Dear MySQL users,

MySQL Server 5.7.23, a new version of the popular Open Source
Database Management System, has been released. MySQL 5.7.23 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 5.7.23 on new servers, please see
the MySQL installation documentation at

http://dev.mysql.com/doc/refman/5.7/en/installing.html

MySQL Server 5.7.23 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 5.7.23 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/

5.7.23 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 release of MySQL 5.7.22. It may also be viewed
online at

http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-23.html

Enjoy!

Changes in MySQL 5.7.23 (2018-07-27, General Availability)

Audit Log Notes


* For new MySQL installations, the USER and HOST columns in
the audit_log_user table used by MySQL Enterprise Audit
now have definitions that better correspond to the
definitions of the User and Host columns in the
mysql.user system table.
For upgrades to an installation for which MySQL
Enterprise Audit is already installed, it is recommended
that you alter the table definitions as follows:
ALTER TABLE mysql.audit_log_user
DROP FOREIGN KEY audit_log_user_ibfk_1;
ALTER TABLE mysql.audit_log_filter
ENGINE=InnoDB;
ALTER TABLE mysql.audit_log_filter
CONVERT TO CHARACTER SET utf8 COLLATE utf8_bin;
ALTER TABLE mysql.audit_log_user
ENGINE=InnoDB;
ALTER TABLE mysql.audit_log_user
CONVERT TO CHARACTER SET utf8 COLLATE utf8_bin;
ALTER TABLE mysql.audit_log_user
MODIFY COLUMN USER VARCHAR(32);
ALTER TABLE mysql.audit_log_user
ADD FOREIGN KEY (FILTERNAME) REFERENCES mysql.audit_log_filter(NAME);
(Bug #23706056)

Compilation Notes


* Solaris: MySQL now can be compiled on Solaris using gcc.
(Bug #27802681)

MySQL Enterprise Notes


* The MySQL Enterprise Firewall firewall_whitelist table
now contains a primary key column named ID. (Bug
#27164826)

Security Notes


* The linked OpenSSL library for the MySQL Commercial
Server has been updated to version 1.0.2o. Issues fixed
in the new OpenSSL version are described at
http://www.openssl.org/news/vulnerabilities.html.
This change does not affect the Oracle-produced MySQL
Community build of MySQL Server, which uses the yaSSL
library instead. (Bug #28025379)

* In MySQL 5.7, the default authentication plugin is
mysql_native_password. As of MySQL 8.0, the default
authentication plugin is changed to
caching_sha2_password. To enable MySQL 5.7 clients to
connect to 8.0 and higher servers using accounts that
authenticate with caching_sha2_password, the MySQL 5.7
client library and client programs now support the
caching_sha2_password client-side authentication plugin.
This improves MySQL 5.7 client connect-capability
compatibility with respect to MySQL 8.0 and higher
servers, despite the differences in default
authentication plugin. For more information, see Caching
SHA-2 Pluggable Authentication
(http://dev.mysql.com/doc/refman/5.7/en/caching-sha2-pluggable-authentication.html).

SQL Syntax Notes


* Explicit ASC or DESC qualifiers for GROUP BY clauses are
now deprecated and will be removed in a future MySQL
version.

Functionality Added or Changed


* Previously, for the --ssl-mode=VERIFY_IDENTITY or
--ssl-verify-server-cert option, the client checked
whether the host name that it used for connecting matched
the Common Name value in the certificate but not the
Subject Alternative Name value. Now, if the client uses
OpenSSL 1.0.2 or higher, the client checks whether the
host name matches either the Subject Alternative Name
value or the Common Name value in the server certificate.
Thanks to Dani=C3=ABl van Eeden for a patch on which this
change was based. (Bug #16211011, Bug #68052,
Bug #27511233, Bug #89578)

Bugs Fixed


* Important Change; Partitioning: After creating
partitioned InnoDB tables with very long names, the
table_name columns in the corresponding entries in the
mysql.innodb_index_stats and mysql.innodb_table_stats
system tables were truncated. To fix this issue, the
length of the table_name column in each of these tables
has been increased from 64 to 199 characters. In both
cases, this is now the same as the lengths of these
columns in MySQL 8.0.
When upgrading to this release, use mysql_upgrade to
effect these changes in your MySQL installation. In the
event that you fail to do this, MySQL generates the
warning Table mysql/innodb_table_stats has length
mismatch in the column name table_name. Please run
mysql_upgrade in the error log.
Note
Some platforms, such as Microsoft Windows, may restrict
path lengths (MAX_PATH) to a maximum of 260, which can
cause creation of partitioned tables with long names to
fail. You can avoid this problem on Windows systems by
enabling NTFS long path names; see your system
documentation for information on how to do this.
(Bug #86926, Bug #26390736)

* InnoDB: The ngram full-text search parser permitted comma
and period characters to be tokenized as words, which
caused an inconsistency between boolean and natural
language mode search results. Comma and period characters
are no longer tokenized. (Bug #27847697)

* InnoDB: An I/O error returned by an fsync() operation is
now treated as a hard error. (Bug #27805553, Bug #90296)

* InnoDB: A schema mismatch error reported during an import
tablespace operation failed to print mismatched table
flags in a readable format. (Bug #27542720)

* InnoDB: A DDL operation failed to wait for a FULLTEXT
index optimization operation to finish. (Bug #27326796)
References: This issue is a regression of: Bug #24938374.

* InnoDB: An unnecessary check for read-only transactions
was removed from the trx_set_rw_mode() function. Thanks
to Sandeep Sethia for the patch. (Bug #27211287, Bug
#88739)

* InnoDB: A DDL operation that added a foreign key
constraint raised an assertion when it accessed a stale
memory object that belonged to the parent table. (Bug
#27208858)

* InnoDB: A DDL operation on a table with a FULLTEXT index
during full-text index cache synchronization caused an
assertion failure. (Bug #27082268, Bug #27095935)

* InnoDB: A failing assertion occurred after initiating a
memcached get operation. (Bug #26876594)

* InnoDB: A corrupt index ID encountered during a foreign
key check raised an assertion. (Bug #26654685)

* InnoDB: An internal deadlock during a DDL operation
resulted in a long semaphore wait followed by a server
exit. (Bug #26225783)

* InnoDB: A DDL operation encountered a serious error due
to an invalid lock upgrade. (Bug #26225783)

* InnoDB: On a Windows 64-bit system, invalid buffer pool
configuration values caused the server to exit on
startup. (Bug #26100239, Bug #86370)

* Partitioning: For a partitioned table, partition update
time could be incorrect after rebuilding the table or
restarting the server. (Bug #27073100)

* Partitioning: An extraneous row lock was imposed by an
update to a partitioned InnoDB table. (Bug #87253, Bug
#26553164)

* Replication: The log messages generated when a member
fails to join the group have been improved, for example
when group_replication_group_name on the member joining
the group does not match the seed's
group_replication_group_name this is now described in the
log message. (Bug #27628695)

* Replication: The
ER_GRP_RPL_SQL_SERVICE_FAILED_TO_RUN_SQL_QUERY error was
being logged incorrectly. (Bug #27590534)

* Replication: The use of replication filters or binary log
filters can cause issues when they are applied to tables
that are updated with XA transactions. Filtering of
tables could cause an XA transaction to be empty on a
replication slave, and empty XA transactions are not
supported. Also, with the settings
master_info_repository=TABLE and
relay_log_info_repository=TABLE on a replication slave,
which became the defaults in MySQL 8.0, the internal
state of the data engine transaction is changed following
a filtered XA transaction, and can become inconsistent
with the replication transaction context state.
Due to these issues, the use of replication filters or
binary log filters in combination with XA transactions is
not supported. This fix adds the new error
ER_XA_REPLICATION_FILTERS, which is logged whenever an XA
transaction is impacted by a replication filter, whether
or not the transaction was empty as a result. If the
transaction is not empty, the replication slave is able
to continue running, but you should take steps to
discontinue the use of replication filters with XA
transactions in order to avoid potential issues. If the
transaction is empty, the replication slave stops. In
that event, the replication slave might be in an
undetermined state in which the consistency of the
replication process might be compromised. In particular,
the gtid_executed set on a slave of the slave might be
inconsistent with that on the master. To resolve this
situation, isolate the master and stop all replication,
then check GTID consistency across the replication
topology. Undo the XA transaction that generated the
error message, then restart replication. (Bug #27442477)

* Replication: When a transaction larger than the binary
log transaction cache size (binlog_cache_size) was
flushed to a temporary file during processing, and the
flush failed due to a lack of space in the temporary
directory, the flush error was not handled correctly. No
message was written to the error log, and the binary log
cache was not cleared after the transaction was rolled
back. Now, in this situation, the server takes an
appropriate action based on the binlog_error_action
setting (shut down the server or halt logging), and
writes a message to the error log. When the transaction
is rolled back, the server checks for flush errors and
clears the binary log cache if any occurred. (Bug
#27399620, Bug #89272)

* Replication: When GTIDs are in use for replication,
replicated transactions that are filtered out on the
slave are persisted. If binary logging is enabled on the
slave, the filtered-out transaction is written to the
binary log as a Gtid_log_event followed by an empty
transaction containing only BEGIN and COMMIT statements.
If binary logging is disabled, the GTID of the
filtered-out transaction is written to the
mysql.gtid_executed table. This process ensures that
there are no gaps in the set of executed GTIDs, and that
the filtered-out transactions are not retrieved again if
the slave reconnects to the master. Previously, this
process was not done for CREATE DATABASE, ALTER DATABASE,
and DROP DATABASE statements, but it is now carried out
for those statements as well as for others. (Bug
#27308751, Bug #88891)

* Replication: On a multithreaded slave, when a STOP SLAVE
statement is executed on the slave, followed by a START
SLAVE statement, the error log can report a different
position in the binary log for the slave SQL thread when
exiting, compared to the position reported for the slave
SQL thread at the subsequent initialization.
For a multithreaded slave, the position reported for the
SQL thread on exit is a low water mark, up to which the
replication stream is consistent and has no gaps.
Transactions appearing before the position are guaranteed
to have committed, but transactions after the position
may have committed or not. However, this low water mark
was being reported before the process to stop the worker
threads was actually carried out, and the low water mark
was subsequently updated by a checkpoint routine during
that process. The timing of the log message has now been
changed so that the final low water mark is reported as
the position for the SQL thread on exit. (Bug #27300658)

* Replication: In certain situations, such as during
distributed recovery procedure, the certification info
garbage collection was purging more data than it should,
resulting in conflicts not being detected. The garbage
collection procedure has been improved to take this case
in consideration. (Bug #89938, Bug #27652526)

* Replication: When the group_replication_applier channel's
applier thread encountered an error, the master_log_name
and end_log_pos in the error message were incorrect. In
Group Replication, the events of a transaction are
replicated before they are written to the binary log of
the member where the transaction originated. The result
is that the final master_log_name and the end_log_pos of
those events are unknown at the time they are applied on
the replica by group_replication_applier channel's
applier thread. To avoid confusion, now any such error
messages encountered by a group_replication_applier
channel do not contain the binary log name and the binary
log position. (Bug #89146, Bug #27368735)

* A heap overflow vulnerability in the MySQL client library
was fixed. (Bug #27980823)

* For generated columns that used the INTERVAL() function,
incorrect behavior could occur. (Bug #27881102)

* The exec_in_background command for mysqltest is now
available in MySQL 5.7. (Bug #27858055)

* An unencrypted connection could result from a client
connection attempt specifying that an encrypted
connection was required, if the server was not configured
to support SSL. (Bug #27759871)

* A BETWEEN clause comparing negative values could lead to
erroneous results. (Bug #27691347)

* Audit log filter rules did not permit class names to be
specified as an array of strings. That is now possible.
Example:
{
"filter": {
"class": [
{ "name": [ "connection", "general", "table_access" ] }
]
}
}
(Bug #27628325)


* On Windows, if the Visual C++ Redistributable for Visual
Studio had been removed, MySQL uninstallation using the
MSI installer failed. (Bug #27621546)

* The audit_log_read() user-defined function could
deadlock. In consequence of the fix for this issue,
audit_log_read() no longer uses a shared global buffer.
Each call allocates its own buffer, which exists for the
duration of the call. To control the buffer size, set the
audit_log_read_buffer_size system variable. Previously,
this variable existed only in global scope with a default
of 1MB. Now, the variable also exists in session scope,
has a smaller default of 32KB, and can be set at runtime.
Each client should set its session value of
audit_log_read_buffer_size appropriately for its use of
audit_log_read(). (Bug #27545962)

* Within stored procedures, it was not possible to write a
condition handler to catch foreign key failures if the
table involved used the FEDERATED storage engine. (Bug
#27509959)

* With the NO_ENGINE_SUBSTITUTION SQL mode disabled, an
error (rather than substitution) occurred for CREATE
TABLE and ALTER TABLE if the desired engine was disabled
using the disabled_storage_engines system variable. (Bug
#27502530)

* If MySQL Enterprise Firewall was configured with a large
number of rules, server shutdown could take a long time.
(Bug #27492122)

* A memory leak in the pfs-t unit test was fixed. Thanks to
Yura Sorokin for the patch. (Bug #27440735, Bug #89384)

* With automatic_sp_privileges enabled, the EXECUTE and
ALTER ROUTINE privileges were not correctly granted to
routine creators. (Bug #27407480)

* Some queries that used ordering could access an
uninitialized column during optimization and cause a
server exit. (Bug #27389294)

* For debug builds, an assertion was raised (rather than an
error) for ALTER TABLE for an ARCHIVE table with a
GEOMETRY NOT NULL column containing empty strings. (Bug
#27330634, Bug #89088)

* If system tables could not be read or initialized, the
server wrote an incomplete error message. Thanks to
Dani=C3=ABl van Eeden for a patch related to the fix. (Bug
#27302337, Bug #89001)

* The keyring_okv plugin did not always fail over to the
standby OKV server when the primary server was
unavailable. (Bug #27244099)

* The Performance Schema could attempt to access invalid
SOURCE column values. (Bug #27231036)

* Mishandling of internal privilege structures could cause
a server exit. (Bug #27230925)

* The UNION of a user-defined variable and a DECIMAL column
produced an incorrect result when using a UTF8 character
set. (Bug #27197235)

* Setting max_execution_time sometimes had no effect when
used with full-text search. (Bug #27155294)

* For attempts to increase the length of a VARCHAR column
of an InnoDB table using ALTER TABLE with the INPLACE
algorithm, the attempt failed if the column was indexed.
If an index size exceeded the InnoDB limit of 767 bytes
for COMPACT or REDUNDANT row format, CREATE TABLE and
ALTER TABLE did not report an error (in strict SQL mode)
or a warning (in nonstrict mode). (Bug #26848813)

* In MySQL 5.7.19, the mysql.gtid_executed table was
excluded from dumps. This table is no longer excluded but
its data is not dumped. (Bug #26643180, Bug #87455)
References: This issue is a regression of: Bug #82848,
Bug #24590891.

* The slave_rows_search_algorithms system variable controls
how rows are searched for matches when preparing batches
of rows for row-based logging and replication. Specifying
INDEX_SCAN as one of the search algorithms performs an
index scan if an index is present. In the situation where
a different primary key is used on the master and the
slave, and a unique key is present on the slave, a bug in
the code meant that the index scan was not being
performed as it should be, and a slower table scan was
being performed instead. The issue has now been corrected
so that an index scan is used. (Bug #26450129, Bug
#81500)

* Certain cases of subquery materialization could cause a
server exit. These queries now produce an error
suggesting that materialization be disabled. (Bug
#26402045)

* mysqldump exited abnormally for large --where option
values. (Bug #26171967, Bug #86496, Bug #27510150)

* For MyISAM tables, particular sequences of INSERT and
DELETE statements could cause table corruption. (Bug
#25541037)

* The SHOW CREATE USER statement requires the SELECT
privilege for the mysql database, except to see
information for the current user. In addition, for the
current user, the statement requires the SELECT privilege
for the mysql.user system table for display of the
password hash in the IDENTIFIED AS clause; otherwise, the
hash displays as <secret>. (Bug #24911117)

* CREATE FUNCTION produced an error if there was no default
database and the function body called another function.
(Bug #24357244, Bug #82350)

* For debug builds, a SELECT statement executed within a
stored program could raise an assertion if derived table
resolution failed. (Bug #23221336)

* If mysqldump or mysqlpump were used to dump binary data
without the --hex-blob option, reloading the dump file
could produce spurious warnings (values were inserted
correctly regardless of the warnings). Such values are
now written preceded by the _binary introducer to silence
the warnings. (Bug #22601255, Bug #80150)

On Behalf of MySQL/ORACLE RE Team
Gipson Pulla

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