[ This is part 2 of the announcement ]


Logging Notes

* These error-logging changes have been made:

+ The server is now more forgiving if it cannot find
the configured error-message file (specified using
the lc_messages_dir and lc_messages system
variable). Previously, the server aborted the
startup process and exited. Now the server writes a
message to the error log and defaults to built-in
English messages. This applies to messages the
server writes to the error log and sends to clients.

+ Error logging is being rewritten to use the MySQL
component architecture. Traditional error logging
now is implemented using built-in components, and
logging using the system log is a loadable
component. In addition, a new JSON log writer is
available. The log components to use are controlled
by the new log_error_services system variable. For
more information, see The Error Log
(http://dev.mysql.com/doc/refman/8.0/en/error-log.html).

Bugs Fixed

* Incompatible Change: Plugins such as Group Replication
and X Plugin now use the mysql.session account added in
this version. If you are upgrading from a previous
version which did not include the mysql.session account
you must run mysql_upgrade to ensure the account is
created. If mysql_upgrade is not run, plugins fail to
start with the error message There was an error when
trying to access the server with user:
mysql.session@localhost. Make sure the user is present in
the server and that mysql_upgrade was ran after a server
update. (Bug #26042764)
References: See also: Bug #24311527, Bug #25642343.

* InnoDB: Queries run on INFORMATION_SCHEMA.TABLES
performed more slowly with information_schema_stats set
to latest. (Bug #26197113)

* InnoDB: An ALTER TABLE ... ADD PARTITION operation that
specified a DATA DIRECTORY clause failed to ignore the
TABLESPACE attribute of the table. (Bug #26113652)

* InnoDB: When foreign_key_checks is disabled, a child
table with a foreign key constraint can be created before
the parent table, which can result in a foreign key
constraint failure, as the parent table is unaware of the
constraint. When a table is created, there is now a call
to load foreign key constraints for the table and check
for child tables. (Bug #25976199)

* InnoDB: A parsing error occurred while optimizing a table
with a full-text index. (Bug #25914332)

* InnoDB: Compiling MySQL on Windows with Microsoft Visual
C++ 2015 or macOS 10.12.4 with GCC 4.2.1 or Apple LLVM
version 8.0.0 (clang-800.0.38) returned warnings. (Bug
#25910531)

* InnoDB: In debug builds, an assertion was raised during
bootstrap when the system tablespace file (ibdata1) ran
out of space during creation of doublewrite pages. (Bug
#25872368)

* InnoDB: Incorrect locking order caused a deadlock when
InnoDB attempted to persist an auto-increment counter
value to disk. (Bug #25833228)

* InnoDB: Internal methods for accessing dictionary table
object data did not account for virtual columns. (Bug
#25822154)
References: This issue is a regression of: Bug #23748128.

* InnoDB: The length of a virtual column field in a virtual
index record was less than the expected template column
length. (Bug #25793677)

* InnoDB: In debug builds, shutting down the server with
--innodb-fast-shutdown=0 raised an assertion. (Bug
#25756224)

* InnoDB: The ibd2sdi utility exited when run on an
unsupported file type. (Bug #25738491)

* InnoDB: InnoDB did not set the compression algorithm when
opening a partitioned table. (Bug #25685868)

* InnoDB: An in-place ALTER TABLE operation failed to set
the encryption type, causing a FLUSH TABLES ... FOR
EXPORT operation to assert. (Bug #25672779)

* InnoDB: A latch that was held while registering a file
close caused a hang condition. (Bug #25658467)

* InnoDB: During recovery, prepared transactions were
rolled back if the innodb_force_recovery setting was
greater than 0. (Bug #25651042)

* InnoDB: A CREATE TABLE operation that defined a unique
key with an eight character prefix on a NOT NULL TEXT
field would raise an assertion if a primary key was not
defined. (Bug #25647413)

* InnoDB: Updates to data dictionary tables combined with
updates to InnoDB system tables for full-text search
auxiliary tables raised a lock-related assertion. (Bug
#25610353)

* InnoDB: The server allocated memory unnecessarily for an
operation that rebuilt the table. (Bug #25573565, Bug
#85043)

* InnoDB: Test related code intended to simulate a random
read on a non-existent page raised an invalid assertion.
(Bug #25479538)
References: This issue is a regression of: Bug #25053705.

* InnoDB: With foreign_key_checks disabled, InnoDB
incorrectly printed messages to the error log when
operations were performed on a table that referenced a
non-existent foreign key. (Bug #25365223)

* InnoDB: A DROP TABLE or TRUNCATE TABLE operation could
raise an assertion following a failed online ALTER TABLE
.. ADD INDEX operation. The index root page was dropped
prematurely. (Bug #25357789)

* InnoDB: During a TRUNCATE TABLE operation on a
file-per-table tablespace, a dictionary operation lock
was released before eviction of dirty pages from the
buffer pool, causing a latch order violation. (Bug
#25357789)

* InnoDB: When using an index merge optimizer switch, a
SELECT COUNT(*) operation sometimes returned 0.
Partitioning code incorrectly performed a memcpy instead
of a column copy of columns read by the index, causing
the wrong records to be copied. (Bug #25332330, Bug
#81031)

* InnoDB: After a RENAME TABLE operation that moved a table
to a different schema, InnoDB returned an error on
restart indicating that it could not locate the
tablespace data file. InnoDB failed to update
INNODB_SYS_DATAFILES data dictionary table during the
RENAME TABLE operation. (Bug #25189192, Bug #84038)

* InnoDB: During an ALTER TABLE operation that rebuilt a
table containing a virtual column, InnoDB failed to apply
a concurrent insert log record. (Bug #24961167)

* InnoDB: InnoDB failed to apply the concurrent delete log
for an in-place ALTER TABLE operation due to a virtual
column validation issue. (Bug #24960450)

* Partitioning: Following execution of an ALTER TABLE ...
OPTIMIZE PARTITION statement, names of tablespaces used
by the table were not preserved, and subsequent accesses
to the table eventually caused the server to fail. (Bug
#25512556)

* Replication: When replicating a partitioned table with an
index, on a replication slave where HASH_SCAN was
specified as part of the slave_rows_search_algorithms
setting, the slave I/O thread sometimes stopped with an
error HA_ERR_KEY_NOT_FOUND. (Bug #26137159)

* Replication: A USE statement that followed a SET
GTID_NEXT statement sometimes had no effect. (Bug
#26128931)

* Replication: A misleading warning was issued when the
command FLUSH LOGS or PURGE LOGS BEFORE was used on a
binary log file with an expiry time set, and the binary
log file was in use. The warning related to the file
being in use, and implied that a purge attempt had taken
place, even if the expiry time had not yet been reached.
Now, MySQL checks the expiry time of the binary log file
first, and only then checks whether the file is in use.
So the warning is only issued for an in-use binary log
file that is old enough to be purged. (Bug #25973525)

* Replication: When binlog_checksum=NONE was set on a MySQL
server after startup, and then Group Replication was
started, if an error occurred, the server remained in
RECOVERING state and could not be shut down. (Bug
#25793366)

* Replication: The following Performance Schema replication
tables now continue to be populated when the Performance
Schema is disabled:

+ replication_connection_configuration

+ replication_connection_status

+ replication_applier_configuration

+ replication_applier_status

+ replication_applier_status_by_coordinator

+ replication_applier_status_by_worker
The exception is local timing information (start and end
timestamps for transactions) in the replication tables
replication_connection_status,
replication_applier_status_by_coordinator, and
replication_applier_status_by_worker. This information is
not collected when the Performance Schema is disabled.
(Bug #25694813)

* Replication: In a Group Replication setup where circular
asynchronous replication was implemented between members
of different replication groups, view change log events
were repeatedly replicated between the groups with new
generated GTIDs each time. The fix ensures that view
change log events are ignored outside the named
replication group where they occur, and never generate
new GTIDs. (Bug #25674926)
References: See also: Bug #26049695, Bug #25928854, Bug
#25721175.

* Replication: When first starting the MySQL server
following an installation from RPM, passwword validation
plugin is activated by default (true only for RPM
installations). If binary logging was already enabled at
this time, the activation was logged, even though plugin
activations should not be recorded in the binary log.
(Bug #25672750)

* Replication: The XA START, XA END, XA COMMIT, and XA
ROLLBACK statements, used to perform XA transactions,
were incrementing the counter for a replicate-do-db
filter that named the relevant database. The counter is
no longer incremented for these statements. (Bug
#25669344)

* Replication: In a setup where single-primary Group
Replication was combined with asynchronous replication,
for example with S1 and S2 forming a group and with S2
and S3 functioning as master and slave, secondaries such
as S2 were accepting transactions and these could then
enter the group. The fix prevents secondaries creating an
asynchronous replication channel when belonging to a
single-primary group, and Group Replication cannot be
started when asynchronous replication is running. (Bug
#25574200)
References: See also: Bug #26078602.

* Replication: Group Replication failed to start if the
super_read_only system variable was enabled. (Bug
#25481287, Bug #84733)

* Replication: MySQL 8.0 servers were not able to join a
replication group that contained MySQL 5.7 servers, and
MySQL 5.7 servers in a replication group could not be
upgraded to MySQL 8.0. (Bug #25477979)

* Replication: In the event that a member failed to join a
group the member was not stopping and continued to accept
transactions. To avoid this set your members to have
super_read_only=1 in the my.cfg file. Group Replication
now checks for this setting upon successful start up and
sets super_read_only=0. This ensures that members which
do not successfully join a group cannot accept
transactions. (Bug #25474736, Bug #84728)

* Replication: When mysqlbinlog output from a MySQL 5.7
server was applied on a MySQL 8.0 server, the MySQL 8.0
server generated its own timestamp for the
original_commit_timestamp. The fix ensures that the value
of original_commit_timestamp is correctly set to 0,
meaning that the timestamp is not known. (Bug #25316086)

* Replication: When an existing GTID_NEXT transaction was
assigned a conflicting GTID by the server, Group
Replication generated an assert upon detecting two
transactions with same GTID. This was because Group
Replication generates the GTID after conflict detection,
which is later than with master/slave replication. The
fix relaxes some conditions to only be called when commit
is done and a message has been added to alert you when a
GTID has already been used. (Bug #25232042)

* Replication: If the server was started with the --log-bin
option, discovery of one Performance Schema table with
invalid structure caused all subsequently checked
Performance Schema tables to be marked invalid as well.
(Bug #25041396)

* Replication: Interleaved XA transactions could sometimes
deadlock the slave applier when the transaction isolation
level was set to REPEATABLE-READ. (Bug #25040331)

* Replication: The slave_skip_errors system variable did
not permit error numbers larger than 3000. Thanks to
Tsubasa Tanaka for the patch. (Bug #24748639, Bug #83184)

* Replication: The SQL state of
ER_TRANSACTION_ROLLBACK_DURING_COMMIT was HY00, which is
generic and not suitable for rollback. The SQL state has
been modified to 40000. (Bug #24658431)

* Replication: mysqlbinlog, if invoked with the --raw
option, does not flush the output file until the process
terminates. But if also invoked with the --stop-never
option, the process never terminates, thus nothing is
ever written to the output file. Now the output is
flushed after each event. (Bug #24609402)

* Replication: A memory leak in mysqlbinlog was fixed. The
leak happened when processing fake rotate events, or when
using --raw and the destination log file could not be
created. The leak only occurred when processing events
from a remote server. Thanks to Laurynas Biveinis for his
contribution to fixing this bug. (Bug #24323288, Bug
#82283)

* Replication: Loading and initialization of the Group
Replication plugin failed if no root account was present.
(Bug #24311527)

* Replication: A slave server could lose events not yet
applied when MASTER_AUTO_POSITION=0, both replication
threads were stopped, and the applier delay was changed
using CHANGE MASTER TO MASTER_DELAY=N. (Bug #23203678,
Bug #81232)

* Replication: Transmission of large GCS messages could
take so long the sender appeared to have died. (Bug
#22671846)

* Replication: Multi-threaded slaves could not be
configured with small queue sizes using
slave_pending_jobs_size_max if they ever needed to
process transactions larger than that size. Any packet
larger than slave_pending_jobs_size_max was rejected with
the error ER_MTS_EVENT_BIGGER_PENDING_JOBS_SIZE_MAX, even
if the packet was smaller than the limit set by
slave_max_allowed_packet.
With this fix, slave_pending_jobs_size_max becomes a soft
limit rather than a hard limit. If the size of a packet
exceeds slave_pending_jobs_size_max but is less than
slave_max_allowed_packet, the transaction is held until
all the slave workers have empty queues, and then
processed. All subsequent transactions are held until the
large transaction has been completed. The queue size for
slave workers can therefore be limited while still
allowing occasional larger transactions. (Bug #21280753,
Bug #77406)

* Replication: An incident event that broke replication was
not written to the binary log with a GTID, so that it was
not possible to skip the event using SET gtid_next=value.
Instead, it was necessary to set the relay log file and
relay log positions directly; this meant that, when
autopositioning was enabled, it was necessary first to
disable it, then to set the relay log file and position,
and finally to re-enable autopositioning.
Now in such cases MySQL writes the incident event into
the statement cache, so that a GTID is generated and
written for it prior to flushing, and that the slave
applier works with the change. Then users can skip the
event using the SQL statement SET gtid_next=value,
followed by BEGIN and COMMIT. (Bug #19594845)

* Replication: Issuing SHOW SLAVE STATUS FOR CHANNEL
'group_replication_recovery' following a restart of a
server using group replication led to an unplanned
shutdown. (Bug #85739, Bug #25813258)

* Replication: Setting an empty filter rule using CHANGE
REPLICATION FILTER caused issues when running tests with
UBSan. (Bug #85405, Bug #25702297)

* Replication: When the receiver thread held a lock on the
relay log while queuing an event, clients executing SHOW
SLAVE STATUS or SHOW RELAYLOG EVENTS were blocked. (Bug
#85084, Bug #25584734)

* Replication: Indexes for the Performance Schema
replication_applier_status_by_worker table worked
correctly only for single threaded replication. This was
due to the fact that the indexing relied exclusively on
the SQL thread ID regardless of the existence of any
workers. Now in such cases, the index also considers
worker thread ID when multithreading is enabled on the
slave. (Bug #84646, Bug #25444610)

* Replication: In certain cases, the master could write to
the binary log a last_committed value which was smaller
than it should have been. This could cause the slave to
execute in parallel transactions which should not have
been, leading to inconsistencies or other errors. (Bug
#84471, Bug #25379659)

* Replication: When using
group_replication_ip_whitelist=AUTOMATIC, IPs in the
private network are permitted automatically, but some
class C IP addresses were not being permitted correctly.
(Bug #84329, Bug #25503458)

* Replication: The replication applier thread returns Error
3002 ER_INCONSISTENT_ERROR when there is a difference
between an expected error number and the actual error
number. It is now possible to ignore this error by using
3002 with slave_skip_errors. (Bug #83186, Bug #24753281)

* Replication: MySQL lost its GTID position following a
restart when a dump from mysqldump had been used to load
data.
To keep this problem from occurring, the
mysql.gtid_executed table is now excluded automatically
from dumps made by mysqldump. (Bug #82848, Bug #24590891)

* Replication: It was possible to set binlog_format without
causing an error when there were open temporary tables.
(Bug #82467, Bug #24411680)

* Replication: Corruption of relay logs for one channel in
multi-source replication caused good channels not to be
initalized during a server restart. In addition, when run
with --skip-slave-start=false, the server also failed to
start slave threads for those channels which were in good
condition, despite the fact that it should have started
the slave threads for all good channels.
Now, regardless of any errors on other channels, the
server attempts to create and initialize channels that
are in good condition, and starts slave threads for the
good channels if --skip-slave-start is disabled. As part
of this fix, START SLAVE and STOP SLAVE, which are
intended to operate on all channels, are also modified
such that they continue executing on all good channels
even if they find bad channels among them. (Bug #82209,
Bug #24285104)

* Replication: The SQL thread was unable to GTID skip a
partial transaction. (Bug #81119, Bug #25800025)

* Replication: It was possible for FLUSH LOGS to write a
Rotate_log_event into an uninitialized log file. (Bug
#80368, Bug #22732184)
References: See also: Bug #23531998, Bug #81734.

* Microsoft Windows: On Windows, the Docs/INFO_SRC file was
missing the build-date entry. (Bug #25799855)

* JSON: NULLIF() failed with an assertion error in debug
builds if the result from this function was used in a
JSON context. This result can now be used safely as a
JSON value.
This fix includes using DBUG_ASSERT() for handling this
error instead of DBUG_ABORT(), which caused debugging
problems on some platforms. (Bug #25818544)
References: See also: Bug #21383497, Bug #21383530.

* JSON: The internal Json_array now uses a std::vector
instead of a Prealloced_array to store its elements,
which reduces the amount of heap space required by them.
(Bug #85877, Bug #25867454)

* The mysqld_pre_systemd script in RPM packages found the
error log setting in option files if specified as
log-error but not as log_error, though both are
permitted. (Bug #26148391, Bug #86466)

* ALTER TABLE ... ADD PARTITION statements could cause a
server exit. (Bug #26132947)

* SET PERSIST did not work for X Plugin system variables.
(Bug #26115672)

* REFERENCES privilege checking could use the incorrect
database in some cases. (Bug #26106655)

* With the gtid_mode system variable not set in a .cnf
option file or on the command-line, the server failed to
restart after using SET PERSIST or SET GLOBAL to set
gtid_mode to ON_PERMISSIVE. (Bug #26085712)

* During prepared statement execution, too many bytes of a
buffer could be read. (Bug #26042934, Bug #85937)

* Dynamic privileges were not loaded when the server was
started using the --initialize option. (Bug #26005645)

* Debian client packages were missing information about
conflicts with akonadi-backend-mysql packages. (Bug
#26002288)

* mysqldump could write database names in USE statements
incorrectly. (Bug #25998635)

* If the mysql_stmt_close() C API function was called, it
freed memory that later could be accessed if
mysql_stmt_error(), mysql_stmt_errno(), or
mysql_stmt_sqlstate() was called. To obtain error
information after a call to mysql_stmt_close(), call
mysql_error(), mysql_errno(), or mysql_sqlstate()
instead. (Bug #25988681)

* Upgrading from MySQL 5.7 to MySQL 8.0 failed during data
dictionary creation due to table names that exceeded the
64 character length limit. (Bug #25973237, Bug #86120)

* Queries could be cached incorrectly, leading to incorrect
query results, under these circumstances: InnoDB table;
rows are being inserted but have not yet been committed;
a query uses the table as a base table in a derived
table; the optimizer chooses to materialize the derived
table. (Bug #25943038, Bug #86047)

* mysqld misbehaved if compiled with AddressSanitizer
enabled and invoked with --basedir= (that is, with an
empty option value). (Bug #25914296, Bug #85994)

* The ST_LatFromGeohash(), ST_LongFromGeohash(), and
ST_PointFromGeohash() functions did not allow data that
originated from a CHAR column. (Bug #25912557, Bug
#85981)

* Attempting to drop a data file from a tablespace with
multiple data files returned a duplicate file name error.
(Bug #25858461)

* An attribute was added to data dictionary client method
declarations to generate compilation warnings when return
values are ignored. (Bug #25840927)

* The data dictionary class hierarchy was simplified. (Bug
#25835968, Bug #85811)

* A restriction that prevented the data dictionary object
update function (Dictionary_client::update) from being
called twice on the same object was removed. (Bug
#25833932, Bug #85800)

* On Ubuntu platforms, the MySQL service script did not
terminate correctly if the user running the script did
not have permission to access the data directory or PID
file. (Bug #25825833)

* String comparison queries on the
INFORMATION_SCHEMA.CHARACTER_SETS.DESCRIPTION field were
case sensitive, which is a regression from earlier
releases. (Bug #25824297)

* Man pages for a few utilities were missing from
Debian/Ubuntu packages. (Bug #25811814)

* An INFORMATION_SCHEMA view executed in LOCK TABLES mode,
using the SERIALIZABLE isolation level, and with
autocommit disabled, failed to use non-locking reads,
which could block DDL operations or cause deadlocks. (Bug
#25811413)

* Table locking failures could occur if tables were used by
a trigger for which a trigger of the same name existed in
another database and the database names differed only in
lettercase. (Bug #25807393)

* An in-place MySQL upgrade failed if a .TRG file was
missing the created line for the trigger definition.
(This problem is unlikely to occur for upgrades to MySQL
8.0 from 5.7 because the created line is present for
MySQL 5.7.2 and higher.) (Bug #25805260, Bug #85704)

* The field-t unit test failed to run with AddressSanitizer
enabled. Thanks to Laurynas Biveinis for the patch. (Bug
#25803823, Bug #85678)

* Debian client packages were missing information about
conflicts with native packages. (Bug #25799475)

* The CREATE_OPTIONS column of the
INFORMATION_SCHEMA.TABLES table was treated as having the
binary collation, so functions such as UPPER() and
LOWER() did not have the intended result. (Bug #25793429)

* After importing a table with DECIMAL column, accessing
the table raised an assertion. (Bug #25792649)

* ALTER TABLE could fail when the default character set
changed to utf8mb4 due to incorrect column length
calculations. (Bug #25779239, Bug #85614)

* If a server component deinit() method failed, the
component was still unloaded. (Bug #25764325)

* Stored program execution could fail for DEFINER accounts
with expired passwords even if they were locked and could
not be used to connect to the server. Now DEFINER
accounts are not checked for expired passwords if they
are locked. (Bug #25741966)

* DISTINCT operations on temporary tables could produce
incorrect results due to allocation of too-small
comparison keys. (Bug #25740550, Bug #85518)

* In optimizer trace output, num_tmp_files did not actually
indicate number of files. It has been renamed to
num_initial_chunks_spilled_to_disk and indicates the
number of chunks before any merging has occurred. (Bug
#25733784, Bug #85487)

* The Perl path in #! lines at the beginning of Perl
scripts has been adjusted to /usr/local/bin/perl for
FreeBSD 11. (Bug #25719975)

* With the IGNORE_SPACE SQL mode enabled, syntax error
messages always reported line 1 as the line number. (Bug
#25717617)

* mysqldump failed to properly quote certain identifiers in
SQL statements written to the dump output. (Bug
#25717383)

* Dropping a tablespace without that associated tablespace
file failed with an error stating that the tablespace
dictionary object is invalid. (Bug #25717019)

* Client preauthorization by the server was missing a
length check for a length-encoded string. (Bug #25714674)

* In debug builds, a CREATE TABLESPACE operation raised an
invalid assertion when using the NDB storage engine. A
validation function that checked for zero-length data
files did not apply to NDB tablepaces and was removed.
(Bug #25700242)

* For debug builds, EXPORT_SET() operations could raise an
assertion for some arguments. (Bug #25688192)

* For debug builds, the assertion added for Bug#59686 was
too strict and could be raised when it should not have
been. (Bug #25685958)
References: See also: Bug #59686.

* A code refactoring in MySQL 8.0.1 caused several
assertions to be raised in debug builds. (Bug #25669590,
Bug #25669606, Bug #25669580, Bug #25688504)
References: This issue is a regression of: Bug #25221172,
Bug #84103.

* For some double-precision calculations, overflow could
occur when calculating the exponent part. (Bug #25664323)

* SHOW INDEX output was inconsistent for a FULLTEXT index
defined on multiple columns. (Bug #25659276)

* During a group commit, the stack could incorrectly be
reported exhausted, leading to stack overflow. (Bug
#25656875)

* When the character set of one string comparison operand
was a superset of the character set of the other operand,
some comparisons were disallowed that should be permitted
by converting the operand with the "smaller" character
set to the "larger" character set. utf8mb4 and utf32 are
considered to be a superset of any other encoding. (Bug
#25642319, Bug #85224)

* An in-place (binary) upgrade could change the default
character_set_client and character_set_connection
variables for stored routines, possibly resulting in
different routine behavior. (Bug #25633041)

* For debug builds, the partitioning handler could
inappropriately evaluate generated column expressions in
UPDATE statements, resulting in a raised assertion. (Bug
#25615803, Bug #85179)

* In strict SQL mode, an ER_TRUNCATED_WRONG_VALUE error
could be converted from a warning to an error but then
ignored, leading to a raised assertion. (Bug #25586959,
Bug #25586673)

* Failure occurred for ALTER TABLE on an ARCHIVE table
containing a NOT NULL column having a geometry data type.
For debug builds, an assertion was raised. For non-debug
builds, an error occurred. (Bug #25582178, Bug #85059)

* For debug builds, an assertion could be raised for DROP
TRIGGER of a trigger for a table used by a view. (Bug
#25581925)

* For upgrades from MySQL 5.7 to MySQL 8.0, the server
wrote unnecessary parsing warnings to the error log.
These messages are now suppressed. (Bug #25518436, Bug
#84889)

* The server exited abnormally attempting to access invalid
memory. (Bug #25501659)

* The maximum length of the name field in the
column_type_elements table in the data dictionary was
extended from 255 bytes to 1020 bytes to accommodate long
ENUM and SET values that could result from using a
multibyte character set.
When using a multibyte character set, a single ENUM or
SET element occupies a maximum of M x w bytes in the
column type definition in the data dictionary, where M is
the element literal length and w is the number of bytes
required for the maximum-length character in the
character set.
In prior releases, the maximum supported length of an
individual ENUM or SET element depended on the number of
elements in the type. Thus, there could be a single
element with (M x w) = 64K, or 64K elements with (M x w)
= 1.
The maximum supported length of an individual ENUM or SET
element is now M <= 255 and (M x w) <= 1020, regardless
of the number of elements in the type. (Bug #25481355)

* With mysqld secured by TCP wrappers and the hosts.allow
and hosts.deny files configured to restrict access from
an IP address, connection attempts from that address
resulted in too many messages to the error log. (Bug
#25476479, Bug #84708)

* mysqlpump no longer includes the slave_master_info and
slave_relay_log_info tables in dumps of the mysql system
database. Restoring a dump file containing these tables
caused problems by changing the replication state
improperly. (Bug #25469190)

* Changes made by calling mysql_options() to set
MYSQL_OPT_SSL_MODE could be affected by later
mysql_options() calls. Now setting MYSQL_OPT_SSL_MODE is
unaffected by later mysql_options() calls. (Bug
#25452210)

* A race condition could occur for CREATE TABLE statements
with DATA DIRECTORY or INDEX DIRECTORY clauses. (Bug
#25451091)

* With AddressSanitizer enabled, compiling the keyring_file
plugin produced One-Definition Rule violations. (Bug
#25448205)

* ALTER TABLE ... MODIFY on a DATETIME NOT NULL column
using an AFTER clause resulted in an
ER_INVALID_USE_OF_NULL error. (Bug #25385334)

* The range optimizer could create an incorrect query tree,
resulting in a server exit. (Bug #25369742, Bug
#25586531)

* mysqld_failed to start the server if the --datadir option
was specified with a relative path name. (Bug #25364806)

* XA PREPARE, XA ROLLBACK, and XA COMMIT for a transaction
from a disconnected session did not take a global commit
lock and modified the binary log and InnoDB redo log even
when FLUSH TABLES WITH READ LOCK was in effect. This
could lead to inconsistent backups when backup tools
assumed that the server was in a read-only state. (Bug
#25364178, Bug #84442)

* GROUP_CONCAT(DISTINCT) returned nonunique values if the
data size was greater than the value of the
tmp_table_size system variable. (Bug #25331425, Bug
#84320)

* The fix for Bug #78777 had different effects depending on
whether the Performance Schema is enabled. (Bug
#25309017, Bug #84305)
References: This issue is a regression of: Bug #78777.

* An aggregate function in some nested queries could cause
a server exit. (Bug #25303711)

* Virtual generated column expressions that used any of the
BIN_TO_UUID(), CONV(), or HEX() functions could cause
problems if the connection character set was changed. In
this context, the table character set is now used for
these functions regardless of connection character set.
(Bug #25287633)

* The Rewriter plugin did not perform locking properly if
the read_only system variable was enabled. (Bug
#25264253)

* With read_only enabled, creation of non-TEMPORARY tables
by non-SUPER users was permitted under certain
conditions. (Bug #25250768)

* For a table having a TIMESTAMP or DATETIME column having
a default of CURRENT_TIMESTAMP, the column could be
initialized to 0000-00-00 00:00:00' if the table had a
BEFORE INSERT trigger. (Bug #25209512, Bug #84077)

* On Windows, Time values in SHOW PROCESSLIST output
drifted higher over time. (Bug #25101724, Bug #83019)

* An assertion was raised when a create function at server
bootstrap attempted to evaluate non-resolved expressions.
(Bug #24961932)

* The number of data dictionary cache lookups was reduced,
and ALTER TABLE handling of triggers was improved help
ensure trigger persistence in case of a server exit
during ALTER TABLE processing. (Bug #24930129, Bug
#83473)

* Certain queries against InnoDB tables that used a primary
key and a subquery could return incorrect results if the
index_merge_intersection flag of the optimizer_switch
system variable was enabled. (Bug #24829050, Bug #79675)

* On x86 machines, the uint3korr() macro read 4 bytes of
data instead of the intended 3 bytes. (Bug #24807826, Bug
#83264)

* An assertion was raised during a fetch operation by the
memcached plugin. (Bug #24605783)

* Queries that contained UNION in a subquery and GROUP BY
could return incorrect results. (Bug #24595639)

* Some syntactically incorrect CREATE INDEX statements
could cause a server exit rather than a syntax error.
(Bug #24593992)

* An in-place MySQL upgrade failed if the
innodb_table_stats or innodb_index_stats tables were not
present in the mysql system database. (This problem
should not occur for upgrades to MySQL 8.0 from 5.7
because those tables are present in MySQL 5.7.) (Bug
#24557143)

* Incorrect behavior could occur for INSERT statements
executed in stored-program or prepared-statement context,
if the VALUES part of an ON DUPLICATE KEY UPDATE clause
referred to a BLOB value in the INSERT column list. (Bug
#24538207, Bug #25361251, Bug #25530880, Bug #25684790)

* systemd support scripts in Debian packages contained
hardcoded references to the data directory, making it
difficult to change the data directory using --datadir.
(Bug #24398446, Bug #82417)

* MySQL failed to compile under macOS 10.10.5 using Clang.
(Bug #24352163, Bug #82340)

* If a REPLACE statement tried to update a row in a table
containing a virtual generated column of type BLOB,
subsequent DML statements could behave incorrectly. (Bug
#23573575)

* EXPLAIN for single-table UPDATE or DELETE statements
could raise an assertion attempting to optimize away
subqueries. (Bug #23209903)

* For builds with AddressSanitizer enabled, the
ST_Simplify() function could attempt to use already freed
memory. (Bug #23023817)

* Compiler flags were adjusted to eliminate numerous
warnings that occurred when compiling the keyring_file
plugin using Clang. (Bug #22834591, Bug #80524)

* If enabling the Event Scheduler caused an event defined
as ON COMPLETION NOT PRESERVE to be dropped because its
execution time had passed, the drop event was not written
to the binary log, causing slaves not to replicate it and
replication failure if an event of the same name was
created later. (Bug #22150112)

* For some CREATE TABLE ... SELECT statements, adding an
ORDER BY clause changed column data types, or caused an
assertion to be raised for debug builds. (Bug #16833464)

* LOAD XML INFILE performance became noticeably slower when
the XML file being read contained a great many spaces,
such as those introduced by indenting or pretty-printing.
Now all leading whitespace is trimmed from each such
value before reading it into memory. (Bug #16212207)

--
MySQL General Mailing List
For list archives: http://lists.mysql.com/mysql
To unsubscribe: http://lists.mysql.com/mysql