[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.

http://dev.mysql.com/doc/mysql-development-cycle/en/development-milestone-releases.html

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

http://dev.mysql.com/doc/refman/8.0/en/installing.html

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

http://dev.mysql.com/downloads/mysql/

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

http://dev.mysql.com/downloads/repo/

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 8.0 since
the release of MySQL 8.0.3. It may also be viewed
online at

http://dev.mysql.com/doc/relnotes/mysql/8.0/en/news-8-0-4.html

Enjoy!

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

Note

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
platform.

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
statements:
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
(http://dev.mysql.com/doc/refman/8.0/en/validate-password-transitioning.html).
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
default.

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
removed.
MYSQL_OPT_GUESS_CONNECTION
MYSQL_OPT_USE_EMBEDDED_CONNECTION
MYSQL_OPT_USE_REMOTE_CONNECTION
MYSQL_SET_CLIENT_IP

(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
engine.
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
Considerations
(http://dev.mysql.com/doc/refman/8.0/en/regexp.html#regexp-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
(http://dev.mysql.com/doc/refman/8.0/en/encryption-functions.html).

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
(http://dev.mysql.com/doc/refman/8.0/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)

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
(http://dev.mysql.com/doc/refman/8.0/en/error-log-filtering.html).

* 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
Format
(http://dev.mysql.com/doc/refman/8.0/en/error-log-format.html).

* 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

+ ER_XA_STARTING_RECOVERY

+ ER_XA_RECOVERY_DONE

+ ER_NORMAL_SHUTDOWN

+ ER_SHUTDOWN_COMPLETE

+ ER_RPL_SLAVE_CONNECTED_TO_MASTER_REPLICATION_STARTED

+ ER_RPL_SLAVE_CONNECTED_TO_MASTER_REPLICATION_RESUMED

+ ER_SLAVE_CHANGE_MASTER_TO_EXECUTED

+ ER_GTID_PURGED_WAS_CHANGED

+ ER_GTID_EXECUTED_WAS_CHANGED

+ ER_CHANGED_GTID_MODE

+ ER_RPL_SLAVE_DUMP_THREAD_KILLED_BY_MASTER

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
availability:

+ 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
https://msdn.microsoft.com/en-us/library/7d83bc18.as
px.)

+ 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
table.

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
caching_sha2_password.

+ 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
Authentication
(http://dev.mysql.com/doc/refman/8.0/en/caching-sha2-pluggable-authentication.html)).
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
option.

+ 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
Plugin
(http://dev.mysql.com/doc/refman/8.0/en/upgrading-from-previous-series.html#upgrade-caching-sha2-password).
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
information.
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()
(http://dev.mysql.com/doc/refman/8.0/en/mysql-reset-server-public-key.html).
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
(http://dev.mysql.com/doc/refman/8.0/en/creating-ssl-rsa-files-using-mysql.html#creating-ssl-rsa-files-using-mysql-automatic).
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
#26521654)

* 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
(http://dev.mysql.com/doc/refman/8.0/en/keyring-key-migration.html).

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
(http://dev.mysql.com/doc/refman/8.0/en/restart.html).

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_GeometryCollectionFromText(),
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.
Note
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.
Note
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_GeometryCollectionFromText(),
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
behavior.)
Note
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)

* MySQL now supports CREATE SPATIAL REFERENCE SYSTEM and
DROP SPATIAL REFERENCE SYSTEM statements for creating and
removing spatial reference system (SRS) definitions in
the data dictionary. See CREATE SPATIAL REFERENCE SYSTEM
Syntax
(http://dev.mysql.com/doc/refman/8.0/en/create-spatial-reference-system.html),
and DROP SPATIAL REFERENCE SYSTEM Syntax
(http://dev.mysql.com/doc/refman/8.0/en/drop-spatial-reference-system.html).
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
INFORMATION_SCHEMA ST_SPATIAL_REFERENCE_SYSTEMS table, as
before.

Test Suite Notes

* Documentation for the MySQL Test Suite is now maintained
in the MySQL source tree using Doxygen (see
http://dev.mysql.com/doc/dev/mysql-server/latest/PAGE_MYSQL_TEST_RUN.html).
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
#87136)

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
#26042786)

* 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
Authentication
(http://dev.mysql.com/doc/refman/8.0/en/caching-sha2-pluggable-authentication.html).
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
(http://dev.mysql.com/doc/refman/8.0/en/innodb-moving-data-files-offline.html).
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
INFORMATION_SCHEMA.FILES table:
mysql> SELECT TABLESPACE_NAME, FILE_NAME FROM INFORMATION_SCHEMA.FILES
\G

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:

+ FIL_PAGE_TYPE_LOB_INDEX

+ FIL_PAGE_TYPE_LOB_DATA

+ FIL_PAGE_TYPE_LOB_FIRST

+ FIL_PAGE_TYPE_ZLOB_FIRST

+ FIL_PAGE_TYPE_ZLOB_DATA

+ FIL_PAGE_TYPE_ZLOB_INDEX

+ FIL_PAGE_TYPE_ZLOB_FRAG

+ FIL_PAGE_TYPE_ZLOB_FRAG_ENTRY

* 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
INFORMATION_SCHEMA.INNODB_TABLESPACES table to provide
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.
Warning
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
ORDINAL, PATH, EXISTS PATH, and NESTED PATH or NESTED, as
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
optional.
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 *
-> FROM JSON_TABLE(
-> @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
(http://dev.mysql.com/doc/refman/8.0/en/json-table-functions.html).

* 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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