression of: Bug #25053705.
* InnoDB: A long wait for a dictionary operation lock held
by a full-text search synchronization operation caused a
server exit. (Bug #24938374)
* Partitioning: In certain cases when fetching heap records
a partition ID could be set to zero. (Bug #86255, Bug
#26034430)
* Partitioning: Queries involving NULL were not always
handled correctly on tables that were partitioned by
LIST. (Bug #76418, Bug #20748521)
References: See also: Bug #86255, Bug #26034430.
* Replication: MySQL internal administration commands that
update replication-specific repository tables, for
example during a replication synchronization check using
the mysqlrplsync utility, can now bypass read locks. This
enables such commands to execute regardless of the
settings for the read_only and super_read_only system
variables and the autocommit mode. (Bug #26414532, Bug
#86224)
* Replication: When the Group Replication plugin
Delayed_initialization_thread failed to start due to
unavailable resources, a locked mutex was being kept
behind which would cause issues on
Delayed_initialization_thread destructor. The fix ensures
that the mutex is unlocked when the thread fails to
start. (Bug #26394678)
* Replication: If hostname resolution was not working for a
member in Group Replication, the error returned when
attempting to connect was referring to credentials. The
error message has been improved to describe the problem
with hostname resolution. (Bug #26368004)
* Replication: If the options file contained Group
Replication related settings the server could stop
unexpectedly on start up. (Bug #26314472)
* Replication: FLUSH LOGS attempted to send an OK message
after having already sent an error response during the
commit phase. (Bug #26272158)
* Replication: With some workloads that contained large
inserts, the XCOM transaction cache could consume a large
amount of memory. The fix limits the size of the cache to
reduce the impact to memory usage. (Bug #26241291)
* Replication: Group Replication partition threads were not
visible in the Performance Schema tables. (Bug #26241008)
* Replication: COUNT_TRANSACTIONS_REMOTE_IN_APPLIER_QUEUE
was set to an incorrect value when
group_replication_recovery_complete_at="transactions_cert
ified" on a recovering member. (Bug #26180350)
* Replication: The values of the
group_replication_recovery_use_ssl and
group_replication_recovery_ssl_verify_server_cert
variables were not being updated when configured for the
Group Replication recovery channel. (Bug #26142801)
* Replication: When replicating a partitioned table with an
index, on a replication slave where HASH_SCAN was
specified as part of the slave_rows_search_algorithms
setting, the slave I/O thread sometimes stopped with an
error HA_ERR_KEY_NOT_FOUND. (Bug #26137159)
* Replication: group_replication_force_members could be
used in situations where the group was working properly,
in other words a majority was reachable. This incorrect
use could cause instability in the group. Therefore, its
use has been restricted to the scenario for which it was
created, for forming a new membership from a subset of a
previous group's membership when a majority of the
members are unreachable. (Bug #26093967)
* Replication: The delayed initialization mechanism used
for server starts has been improved. Now, it only blocks
connections until the server is in read mode. (Bug
#26037344)
References: See also: Bug #84731, Bug #25475132.
* Replication: It was possible to set server_uuid to the
same value as group_replication_group_name. Doing so
could result in unexpected behavior because GTIDs are
identified by a UUID. Now it is not possible to set
server_uuid to the same value as
group_replication_group_name. (Bug #26035931)
* Replication: The system variable pseudo_slave_mode, which
is for internal server use, sometimes raised an assertion
when it was changed inside a transaction. The server no
longer changes this variable inside a transaction. (Bug
#26034192, Bug #86250)
* Replication: When a primary member, for example the
primary in single-primary group or in a multi-primary
group, which also had asynchronous replication channels
feeding data into it was stopped, the asynchronous
channels would continue applying changes. Although
super_read_only was being set when STOP GROUP_REPLICATION
was issued, this did not stop any running asynchronous
replication channels which were already running. This
meant that changes could be made locally on the member,
and that the asynchronous replication channels had to be
stopped manually. Now when Group Replication stops,
either due to an error or when STOP GROUP_REPLICATION is
issued, all asynchronous replication channels are
stopped. (Bug #26024253)
* Replication: When write sets are used for parallelization
by a replication slave (as specified by the
binlog_transaction_dependency_tracking system variable),
empty transactions are now ignored, and the handling of
relay log rotation has been optimized. (Bug #25982097)
* Replication: A misleading warning was issued when the
command FLUSH LOGS or PURGE LOGS BEFORE was used on a
binary log file with an expiry time set, and the binary
log file was in use. The warning related to the file
being in use, and implied that a purge attempt had taken
place, even if the expiry time had not yet been reached.
Now, MySQL checks the expiry time of the binary log file
first, and only then checks whether the file is in use.
So the warning is only issued for an in-use binary log
file that is old enough to be purged. (Bug #25973525)
* Replication: Group Replication stopped unexpectedly when
more than 1024 file descriptors were in use. (Bug
#25892493)
* Replication: Now that XA transactions are prepared and
committed in two parts, an issue with statement-based
replication has been identified. If two XA transactions
committed on the master are being prepared on the slave
in the inverse order, locking dependencies can occur that
cannot be safely resolved. The issue is not present with
row-based replication.
XA transactions are therefore now considered unsafe for
statement-based replication.
+ When binlog_format = STATEMENT, a warning is issued
for DML statements inside XA transactions, and
replication might fail with deadlock on slaves.
+ When binlog_format = MIXED, DML statements inside XA
transactions are logged using row-based replication.
+ When binlog_format = ROW, DML statements inside XA
transactions are logged as before.
(Bug #25786490, Bug #85639)
* Replication: If the Group Replication plugin was
uninstalled while a group was running, the plugin was
marked for uninstall. This could cause the server
shutdown to not complete successfully. The fix ensures
that the Group Replication plugin cannot be uninstalled
if the majority of the group cannot be reached. In such a
case it is necessary to issue STOP GROUP_REPLICATION
before uninstalling the plugin. (Bug #25673788)
* Replication: Replication clients no longer enable LOCAL
capability for LOAD DATA statements, because they do not
use LOAD DATA LOCAL statements. (Bug #24763131)
* Replication: In case of a failure while creating multiple
slave applier worker threads, some threads would be left
orphaned and their resources would not be collected.
Thanks to Laurynas Biveinis for his contribution to
fixing this bug. (Bug #24679056, Bug #82980)
* Replication: The binlog_checksum option cannot be changed
within a transaction. MySQL cannot log this statement, as
would be required inside a transaction, while the
requested function is being performed on the binary log.
(Bug #22914463)
* Replication: The logging of Group Replication has been
improved. Now logging includes information when a member
joins or leaves, when the view changes, and so on. (Bug
#84798, Bug #25495393)
* Compiling with -DWITHOUT_SERVER=1 resulted in
my_symlink.c compilation failure due to missing #include
for my_dir.h. Thanks to Christian Hesse for the patch.
(Bug #26495816, Bug #87137)
* yaSSL could incorrectly perform TLS cipher negotiation.
(Bug #26482173)
* The Linux RPM spec file for RHEL6 and higher is updated
with comments that recommend installing the
redhat-rpm-config package to add convenience macros that
make rebuilding the RPM package easier. Thanks to Simon
Mudd for the patch. (Bug #26474153, Bug #87098)
* If the error log was misconfigured and the server could
not start, no output indicating the problem was produced.
(Bug #26447825, Bug #87087)
* mysqld_multi was modified to use mysqld --initialize
rather than the deprecated mysql_install_db. Thanks to
Zhan Shi for the patch. (Bug #26446321, Bug #87080)
* Adding an ORDER BY to a query that included an outer join
and a subquery caused a constant value defined for a
column in the subquery to be incorrectly promoted to a
constant value in the case when the subquery returns 0
rows. (Bug #26432173)
* The server failed to check the maximum path length for
partition names. (Bug #26390632)
* Identifiers containing a mixture of backslashes and
backticks could be parsed incorrectly. (Bug #26372491)
* Source packages for Debian platforms contained prebuilt
debug binaries, causing build failures on any
architectures other than the one on which those binaries
were built. (Bug #26186911)
* The mysqld_pre_systemd script in RPM packages found the
error log setting in option files if specified as
log-error but not as log_error, though both are
permitted. (Bug #26148391, Bug #86466)
* When running mysqlbinlog with the
--read-from-remote-server option, rewrite rules specified
using the --rewrite-db option were ignored, so data was
not written to the target database. (Bug #26117735, Bug
#86288)
* REFERENCES privilege checking could use the incorrect
database in some cases. (Bug #26106655)
* Uninstalling the daemon_memcached plugin caused a serious
error. (Bug #25909540)
* The rpl_diff.inc test case file did not find the data
difference between servers. Thanks to Yura Sorokin for
the patch. (Bug #25860138, Bug #85838)
* An ngram fulltext parser search query returned incorrect
results and raised an assertion. (Bug #25851975)
* Selecting from a view could yield different results with
materialization enabled versus materialization disabled.
(Bug #25782811, Bug #85622)
* The Performance Schema failed to check the maximum host
length for client connections. (Bug #25510805)
* mysqlpump displayed incorrect progress information about
the number of tables dumped. (Bug #25432850)
* Some mysqldump warnings went to the standard output
rather than the standard error output and consequently
were written to the dump file. (Bug #25380000, Bug
#82992)
* LOAD DATA failed to accept multibyte characters that
followed an escape sequence. (Bug #25147988, Bug #83950,
Bug #25865525)
* A server error occurred when a full text search result
exceeded the innodb_ft_result_cache_limit setting. The
patch for this bug also backports a related patch (Bug
#21140111). (Bug #25033538)
* If a stored function was considered a constant by the
optimizer, calling it from a subquery in a NOT IN
condition in the WHERE clause could cause a server exit.
(Bug #23577867)
* A mysqldump memory leak was fixed. Thanks to Yura Sorokin
for the patch. (Bug #23531150, Bug #81714)
* Incorrect results or a server exit could result when a
query used Batched Key Access optimization and a virtual
generated column was part of the join buffer. (Bug
#23169112)
* If a session rolled back to a savepoint and then was
killed, the statements up to the point of the savepoint
could be committed. (Bug #22350047, Bug #79596)
* For clients that used Connector/Python and authenticated
using the sha256_password plugin, the server could handle
connections incorrectly. (Bug #21421642)
On Behalf of the MySQL/Oracle Release Engineering Team,
Hery Ramilison
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