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MySQL Community Server 8.0.4-rc has been released (part 1/3)

[Due to size limitations, the announcement is split in 3. This is part 1.] 

MySQL Server 8.0.4-rc (Release Candidate) is a new version of the world's
most popular open source database. This is the second release
candidate of MySQL 8.0.


As with any other pre-production release, caution should be taken when
installing on production level systems or systems with critical data.

Note that 8.0.4-rc includes all features in MySQL 5.7.

For information on installing MySQL 8.0.4-rc on new servers, please see
the MySQL installation documentation at


MySQL Server 8.0.4-rc is available in source and binary form for a number of
platforms from the "Development Releases" selection of our download
pages at


MySQL Server 8.0.4-rc is also available from our repository for Linux
platforms, go here for details:


We welcome and appreciate your feedback, bug reports, bug fixes,
patches, etc.:


The following link lists the changes in the MySQL 8.0 since
the release of MySQL 8.0.3. It may also be viewed
online at



Changes in MySQL 8.0.4 (2018-01-23, Release Candidate)


   This is a milestone release, for use at your own risk.
   Upgrades between milestone releases (or from a milestone
   release to a GA release) are not supported. Significant
   development changes take place in milestone releases and you
   may encounter compatibility issues, such as data format
   changes that require attention in addition to the usual
   procedure of running mysql_upgrade. For example, you may find
   it necessary to dump your data with mysqldump before the
   upgrade and reload it afterward. (Making a backup before the
   upgrade is a prudent precaution in any case.)

   Beginning with MySQL 8.0.4, macOS 10.13 is a supported

   Also beginning with MySQL 8.0.4, Ubuntu 14.04 and Debian 8 are no
   longer supported platforms for MySQL 8.0.
     * Compilation Notes

     * Component Notes

     * Configuration Notes

     * Deprecation and Removal Notes

     * Function Notes

     * InnoDB Notes

     * Installation Notes

     * Logging Notes

     * Packaging Notes

     * Performance Schema Notes

     * Security Notes

     * Server Administration

     * Spatial Data Support

     * Test Suite Notes

     * X Plugin Notes

     * Functionality Added or Changed

     * Bugs Fixed

   Compilation Notes

     * Linux: Binary packages on Linux platforms now are built
       using GCC 6. The optimization level has changed from -O3
       to -O2.

     * macOS; Microsoft Windows: For compiling MySQL from
       source, the -DWITH_SSL=system CMake option now works on
       Windows and macOS. (Bug #26907731, Bug #87938)

     * On platforms for which the GNU gold linker is used,
       removal of unused functions is now enabled, reducing the
       size of binaries. (Bug #26612067, Bug #87372)

     * #include directives in source files were rewritten and
       reorganized to be unambiguous. (Bug #26597243, Bug
       #87358, Bug #26897738)

     * The BUILD directory containing compilation scripts is no
       longer maintained and has been removed from MySQL source
       trees. (Bug #26576219, Bug #87323)

     * The minimum version of the Boost library for server
       builds is now 1.65.0. (Bug #26574924, Bug #87317)

     * MySQL can now be linked against OpenSSL 1.1 on Unix and
       Unix-like systems. (Bug #25094892, Bug #83814)

     * Work was done to clean up the source code base,
       including: Removing unneeded CMake checks; removing
       unused macros from source files; reorganizing header
       files to reduce the number of dependencies and make them
       more modular, removing function declarations without
       definitions, replacing locally written functions with
       equivalent functions from industry-standard libraries.

   Component Notes

     * The validate_password plugin has been reimplemented to
       use the server component infrastructure. To install and
       uninstall the validate_password component, use these
INSTALL COMPONENT 'file://component_validate_password';
UNINSTALL COMPONENT 'file://component_validate_password';

       INSTALL PLUGIN and UNINSTALL PLUGIN still work to install
       and uninstall the validate_password plugin as before, but
       generate warnings. The plugin form of validate_password
       is deprecated and will be removed in a future version of
       MySQL. MySQL installations that use the plugin should
       transition to the component instead. See Transitioning to
       the Password Validation Component
       A usage difference between the component and plugin
       implementations of validate_password is that, whereas the
       plugin exposes system and status variables with names
       that begin with validate_password_, the component uses
       the convention of exposing variables with names that
       begin with the component name and a period. For example,
       the plugin exposes the validate_password_policy system
       variable and
       validate_password_dictionary_file_words_count status
       variable, whereas the corresponding variables exposed by
       the component are validate_password.policy and
       validate_password.dictionary_file_words_count. The plugin
       variables, like the plugin itself, are deprecated and
       will be removed in a future version of MySQL.

   Configuration Notes

     * Replication: When calculating the binary log expiration
       period, any value that you specify for the deprecated
       expire_logs_days system variable is now ignored if
       binlog_expire_logs_seconds is set, and only the value of
       binlog_expire_logs_seconds is used. Previously, the
       effects of binlog_expire_logs_seconds and
       expire_logs_days were cumulative.
       If you set a value for both system variables at startup,
       a warning message is issued stating that the value of
       expire_logs_days is ignored. You cannot set or change the
       value of one option dynamically while the other is set,
       and an error message is issued in this situation.
       The default binary log expiration period of 30 days (as
       changed in MySQL 8.0.2) applies if neither
       binlog_expire_logs_seconds nor expire_logs_days has a
       value set at startup. If a value for either
       binlog_expire_logs_seconds or expire_logs_days is set at
       startup, this value overrides the default binary log
       expiration period. To disable automatic purging of the
       binary log, you must set both binlog_expire_logs_seconds
       and expire_logs_days explicitly to 0 at startup. (Bug
       #26274274, Bug #86698)

     * For RHEL, SLES, and Fedora RPMs, the default plugin
       directory for debug builds has been changed from
       /usr/lib64/mysql/plugin to /usr/lib64/mysql/plugin/debug.
       (Bug #27072155, Bug #88363)

     * The table_open_cache system variable default variable has
       been increased from 2000 to 4000. This additionally
       changes the default for the autosized
       table_definition_cache system variable from 1400 to 2000.

     * The optimizer_trace_max_mem_size system variable default
       value was changed from 16KB to 1MB to lessen the
       likelihood of optimizer trace truncation.

     * The log_error_verbosity system variable default value was
       changed from 3 (Errors, Warnings, Notes) to 2 (Errors,
       Warnings) to make mysqld error logging less verbose by

   Deprecation and Removal Notes

     * InnoDB: The innodb_undo_tablespaces configuration option
       is deprecated and will be removed in a future release.

     * Replication: The group_replication_primary_member status
       variable has been deprecated and will be removed in a
       future version.

     * Replication: The
       group_replication_allow_local_disjoint_gtids_join system
       variable has been removed.

     * When the libmysqld embedded server library was removed in
       MySQL 8.0.1, the following mysql_options() options used
       only for libmysqld were not removed. They have now been

       (Bug #26712418)

     * Generated columns no longer permit deprecated functions
       in the generation expression, to avoid problems when
       MySQL is upgraded to a version in which the deprecated
       functions have been removed. (Bug #26279884, Bug #86712)

   Function Notes

     * Incompatible Change: Previously, MySQL used the Henry
       Spencer regular expression library to support regular
       expression operators (REGEXP, RLIKE). Regular expression
       support has been reimplemented using International
       Components for Unicode (ICU), which provides full Unicode
       support and is multibyte safe. The REGEXP_LIKE() function
       performs regular expression matching in the manner of the
       REGEXP and RLIKE operators, which now are synonyms for
       that function. In addition, the REGEXP_INSTR(),
       REGEXP_REPLACE(), and REGEXP_SUBSTR() functions are
       available to find match positions and perform substring
       substitution and extraction, respectively. The
       regexp_stack_limit and regexp_time_limit system variables
       provide control over resource consumption by the match
       MySQL source distributions bundle the ICU library, and
       the WITH_ICU CMake option controls whether to compile
       with the bundled or system ICU library. The ICU_VERSION()
       function returns the ICU library version.
       For more information, see Regular Expressions
       (http://dev.mysql.com/doc/refman/8.0/en/regexp.html). For
       information about ways in which applications that use
       regular expressions may be affected by the implementation
       change, see Regular Expression Compatibility

     * Two new SQL functions are available to provide digest
       information about SQL statements. Given an SQL statement
       as a string, STATEMENT_DIGEST() returns the statement
       digest hash value, and STATEMENT_DIGEST_TEXT() returns
       the normalized statement digest. See Encryption and
       Compression Functions

   InnoDB Notes

     * The restriction enacted in MySQL 8.0.3 against renaming
       of columns in a parent foreign key has been lifted. (Bug
       #26659110, Bug #87490, Bug #25722221)
       References: See also: Bug #26334071.

   Installation Notes

     * For platforms that use systemd (see Managing MySQL Server
       with systemd
       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):

       (Bug #26595288, Bug #87287)

   Logging Notes

     * A new error log filter component, log_filter_dragnet,
       enables control over events written to the error log,
       based on user-defined rules specified as the value of the
       dragnet.log_error_filter_rules system variable. This new
       filtering capability is more flexible than is achievable
       using the built-in log_filter_internal filter component
       and log_error_verbosity system variable. For more
       information, see Error Log Filtering

     * Messages written to the error log by the
       log_sink_internal log writer component now contain an
       error-ID indicator. This ID has a format of [error_id].
       It follows the severity indicator and precedes the
       message text. For more information, see Error Log Message

     * When the log_error_verbosity system variable for error
       logging is set to filter out notes and warnings, selected
       important messages about non-error situations are now
       printed to error logs as system messages. These messages
       were previously handled and labeled as errors so that
       they were logged when log_error_verbosity=1 was set. The
       labeling function has now been decoupled from the
       handling function for these messages, so that the
       messages can be given an appropriate label.
       System messages now have the label "System" in the MySQL
       error log. Other log writers that support custom labels
       might also use this convention. In logs that do not
       support custom labels, system messages are printed with
       the label used for the information level of severity.
       However, they are included even if the
       log_error_verbosity setting would normally exclude
       messages at this level.
       If your system has additional configuration to discard
       messages labeled as information level, or to redirect
       them to a different destination from messages labeled as
       errors, system messages do not override this behavior. If
       the log writer involved does not use the "System" label,
       system messages will now be discarded or redirected along
       with other messages labeled as information level.
       The messages that are now printed with the "System" label
       where supported include startup and shutdown messages,
       and some significant changes to settings, as follows:

          + ER_STARTING_AS

          + ER_STARTUP












   Packaging Notes

     * All MySQL binary distributions now are linked against
       OpenSSL, including Community distributions, which
       previously were linked against yaSSL. In addition,
       OpenSSL is linked dynamically rather than statically,
       which enables substitution of alternative SSL libraries
       for use with MySQL if desired. For some platforms, binary
       distributions bundle OpenSSL libraries to ensure library

          + Windows: Distributions bundle libeay32.dll and
            ssleay32.dll, which are installed in the same
            directory as MySQL binaries. Other libraries can be
            used by replacing those library files with
            alternatives, or by using some other
            library-selection method supported on Windows. (See

          + macOS: Distributions bundle libssl.dylib and
            libcrypto.dylib. MySQL binaries are linked to expect
            the libraries in the same directory, and symbolic
            links there point to the actual library locations.

          + Linux (for generic compressed tar file distributions
            only): Distributions bundle libssl.so and
            libcrypt.so,which are installed in the same
            directory as the libmysqlclient.so client library.
       (Bug #26272084, Bug #26134893, Bug #26927607, Bug #87996)

   Performance Schema Notes

     * The Performance Schema now uses SHA-256 hashes for
       statement digests rather than MD5 hashes. To accommodate
       the increased storage required for SHA-256 values, DIGEST
       columns in Performance Schema tables are widened from
       VARCHAR(32) to VARCHAR(64). (Bug #26727443)

     * The Performance Schema setup_timers table has been
       removed, as has the TICK row in the performance_timers

   Security Notes

     * Incompatible Change: Passwords are now restricted to a
       maximum of 256 characters for the caching_sha2_password
       and sha256_password authentication plugins, and for the
       PASSWORD() function when old_passwords=2. Also, the
       number of password hashing rounds is capped to limit CPU
       time used. (Bug #27099029, Bug #27194270)

     * Incompatible Change: The caching_sha2_password and
       sha256_password authentication plugins provide more
       secure password encryption than the mysql_native_password
       plugin, and caching_sha2_password provides better
       performance than sha256_password. Due to these superior
       security and performance characteristics of
       caching_sha2_password, it is now the preferred
       authentication plugin, and is also the default
       authentication plugin rather than mysql_native_password.
       This change affects both the server and the
       libmysqlclient client library:

          + For the server, the default value of the
            default_authentication_plugin system variable
            changes from mysql_native_password to

          + The libmysqlclient library treats
            caching_sha2_password as the default authentication
            plugin rather than mysql_native_password.
       This change has the following implications:

          + The change affects only the authentication plugin
            used for creating new MySQL accounts. For accounts
            already existing in an upgraded installation, their
            authentication plugin remains unchanged.

          + Clients that use an account that authenticates with
            caching_sha2_password must use either a secure
            connection (made using TCP using TLS/SSL
            credentials, a Unix socket file, or shared memory),
            or an unencrypted connection that supports password
            exchange using an RSA key pair. This security
            requirement does not apply to
            mysql_native_passsword, so the switch to
            caching_sha2_password may require additional
            configuration (see Caching SHA-2 Pluggable
            However, client
            connections in MySQL 8.0 prefer use of TLS/SSL by
            default, so clients that already conform to that
            preference may need no additional configuration.

          + Because caching_sha2_password is also now the
            default authentication plugin in the libmysqlclient
            client library, authentication requires an extra
            round trip in the client/server protocol for
            connections from MySQL 8.0 clients to accounts that
            use mysql_native_password (the previous default
            authentication plugin), unless the client program is
            invoked with a --default-auth=mysql_native_password

          + Incompatibility: Clients and connectors that have
            not been updated to know about caching_sha2_password
            cannot connect to accounts that authenticate with
            caching_sha2_password because they do not recognize
            this plugin as valid. To work around this issue,
            relink clients against libmysqlclient from MySQL
            8.0.4 or higher, or obtain an updated connector that
            recognizes caching_sha2_password.

          + Incompatibility: Clients and connectors that have
            not been updated to know about caching_sha2_password
            may have trouble connecting to a MySQL 8.0 server
            configured with caching_sha2_password as the default
            authentication plugin, even to use accounts that do
            not authenticate with caching_sha2_password. This
            issue occurs because the server specifies the name
            of its default authentication plugin to clients. If
            a client or connector is based on a client/server
            protocol implementation that does not gracefully
            handle an unrecognized default authentication
            plugin, it may fail with an error.
       For more information about the more prominent role of
       caching_sha2_password, including discussion of potential
       compatibility issues and solutions, see
       caching_sha2_password as the Preferred Authentication
       Additionally, replication slaves are now able to connect
       to masters using RSA key pair-based password exchange.
       This RSA capability applies for accounts that
       authenticate with the caching_sha2_password or
       sha256_password authentication plugin. (Previously,
       slaves could authenticate with those plugins, but
       required a secure connection and could not use RSA
       password exchange.) The following changes enable use of
       this new slave RSA capability:

          + The CHANGE MASTER TO statement has clauses for
            specifying RSA public key information.

          + For Group Replication, the
            group_replication_recovery_public_key_path and
            group_replication_recovery_get_public_key system
            variables serve the same purpose.

          + The SHOW SLAVE STATUS statement and the Performance
            Schema replication_connection_configuration table
            display replication slave RSA public key
       More programs now support a --server-public-key-path
       option to enable specifying a client-side file containing
       the public key for RSA key pair-based password exchange,
       for accounts that authenticate with the
       caching_sha2_password or sha256_password authentication
       plugin: mysqladmin, mysqlbinlog, mysqlcheck, mysqldump,
       mysqlimport, mysqlpump, mysqlshow, mysqlslap,
       mysql_upgrade. Previously, only mysql and mysqltest
       supported --server-public-key-path. The
       --server-public-key-path option is an alternative to
       --get-server-public-key, and may be used when a
       client-side file is available that contains a copy of the
       RSA public key required by the server, rather than
       sending a request for the public key to the server.
       The new mysql_reset_server_public_key() C API function
       clears any cached copy of the server RSA public key from
       the client library. See mysql_reset_server_public_key()
       The new caching_sha2_password_auto_generate_rsa_keys
       system variable enables automatic RSA private/public
       key-pair file generation, similar to the
       sha256_password_auto_generate_rsa_keys system variable.
       See Automatic SSL and RSA File Generation
       The new Caching_sha2_password_rsa_public_key status
       variable exposes the public key used by the
       caching_sha2_password authentication plugin for RSA key
       pair-based password exchange. (Bug #26751594)

     * The linked OpenSSL library for MySQL Server has been
       updated to version 1.0.2n. Issues fixed in the new
       OpenSSL version are described at
       http://www.openssl.org/news/vulnerabilities.html. (Bug
       #27212666, Bug #27236394)

     * Certificates automatically generated by mysqld and
       mysql_ssl_rsa_setup now use X509 v3 rather than v1. (Bug

     * MySQL now supports key migration between underlying
       keyring keystores. This enables DBAs to switch a MySQL
       installation from one keyring plugin to another. See
       Migrating Keys Between Keyring Keystores

   Server Administration

     * A new RESTART SQL statement is available that enables
       restarting a MySQL server instance from within a client
       session. This feature is available for platforms on which
       a monitoring process is able to detect a server shutdown
       performed for restart purposes: Windows (mysqld started
       as a Windows service or standalone), and Unix and
       Unix-like systems that use systemd or mysqld_safe to
       manage mysqld. See RESTART Syntax

   Spatial Data Support

     * Incompatible Change: These spatial import functions now
       return an error for data in a geographic spatial
       reference system for which the coordinates are outside
       the legal range of values: ST_GeomCollFromText(),
       ST_GeomCollFromTxt(), ST_GeomCollFromWKB(),
       ST_GeometryCollectionFromWKB(), ST_GeometryFromText(),
       ST_GeometryFromWKB(), ST_GeomFromGeoJSON(),
       ST_GeomFromText(), ST_GeomFromWKB(), ST_LineFromText(),
       ST_LineFromWKB(), ST_LineStringFromText(),
       ST_LineStringFromWKB(), ST_MLineFromText(),
       ST_MLineFromWKB(), ST_MPointFromText(),
       ST_MPointFromWKB(), ST_MPolyFromText(),
       ST_MPolyFromWKB(), ST_MultiLineStringFromText(),
       ST_MultiLineStringFromWKB(), ST_MultiPointFromText(),
       ST_MultiPointFromWKB(), ST_MultiPolygonFromText(),
       ST_MultiPolygonFromWKB(), ST_PointFromText(),
       ST_PointFromWKB(), ST_PolyFromText(), ST_PolyFromWKB(),
       ST_PolygonFromText(), ST_PolygonFromWKB().
       (ST_LatFromGeoHash(), ST_LongFromGeoHash(), and
       ST_PointFromGeoHash() do not have this behavior because
       they cannot represent out-of-range values.)
       ST_GeomFromGeoJSON() also now returns an error if a crs
       member that specifies an SRID different from the
       top-level object SRID is found at a lower level of the
       GeoJSON document.
       If spatial data contains SRID values that refer to a
       geographic spatial reference system and the data
       coordinates are out of range, existing queries using
       these functions will return different results, compared
       to previous MySQL versions.
       (Bug #26941370, Bug #88031)

     * Incompatible Change: Previously, these spatial functions
       ignored the spatial reference system (SRS) for geometry
       arguments and computed results on a Cartesian plane. They
       now support computations for geometry arguments that
       specify a geographic SRS: ST_Distance_Sphere(),
       ST_IsSimple(), ST_IsValid(), ST_Length().
       Previously, these spatial functions ignored the SRS for
       any geometry arguments and computed results on a
       Cartesian plane. They now produce an error when invoked
       with geometry arguments that specify a geographic SRS:
       ST_Area(), ST_Buffer(), ST_Centroid(), ST_ConvexHull(),
       ST_Difference(), ST_Envelope(), ST_Intersection(),
       ST_IsClosed(), ST_MakeEnvelope(), ST_Simplify(),
       ST_SymDifference(), ST_Union(), ST_Validate().
       Previously, these spatial functions permitted geometry
       arguments with an undefined SRS. They now produce an
       error when invoked with geometry arguments that have an
       undefined SRS: ST_Dimension(), ST_Distance_Sphere(),
       ST_EndPoint(), ST_ExteriorRing(), ST_GeometryN(),
       ST_GeometryType(), ST_InteriorRingN(), ST_IsEmpty(),
       ST_IsSimple(), ST_IsValid(), ST_Length(),
       ST_NumGeometries(), ST_NumInteriorRing(),
       ST_NumInteriorRings(), ST_NumPoints(), ST_PointN(),
       ST_StartPoint(), ST_SwapXY(), ST_X(), ST_Y().
       Previously, the ST_GeoHash() spatial function accepted
       points with any SRID. ST_GeoHash() now accepts only
       points with SRID 0 or 4326.
       If spatial data contains geometry values that now are
       interpreted differently by the functions just listed,
       existing queries using these functions will return
       different results, compared to previous MySQL versions.

     * Incompatible Change: For the following spatial functions
       that take an SRID argument, they now return an error if
       the SRID does not exist: ST_GeomCollFromText(),
       ST_GeomCollFromTxt(), ST_GeomCollFromWKB(),
       ST_GeometryCollectionFromWKB(), ST_GeometryFromText(),
       ST_GeometryFromWKB(), ST_GeomFromGeoJSON(),
       ST_GeomFromText(), ST_GeomFromWKB(), ST_LineFromText(),
       ST_LineFromWKB(), ST_LineStringFromText(),
       ST_LineStringFromWKB(), ST_MLineFromText(),
       ST_MLineFromWKB(), ST_MPointFromText(),
       ST_MPointFromWKB(), ST_MPolyFromText(),
       ST_MPolyFromWKB(), ST_MultiLineStringFromText(),
       ST_MultiLineStringFromWKB(), ST_MultiPointFromText(),
       ST_MultiPointFromWKB(), ST_MultiPolygonFromText(),
       ST_MultiPolygonFromWKB(), ST_PointFromGeoHash(),
       ST_PointFromText(), ST_PointFromWKB(), ST_PolyFromText(),
       ST_PolyFromWKB(), ST_PolygonFromText(),
       ST_PolygonFromWKB(). (ST_SRID() already had this
       If spatial data contains SRID values that refer to a
       nonexistent spatial reference system, existing queries
       using these functions will return different results,
       compared to previous MySQL versions.

     * The EPSG Dataset containing spatial reference system data
       for spatial calculations has been upgraded from version
       9.0 to 9.2. (Bug #26711258, Bug #87564, Bug #26990896)

       DROP SPATIAL REFERENCE SYSTEM statements for creating and
       removing spatial reference system (SRS) definitions in
       the data dictionary. See CREATE SPATIAL REFERENCE SYSTEM
       With the implementation of these
       statements, direct access to the
       mysql.st_spatial_reference_systems data dictionary table
       using statements such as SELECT, INSERT, and UPDATE is
       not needed, and is no longer permitted. Read access to
       SRS definitions remains available through the

   Test Suite Notes

     * Documentation for the MySQL Test Suite is now maintained
       in the MySQL source tree using Doxygen (see
       The related Unix man pages that
       previously were produced from the old test suite manual
       are no longer updated and have gone out of date.
       Consequently, they are no longer included in MySQL
       distributions. (Bug #27021754)

     * The MySQL test suite now includes CRC32() tests. Thanks
       to Daniel Black for the patch. (Bug #26495791, Bug

   X Plugin Notes

     * X Plugin could incorrectly remove quotes from parameters
       that were passed to functions expecting JSON strings,
       causing an error. (Bug #26906519)

     * After an index was created on a collection, X Plugin
       would list the collection as a relational table, and no
       longer list it as a collection. (Bug #26906487)

     * X Protocol displayed the DATE type in the same way as the
       DATETIME type. The two data types are now treated
       differently. (Bug #26647488)

     * mysqlxtest did not display fractional seconds in DATETIME
       values correctly. (Bug #26638422)

     * X Plugin returned a column metadata field showing
       fractional digits for a JSON column, for which that
       information was irrelevant. The field is no longer
       returned. (Bug #26258481)

     * X Plugin handled user account lookup incorrectly if the
       IP address resolved to an empty host name. (Bug

     * X Plugin can now be configured to abort any authenticated
       connections which are considered idle. The following
       variables have been added:

          + --mysqlx-interactive-timeout

          + --mysqlx-read-timeout

          + --mysqlx-wait-timeout

          + --mysqlx-write-timeout

     * X Plugin now supports Caching SHA-2 Pluggable
       To enable the support, issue:
INSTALL PLUGIN mysqlx_cache_cleaner SONAME 'mysqlx.so';
       This plugin maintains the cache and removes all entries
       for accounts that were modified.
       References: See also: Bug #27213213, Bug #27042109.

   Functionality Added or Changed

     * InnoDB: Obsoleted InnoDB system tables that are no longer
       required after upgrading to MySQL 8.0.3 or later are now
       dropped after a successful upgrade. (Bug #26757171)

     * InnoDB: Support was added to automatically upgrade data
       dictionary table definitions when starting the MySQL
       server after upgrading MySQL binaries to a new version.
       At startup, the data dictionary version of the server is
       compared to the version information stored in the data
       dictionary to determine if data dictionary tables should
       be upgraded. If an upgrade is necessary and supported,
       the server creates data dictionary tables with updated
       definitions, copies persisted metadata to the new tables,
       atomically replaces the old tables with the new ones, and
       reinitializes the data dictionary. If an upgrade is not
       necessary, startup continues without updating the data
       dictionary tables.
       The mysqld --no-dd-upgrade option can be used to prevent
       automatic upgrade of data dictionary tables at startup.

     * InnoDB: Moving or restoring tablespace files to a new
       location while the server is offline is supported by the
       new --innodb-directories option, which defines
       directories to scan at startup for tablespace files. For
       more information, see Moving Tablespace Files While the
       Server is Offline
       With the introduction of the --innodb-directories
       feature, the location of file-per-table and general
       tablespace files created with an absolute path or in a
       location outside of the data directory should be added to
       the innodb_directories argument value. Otherwise, InnoDB
       is not able to locate these files during recovery. To
       view tablespace file locations, query the

       The CREATE TABLESPACE ... ADD DATAFILE statement now
       requires that a specified directory is known to InnoDB.
       Known directories include those implicitly and explicitly
       defined by the innodb_directories option.

     * InnoDB: InnoDB now supports partial fetch and update of
       large object (LOB) data stored in external fields outside
       of clustered index pages, including JSON documents
       updated using JSON_SET() and JSON_REPLACE(). Previously,
       LOB values could only be read or modified in full, and
       updates of JSON column values were done by completely
       removing the previous document and writing the new one in
       its place.
       Partial fetch and update uses an internal LOB index, or
       ZLOB index in the case of compressed LOB data, which is
       created and stored in one or more LOB pages when a row
       containing LOB data is inserted or updated. Thus, partial
       fetch and update of LOB data is supported for newly
       inserted rows, but existing rows containing LOB data must
       be updated to add partial fetch and update support. The
       addition of LOB index data increases the storage space
       required by LOB values by a small percentage.
       This feature adds the following InnoDB page types for
       storing uncompressed and compressed LOB data:









     * InnoDB: The storage engine private field of the
       mysql.tablespaces data dictionary table and page 0 of
       InnoDB tablespace files now store MySQL server version
       and tablespace version information. The MySQL server
       version is the version that created the tablespace, the
       version into which the tablespace was imported, or the
       version of the last major MySQL upgrade. The tablespace
       version tracks tablespace format changes. SERVER_VERSION
       and SPACE_VERSION fields were added to the
       access to this data.

     * Replication: Host names can now be specified as part of a
       whitelist for group replication connections, using the
       group_replication_ip_whitelist system variable. Host
       names support CIDR notation. Host names that resolve to
       IPv6 addresses are not supported.
       For host names, name resolution takes place only when a
       connection request is made by another server. A host name
       that cannot be resolved is not considered for whitelist
       validation, and a warning message is written to the error
       log. Forward-confirmed reverse DNS (FCrDNS) verification
       is carried out for resolved host names.
       Host names are inherently less secure than IP addresses
       in a whitelist. FCrDNS verification provides a good level
       of protection, but can be compromised by certain types of
       attack. Specify host names in your whitelist only when
       strictly necessary, and ensure that all components used
       for name resolution, such as DNS servers, are maintained
       under your control. You can also implement name
       resolution locally using the hosts file, to avoid the use
       of external components.

     * JSON: Added the JSON_TABLE() function, which accepts JSON
       data and returns it as a relational table whose columns
       are as specified. This virtual table can be accessed
       using standard SQL mechanisms
       This function has the syntax JSON_TABLE(expr, path
       COLUMNS column_list) [AS] alias), where expr is an
       expression that returns JSON data, path is a JSON path
       applied to the source, and column_list is a list of
       column definitions. Columns can be of the types FOR
       described in the following list:

          + FOR ORDINAL: The column is a counter, similar to an
            AUTO_INCREMENT column.

          + PATH: The column holds a scalar value using the
            specified JSON path. ON ERROR and ON EMPTY options
            are supported for handling illegal values (such as
            nonscalars) and empty values, respectively.

          + EXISTS PATH: The column value is 1 if a match exists
            for the specified JSON path, and 0 otherwise.

          + NESTED PATH: Nested objects or arrays in JSON data
            found in the given JSON path are flattened into a
            single row along with the JSON values from the
            parent object or array. The PATH keyword is
       Two simple examples are shown here:
mysql> SELECT *
    -> FROM
    ->   JSON_TABLE(
    ->     '[1, 3, 5, 7, 9]',
    ->     "$[*]" COLUMNS(rowid FOR ORDINALITY, col VARCHAR(50) PATH "
    ->   ) AS t1;
| rowid | col  |
|     1 | 1    |
|     2 | 3    |
|     3 | 5    |
|     4 | 7    |
|     5 | 9    |

mysql> SET @j = '[{"a": [{"x":"3"},{"y":"2"}]},
    '>   {"b": [{"x":"1"},{"y":"1"}]},
    '>   {"a": [{"x":"2"},{"y":"3"}]}]';

mysql> SELECT *
    ->         @j,
    ->         "$[*]"  COLUMNS(
    ->                   rowid FOR ORDINALITY,
    ->                   xa INT EXISTS PATH "$.a",
    ->                   xb INT EXISTS PATH "$.b",
    ->                   ja JSON PATH "$.a",
    ->                   jb JSON PATH "$.b"
    ->                 )
    ->       ) AS jts;
| rowid | xa   | xb   | ja                       | jb
|     1 |    1 |    0 | [{"x": "3"}, {"y": "2"}] | NULL
|     2 |    0 |    1 | NULL                     | [{"x": "1"}, {"y":
"1"}] |
|     3 |    1 |    0 | [{"x": "2"}, {"y": "3"}] | NULL

       The JSON source expression can be any expression that
       yields a valid JSON document, including a JSON literal, a
       table column, or a function call that returns JSON such
       as JSON_EXTRACT(t1, data, '$.post.comments'). For
       complete syntax and other information about this
       function, see JSON Table Functions

     * The -DWITH_ASAN_SCOPE CMake option enables the
       AddressSanitizer -fsanitize-address-use-after-scope Clang
       flag for use-after-scope detection. The default is off.
       To use this option, -DWITH_ASAN must also be enabled.
       (Bug #27095089)

     * Handling of empty JSON documents has been made more
       robust. (Bug #26787468, Bug #87734)

     * MySQL 8.0.3 imposed a restriction against ALTER TABLE
       RENAME on tables in a foreign key relationship if a LOCK
       TABLES was active. This restriction has been lifted. (Bug
       #26647340, Bug #87467)

     * If the server PID file is configured to be created in a
       world-writable location, the server now issues a warning
       suggesting use of a more secure location. (Bug #26585560)

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