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MySQL Community Server 5.7.33 has been released
Posted by: Gipson Pulla
Date: January 18, 2021 07:41AM

Dear MySQL users,

MySQL Server 5.7.33, a new version of the popular Open Source
Database Management System, has been released. MySQL 5.7.33 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 5.7.33 on new servers, please see
the MySQL installation documentation at

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

MySQL Server 5.7.33 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 5.7.33 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/

5.7.33 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 5.7.32. It may also be viewed
online at

  http://dev.mysql.com/doc/relnotes/mysql/5.7/en/news-5-7-33.html

Enjoy!

Changes in MySQL 5.7.33 (2021-01-18, General Availability)

Optimizer Notes


     * MySQL attempts to use an ordered index for any ORDER BY
       or GROUP BY query that has a LIMIT clause, overriding any
       other choices made by the optimizer, whenever it
       determines that this would result in faster execution.
       Because the algorithm for making this determination makes
       certain assumptions about data distribution and other
       conditions, it may not always be completely correct, and
       it is possible in some cases that choosing a different
       optimization for such queries can provide better
       performance. To handle such occurrences, it is now
       possible to disable this optimization by setting the
       optimizer_switch system variable's prefer_ordering_index
       flag to off.
       For more information about this flag and examples of its
       use, see Switchable Optimizations
https://dev.mysql.com/doc/refman/5.7/en/switchable-optimizations.html
       and LIMIT Query Optimization
https://dev.mysql.com/doc/refman/5.7/en/limit-optimization.html
       Our thanks to Jeremy Cole for the contribution. (Bug
       #31686878)
       References: See also: Bug #97001, Bug #30348211.

Security Notes


     * The linked OpenSSL library for MySQL Server has been
       updated to version 1.1.1i. Issues fixed in the new
       OpenSSL version are described at
       https://www.openssl.org/news/cl111.txt and
       https://www.openssl.org/news/vulnerabilities.html. (Bug
       #32260610)

Functionality Added or Changed


     * When invoked with the --all-databases option, mysqldump
       now dumps the mysql database first, so that when the dump
       file is reloaded, any accounts named in the DEFINER
       clause of other objects will already have been created.
       (Bug #32141046)

Bugs Fixed


     * InnoDB: The full-text search synchronization thread
       attempted to read a previously-freed word from the index
       cache. (Bug #31310404)

     * InnoDB: Calls to numa_all_nodes_ptr were replaced by the
       numa_get_mems_allowed() function. Thanks to Daniel Black
       for the contribution. (Bug #24693086, Bug #83044)

     * Replication: When the system variable
       transaction_write_set_extraction=XXHASH64 is set, which
       is the default in MySQL 8.0 and a requirement for Group
       Replication, the collection of writes for a transaction
       previously had no upper size limit. Now, for standard
       source to replica replication, the numeric limit on write
       sets specified by
       binlog_transaction_dependency_history_size is applied,
       after which the write set information is discarded but
       the transaction continues to execute. Because the write
       set information is then unavailable for the dependency
       calculation, the transaction is marked as non-concurrent,
       and is processed sequentially on the replica. For Group
       Replication, the process of extracting the writes from a
       transaction is required for conflict detection and
       certification on all group members, so the write set
       information cannot be discarded if the transaction is to
       complete. The byte limit set by
       group_replication_transaction_size_limit is applied
       instead of the numeric limit, and if the limit is
       exceeded, the transaction fails to execute. (Bug
       #32019842)

     * Replication: On a multi-threaded replica where the commit
       order is preserved, worker threads must wait for all
       transactions that occur earlier in the relay log to
       commit before committing their own transactions. If a
       deadlock occurs because a thread waiting to commit a
       transaction later in the commit order has locked rows
       needed by a transaction earlier in the commit order, a
       deadlock detection algorithm signals the waiting thread
       to roll back its transaction. Previously, if transaction
       retries were not available, the worker thread that rolled
       back its transaction would exit immediately without
       signalling other worker threads in the commit order,
       which could stall replication. A worker thread in this
       situation now waits for its turn to call the rollback
       function, which means it signals the other threads
       correctly. (Bug #26883680, Bug #87796)

     * Microsoft Windows: On Windows, running the MySQL server
       as a service caused shared-memory connections to fail.
       (Bug #32009251)

     * The server did not handle all cases of the
       WHERE_CONDITION optimization correctly. (Bug #31905199)

     * For the engines which support primary key extension, when
       the total key length exceeded MAX_KEY_LENGTH or the
       number of key parts exceeded MAX_REF_PARTS, key parts of
       primary keys which did not fit within these limits were
       not added to the secondary key, but key parts of primary
       keys were unconditionally marked as part of secondary
       keys.
       This led to a situation in which the secondary key was
       treated as a covering index, which meant sometimes the
       wrong access method was chosen.
       This is fixed by modifying the way in which key parts of
       primary keys are added to secondary keys so that those
       which do not fit within which do not fit within the
       limits mentioned previously mentioned are cleared. (Bug
       #31617858)

     * Privileges for some INFORMATION_SCHEMA tables were
       checked incorrectly. (Bug #31553323)

     * In certain cases, the server did not handle
       multiply-nested subqueries correctly. (Bug #31472704)

     * Certain accounts could cause server startup failure if
       the --skip-name-resolve option was enabled. (Bug
       #31018510)

     * Client programs could unexpectedly exit if communication
       packets contained bad data. (Bug #30890850)

     * A buffer overflow in the client library was fixed. (Bug
       #30885987)

     * mysql_config_editor incorrectly treated # in password
       values as a comment character. (Bug #29861961, Bug
       #95597)

On Behalf of MySQL/ORACLE RE Team
Gipson Pulla



Edited 1 time(s). Last edit at 01/18/2021 07:42AM by Gipson Pulla.

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