[This is part 2 of the announcement]
Bugs Fixed
* Important Change: Importing a dump from a MySQL 5.7
server to a server running MySQL 8.0 often failed with
ER_WRONG_VALUE_FOR_VAR when an SQL mode not supported by
the 8.0 server was used. This could happen frequently due
to the fact that NO_AUTO_CREATE_USER is enabled by
default in MySQL 5.7 but not supported in MySQL 8.0.
The behavior of the server in such circumstances now
depends on the setting of the pseudo_slave_mode system
variable. If this is false, the server rejects the mode
setting with ER_UNSUPPORTED_SQL_MODE. If
pseudo_slave_mode is true, the server ignores the
unsupported mode and gives a warning. Note that
mysqlbinlog sets pseudo_slave_mode to true prior to
executing any SQL. (Bug #90337, Bug #27828236)
* InnoDB: MySQL would not start on Solaris X86. The static
thread-local 'tables' variable in the TempTable storage
engine was not properly initialized. (Bug #28987365)
* InnoDB: Latching logic used during deadlock detection was
simplified. (Bug #28904966)
* InnoDB: An invalid record offset for an old version of a
clustered index record raised a debug assertion. (Bug
#28825617)
References: This issue is a regression of: Bug #25540277.
* InnoDB: The minimum DML delay imposed when the length of
the history list exceeds innodb_max_purge_lag was
decreased from 5000 microseconds to 5 microseconds. (Bug
#28813453)
* InnoDB: An incorrect lock order caused a deadlock when
one thread attempted to drop a table while another
created an encrypted tablespace. (Bug #28774259)
* InnoDB: ALTER TABLESPACE failed to ignore unsupported
tablespace attributes. (Bug #28656611)
* InnoDB: Implicit to explicit lock conversion logic was
simplified and optimized. (Bug #28637472)
* InnoDB: A fragment page allocation failure raised an
assertion. (Bug #28615893)
* InnoDB: Incorrectly placed debug points caused flushed
LOB pages to be considered corrupt. (Bug #28607368)
* InnoDB: The TempTable storage engine incorrectly created
temporary files in the system temporary directory instead
of the directory defined by the tmpdir variable. (Bug
#28598943)
* InnoDB: Attempting to drop a table with a name similar to
that of a full-text search auxiliary table caused an
assertion failure. (Bug #28577083)
* InnoDB: A function called by an UPDATE query did not
account for virtual columns. (Bug #28560650)
* InnoDB: An incorrect key was defined for the buffer pool
zip hash mutex. (Bug #28556539)
* InnoDB: Deadlock handling for background transactions
that involve the mysql.innodb_table_stats and
mysql.innodb_index_stats tables was modified. The tables
were incorrectly included in an assertion that is
triggered when internal tables are included in a deadlock
cycle. (Bug #28523042, Bug #92069)
* InnoDB: Setting innodb_spin_wait_delay to a high value
caused an assertion failure when attempting to shut down
the server. To prevent this failure from occurring, the
innodb_spin_wait_delay maximum value was reduced to 1000.
(Bug #28489407, Bug #91973)
* InnoDB: An ON DELETE CASCADE operation on table with a
foreign key constraint and an indexed virtual column
caused the server to exit. (Bug #28470805)
* InnoDB: An incorrectly written DML log involving a
virtual column value raised an assertion. (Bug #28448853)
* InnoDB: A RENAME TABLE operation failed when run on a
table created outside of the MySQL data directory using
the DATA DIRECTORY clause. (Bug #28341514)
* InnoDB: ALTER TABLE ... EXCHANGE PARTITION permitted
partitions with different virtual column definitions to
be exchanged, which resulted in an assertion when InnoDB
later attempted to read from a nonexistent virtual
column. (Bug #28235668)
* InnoDB: A counter was added for redo log write and flush
requests that occur during transaction commit. The
counter is used by the log writer thread to compute the
average time between consecutive requests. When the
average time is greater than 100 microseconds, log writer
threads do not use spin delay and instead wait on request
events with a 10 microsecond timeout limit.
A log writer thread implementation issue that could cause
a hang was also fixed. (Bug #28062382, Bug #28444247, Bug
#28616442, Bug #90890)
* InnoDB: An assertion was raised when attempting to add
rollback segments to newly added undo tablespace that was
not fully initialized. (Bug #27914054)
* InnoDB: Foreign key constraints were ignored after a
RENAME TABLE operation. (Bug #27453180, Bug #89441)
* InnoDB: Using the O_DIRECT_NO_FSYNC innodb_flush_method
setting could cause the system to hang due to file system
metadata becoming unsynchronized. To prevent this issue
from occurring in O_DIRECT_NO_FSYNC mode, InnoDB now
calls fsync() after creating a new file, after increasing
file size, and after closing a file. The fsync() system
call is still skipped after each write operation.
With the changes described above, O_DIRECT_NO_FSYNC mode
can now be safely used on EXT4 and XFS file systems. (Bug
#27309336)
* InnoDB: Specifying the CREATE TABLE or ALTER TABLE
ENCRYPTION option with an empty string failed to raise an
error and was interpreted as a default setting, which is
ENCRYPTION='N'. Specifying an empty string is now treated
as invalid and raises an error. (Bug #27177845)
* InnoDB: Partition suffixes (the #P# part of a partitioned
table name) were not converted to lowercase when moving
tablespace data files from a MySQL instance on Windows to
a MySQL instance on Linux where the
lower_case_table_names variable was set to 1. Failure to
fully convert table names to lowercase caused errors
later when attempting to rename tables. (Bug #26925260)
* InnoDB: An assertion was raised when attempting to write
to a tablespace file greater than 4GB in size on a 64-bit
Windows system. The failure was due to a narrowing cast.
(Bug #26636815, Bug #87423)
* Partitioning: Trying to perform an instant add column on
a discarded tablespace led to an assert. An error is now
returned in such cases. (Bug #28517843)
* Partitioning: Repeated ALTER TABLE statements on
partitioned tables containing BLOB or TEXT columns were
not always handled correctly. (Bug #28491099)
* Partitioning: ALTER TABLE ... EXCHANGE PARTITION did not
work when the partitioned table had one or more partition
definitions using the DATA DIRECTORY option. This fix
supports partitioned tables using the InnoDB storage
engine only. (Bug #19730200)
* Replication: Depending on the value of
group_replication_exit_state_action, the behavior of
members exiting a group was not consistent. To harmonize
the behavior of members exiting the group regardless of
the error scenario, now when a member with
group_replication_exit_state_action=READ_ONLY exits the
group unintentionally, the super_read_only mode that the
member had when started is restored. This makes the
behavior consistent with that of a member with
group_replication_exit_state_action=ABORT_SERVER. (Bug
#28971639, Bug #28526591)
* Replication: When adding a new member to a group, if the
certification information was too big to transmit, an
event was generated that caused failures in all group
members. To avoid this situation, now if the
certification information is too large an error is
generated which makes the joining member leave the group.
(Bug #28900691, Bug #28443958)
* Replication: When a group was being reconfigured online,
for example using
group_replication_switch_to_multi_primary_mode or
group_replication_set_as_primary, there was a chance that
stopping a member could result in an unexpected stop.
Now, when you issue STOP GROUP_REPLICATION, if the member
is part of an online group that is being reconfigured,
the group coordinator is informed that Group Replication
is stopping and the member waits for the online
configuration to finish. (Bug #28807260)
* Replication: The metadata written to the binary log for
CREATE TABLE statements includes character set
information for the character columns in the table.
Previously, when the mysqlbinlog option
--print-table-metadata was specified, a default character
set was printed for the table. This default character set
was the character set that appeared most frequently in
the table columns, and might not match the default
character set that had been specified for the table.
mysqlbinlog now prints the character set for each column
individually. The columns are also printed on separate
lines. (Bug #28774144)
* Replication: Character set information was not written to
the binary log as part of the table metadata for ENUM and
SET columns. This information is now added when
binlog_row_metadata=FULL is set, which produces extended
metadata. (For character columns, character set
information is also added with
binlog_row_metadata=MINIMAL.) (Bug #28706307)
* Replication: When stopping replication, any channels that
had pending transactions could cause a deadlock in Group
Replication. (Bug #28636768, Bug #28365855)
* Replication: A patch to correct the handling of quotes
for identifiers in ROLLBACK TO SAVEPOINT statements in
the binary log was not correctly applied to subsequent
MySQL versions. (Bug #28569645)
* Replication: Following a patch in MySQL 5.7.23, LOAD DATA
statements stopped statement-based replication from a
MySQL 5.7.22 master to a replication slave at a later
release. The problem has now been fixed. (Bug #28541204,
Bug #92132)
* Replication: In some circumstances, the CHANGE MASTER TO
statement could not be used on a replication slave if the
master info log had been changed from a table
(master_info_repository=TABLE) into a file
(master_info_repository=FILE). (Bug #28529558)
* Replication: mysqlbinlog incorrectly added statements to
set the sql_require_primary_key system variable (which
was introduced in MySQL 8.0.13) to ON for events
involving DML SQL statements. The check carried out when
the system variable is set to ON is only relevant for DDL
SQL statements that create new tables or alter the
structure of existing tables. (Bug #28524803)
* Replication: When the system variables
binlog_transaction_dependency_tracking and
binlog_transaction_dependency_history_size were set or
read, the types of lock that were required could result
in a deadlock scenario, because the same locks were also
required for working with the active binary logs. A new
lock type is now used instead for access to the
transaction dependency tracking system variables, so that
this deadlock cannot occur. (Bug #28511326, Bug #91941,
Bug #28537209, Bug #92108)
* Replication: An assertion was raised in debug builds if
an implicit commit was attempted when the GTID value for
the next transaction had not yet been determined
(gtid_next=NOT_YET_DETERMINED). The gtid_next system
variable has this value immediately after the
internal-use statement BINLOG has been issued by
mysqlbinlog to execute a format description event. If a
statement with an implicit commit was attempted next
(such as a CREATE TABLE statement), the gtid_next setting
did not transition to AUTOMATIC state, and was left in an
unacceptable state. If autocommit was on, the error
ER_CANT_SET_GTID_NEXT_TO_ANONYMOUS_WHEN_GTID_MODE_IS_ON
was also logged when the statement was attempted.
To fix this issue, the use of the BINLOG statement is now
prevented during transactions if it would change the
state of gtid_next. The error
ER_VARIABLE_NOT_SETTABLE_IN_TRANSACTION is returned if
this is attempted. Also, when GTIDs are in use and the
value of gtid_next is NOT_YET_DETERMINED, the next
statement must either explicitly set gtid_next to a valid
value or leave the GTID state unaffected. Otherwise the
error
ER_CANT_SET_GTID_NEXT_TO_ANONYMOUS_WHEN_GTID_MODE_IS_ON
is returned. (Bug #28490793, Bug #91980)
* Replication: When group_replication_exit_state_action is
set to ABORT_SERVER, the Group Replication plugin now
uses the new component service added by WL#12003
(https://dev.mysql.com/worklog/task/?id=12003) to
shutdown MySQL. (Bug #28401703)
* Replication: When you used
group_replication_switch_to_single_primary_mode(), if a
member which also had an asynchronous channel encountered
an error, the asynchronous replication channel was not
stopped correctly, and the server could stop
unexpectedly. (Bug #28382590)
* Replication: The PURGE BINARY LOGS TO 'log_name'
statement failed for binary log files that had been moved
to another location using mysqlbinlogmove. Such files are
still listed in the binary log index file, but they are
listed using an absolute path, rather than a path
relative to the directory where the binary log files are
normally stored. MySQL Server can now locate and purge
moved binary log files successfully. (Bug #28284624)
* Replication: It was possible to use the group coordinator
based UDFs which configure a group, such as
group_replication_switch_to_single_primary_mode, while
members were in the UNREACHABLE or RECOVERING state, and
this caused the operation to wait until all members
became ONLINE. This could result in the group coordinator
operation never completing successfully. Now, if you
issue any of these UDFs on a group in this state, an
error is returned. Ensure all members are ONLINE before
attempting to configure the group using the UDFs. (Bug
#28284355)
* Replication: When binlog_format is set to MIXED, if a
function contained DML statements that applied to a
temporary table, and also a DROP TEMPORARY TABLE
statement, the function call was not written to the
binary log, which caused replication errors. The function
call is now written to the binary log in mixed
replication mode if the function contains DML statements
that operate on a temporary table. (Bug #28258992)
* Replication: If autocommit was set to 0 for a replication
slave or Group Replication group member where GTIDs were
in use and super_read_only=ON was set, server shutdown
was prevented by a transaction that did not complete. The
transaction was attempting to save GTIDs to the
mysql.gtid_executed table, but the update failed because
super_read_only=ON was set. (With autocommit set to 1,
the transaction would complete in this situation, and the
mysql.gtid_executed table would instead be updated at
server startup.) Now, the check for the super_read_only
setting is skipped for this task, so the transaction is
able to save the GTIDs to the mysql.gtid_executed table
and complete regardless of the combination of
super_read_only and autocommit settings. (Bug #28183718)
* Replication: An assertion was raised in debug builds if
an XA ROLLBACK statement was issued for an unknown
transaction identifier when the gtid_next value had been
set manually. The server now does not attempt to update
the GTID state if an XA ROLLBACK statement fails with an
error. (Bug #27928837, Bug #90640)
* Replication: An assertion was raised in debug builds if a
SELECT... FOR UPDATE statement was issued immediately
after a transaction was committed or rolled back, and the
transaction had been assigned a GTID manually using the
gtid_next session system variable. After gtid_next has
been used to set a GTID for a transaction, and the
transaction has been committed or rolled back, another
explicit SET GTID_NEXT statement must be issued before
any other statement, otherwise the gtid_next value is
left undefined. The SELECT... FOR UPDATE statement caused
a GTID consistency violation in this situation because it
acquired write locks, although it did not make any
changes. SELECT... FOR UPDATE statements that acquire
write locks now return an error in this situation. (Bug
#27903848, Bug #90547)
* Replication: Under heavy loads, a race condition in
binary log group commit could cause the server to stop
unexpectedly. The tracking of transaction commits has
been changed to prevent this situation. (Bug #27556117)
* Replication: The value returned by a SHOW SLAVE STATUS
statement for the total combined size of all existing
relay log files (Relay_Log_Space) could become much
larger than the actual disk space used by the relay log
files. The I/O thread did not lock the variable while it
updated the value, so the SQL thread could automatically
delete a relay log file and write a reduced value before
the I/O thread finished updating the value. The I/O
thread then wrote its original size calculation, ignoring
the SQL thread's update and so adding back the space for
the deleted file. The Relay_Log_Space value is now locked
during updates to prevent concurrent updates and ensure
an accurate calculation. (Bug #26997096, Bug #87832)
* Replication: If the relay log index file was temporarily
locked for viewing by a backup process for a replication
slave, and MySQL Server also attempted to access the file
at that time for rename or delete operations, the backup
completed with warnings, but MySQL Server experienced an
unexpected halt. MySQL Server now retries the file access
operation a number of times in case this or a similar
scenario is the explanation and the file becomes
available again before long. (Bug #25839610)
* Replication: With sync_binlog=1 set, if the binary log
was rotated during a commit before the binary log end
position was updated, replication stopped on the slave
because the server attempted to use the old binary log
end position with the new binary log file. The server now
compares the binary log file name with the active binary
log file when updating the binary log end position, so
that the issue does not occur. (Bug #22252394, Bug
#25524203, Bug #84752)
* Replication: When a member joined a group that had a
constant peak load, the member might not be able to move
from the RECOVERING to the ONLINE state. The cause was
that:
+ the member was waiting in a loop for the complete
queue of transactions that arrived during recovery
to be applied, while new transactions were still
arriving.
+ even when the complete queue had been applied, the
member was also checking that the applier was
paused, which is unlikely to happen in a continuous
peak workload.
Now, when the recovery completion policy is waiting for
transactions to be applied, the member first waits until
one of the following conditions is fulfilled:
+ the transactions to apply fit within the flow
control configuration. In other words, the
transactions to be applied can be applied during the
next flow control iteration;
+ no transactions are being queued or applied, in the
case of an empty recovery queue.
Then, the member waits for the currently queued
transactions in the group_replication_applier channel to
be applied, before the member state changes to ONLINE.
(Bug #89582, Bug #27511404)
* Microsoft Windows: MySQL Installer could fail after
failure to remove an existing MySQL service. This is now
treated as nonfatal so that installation operations can
continue, but might require a system restart to permit
service cleanup. (Bug #29016677, Bug #93048)
* Microsoft Windows: When multiple instances of mysqld were
started with the --no-monitor option on the same host for
same user, the SHUTDOWN command shut down the wrong
server process. This fix creates a unique shutdown event
name for use with --no-monitor by appending the process
ID of the process. (Bug #28723675)
* X DevAPI: When using the X Protocol, a stored procedure
called with a user variable as an OUT parameter did not
set the variable's value. (Bug #91907, Bug #28458752)
* JSON: Iteration over JSON objects resulted in unnecessary
allocation of strings. (Bug #28975640)
* JSON: Conversion of JSON values to text caused linear
growth of the destination string, resulting in an
unnecessarily high number of reallocations. Now this
process uses exponential growth instead, to reduce the
number of allocations required. (Bug #28949700)
* JSON: YEAR values were stored as opaque data in JSON;
when JSON documents containing YEAR values were converted
to text, the YEAR values were shown as base64-encoded
strings. To resolve this issue, YEAR values are now
stored as unsigned integers, which are shown as numbers
when converted to text. An additional benefit of this fix
is that less storage space is now required for YEAR
values within JSON documents. (Bug #28947107)
* JSON: Hit an assert when attempting to execute UPDATE or
DELETE on an ARCHIVE table containing a JSON column. (Bug
#28923281)
* JSON: When trying to select from a JSON column of a
FEDERATED table, the server returned
ER_INVALID_JSON_PATH_CHARSET Cannot create a JSON value
from a string with CHARACTER SET 'binary'.
In addition, neither DELETE or UPDATE had any effect on a
FEDERATED table containing a JSON column. (Bug #28877215)
* JSON: A query of the form SELECT jt.* FROM t1,
JSON_TABLE(t1.c, '$[*]' COLUMNS (num INT PATH '$[0]')) AS
jt failed due a permissions error even though the user
executing the query had the SELECT privilege on column c.
(Bug #23254268)
* The code contributed by Facebook for the feature
implemented by Bug#27855592 was updated. (Bug #28950397)
References: See also: Bug #27855592.
* On SuSE Linux, spurious EBUSY return values from
pthread_mutex_destroy() were not handled. (Bug #28948462)
* mysqld_safe and mysqld_multi were incorrectly included in
client-only packages. (Bug #28942508)
* Mishandling of host cache locking could cause a server
exit. (Bug #28936159)
* MySQL Enterprise Firewall did not work well if the
audit_log plugin was installed. (Bug #28930885, Bug
#93184)
* Corrections were made to enable successful builds under
Visual Studio on Windows. (Bug #28892711, Bug #93077)
* Previously, the COMPILATION_COMMENT CMake option was used
by the server (for example, to set the version_comment
system variable) and by other programs. However, when the
value contained the word "server", it was inappropriate
for use by other programs. The server now uses the new
COMPILATION_COMMENT_SERVER option. Other programs
continue to use COMPILATION_COMMENT. (Bug #28888510)
* The server permitted creation of databases with the same
name as redo log files, which could result in unexpected
server behavior. Such names are no longer permitted as
database names. (Bug #28867993)
* mysqld_multi could fail to pass the correct datadir value
to mysqld. (Bug #28866662, Bug #90801)
* A debug assertion that checks parameter schema names
during MDL key creation for routines, events, and
triggers to ensure that names are lowercase failed when
encountering a schema name that included multi-byte
character. (Bug #28864244)
* The format specifiers for some error messages were
improved to avoid displaying incorrect numeric values.
(Bug #28860795)
* For debug builds on Windows, unused memory leak checks
were enabled and could slow down the shutdown process.
These checks are now enabled only for specialized builds.
(Bug #28857626)
* mysql_upgrade could fail to upgrade certain system tables
if the sql_require_primary_key system variable was
enabled. (Bug #28855207, Bug #92988)
* Builds configured with -DWITH_LIBWRAP=ON did not compile.
(Bug #28853650, Bug #92983)
* For InnoDB tables, the values of stored or indexed
virtual generated columns that depended on the DEFAULT()
function were not correctly updated by ALTER TABLE, if
the default for a column referenced in this function was
changed by making column nullable. (Bug #28848265)
* Corrections were made to enable successful builds under
Visual Studio on Windows with the /permissive flag turned
on. (Bug #28842878, Bug #92943)
* Builds configured with -DCMAKE_BUILD_TYPE=Release did not
compile. (Bug #28841366, Bug #92945)
* ALTER TABLE now can use the INPLACE algorithm when these
conditions apply:
+ For InnoDB tables, statements that modify generated
stored columns but do not change their type,
expression, or nullability.
+ For non-InnoDB tables, statements that modify
generated stored or virtual columns but do not
change their type, expression, or nullability.
An example of such a change is a change to the column
comment. (Bug #28836543)
* Plugin system variables that had been persisted were not
applied when the plugin was reinstalled. (Bug #28823972)
* EXPLAIN ... FOR CONNECTION could modify another
connection's SQL mode. (Bug #28786981)
* Removal of Sun RPC and XDR from glibc into a separate
libtirpc library caused problems with libasan on some
platforms. (Bug #28785835, Bug #92762, Bug #28897799, Bug
#93116)
* It was possible to hit an assert when comparing two ENUM
values while processing a query of the form SELECT a FROM
table WHERE b = value and there was an index on column b.
(Bug #28769996)
* Concurrent read and write access to the offline_mode
system variable could result in deadlock. (Bug #28761869)
* Triggers were loaded into memory in an incorrect order
when upgrading from MySQL 5.7 to MySQL 8.0, causing an
assertion failure. (Bug #28760011, Bug #92609)
* Joins involving the Performance Schema data_locks table
could produce incorrect results. (Bug #28733170)
* Some multiply-nested subqueries involving the use of
scalar subqueries were not handled correctly. (Bug
#28723670)
* On Ubuntu, the installed
/etc/mysql/mysql.conf.d/default-auth-override.cnf file
was mistakenly created with executable mode. Thanks to
Evgeniy Patlan for the correction contribution. (Bug
#28714840, Bug #92587)
* A memory leak was caused by GET_LOCK() calls with a zero
timeout that failed due to concurrent connections holding
the same user-level lock. (Bug #28714367)
* Heap corruption and a server exit could occur when a
server hosting a large number of tables was started and
stopped repeatedly. (Bug #28705511)
* MySQL Router was missing from MySQL Server MSI packages.
(Bug #28685556)
* The example stored function GTID_SUBTRACT_UUID has been
corrected in the code to match the documented version.
(Bug #28670170)
* CAP_SYS_NICE capability is no longer enabled for mysqld
by MySQL package installers for Linux. (This was done to
facilitate use of resource groups thread priorities.) For
Linux deployments that require access to thread
priorities, consult the MySQL Reference Manual
instructions for enabling CAP_SYS_NICE capability at
Resource Group Restrictions
(http://dev.mysql.com/doc/refman/8.0/en/resource-groups.html#resource-group-restrictions).
(Bug #28670160)
* The internal implementation of the <=> operator was
simplified. (Bug #28660232)
* After a STOP GROUP_REPLICATION statement was issued to
remove a server instance from a group, multiple instances
of the error message "[GCS] Error pushing message into
group communication engine" were logged on the server
instance. The error is now ignored when a server is in
the process of leaving a group or is no longer a member
of a group. (Bug #28658228, Bug #92454)
* The maximum timeout setting for the waiting period before
expelling a suspected Group Replication group member has
been reduced to 3600 seconds (one hour). Previously, the
group_replication_member_expel_timeout system variable
could be set to a value of up to 31536000 seconds. The
new upper limit provides a more reasonable maximum for
the removal of inactive members from the group. The
default setting for the timeout is zero, meaning that
inactive members are liable for expulsion immediately
after the 5-second detection period ends. Specifying a
timeout value is useful to avoid unnecessary expulsions
on slower networks, or in the case of expected transient
network failures or machine slowdowns. (Bug #28656750)
* If the CHARACTER SET attribute of some column was
implicit in JSON_TABLE(... COLUMNS ...), the resulting
column used the global character_set_results as the
default character set. The column now uses the session
character_set_connection and collation_connection values.
(Bug #28643862)
* Adding a functional index on an expression that produced
a row value raised an assertion; now it results in an
error instead. (Bug #28643252)
* In debug builds, creating a trigger after setting
sql-mode to TIME_TRUNCATE_FRACTIONAL caused an assertion
failure. The SQL mode was not present in the sql_mode
column of the mysql.triggers data dictionary table. (Bug
#28642918)
* When using --log-timestamps=SYSTEM, ISO 8601 timestamps
in log messages did not take account of daylight saving
time. (Bug #28632725)
* The arguments for error ER_IB_MSG_720 were computed
incorrectly. (Bug #28629175)
* The server could exit at startup if the option for
specifying a socket file was not specified correctly.
(Bug #28609181)
* It was possible to create an inconsistent foreign key by
adding a parent table with a different storage engine
from the child table, then changing the parent table to
the same storage engine as the child table. (Bug
#28608460, Bug #92317)
* When a server is joining a replication group, it attempts
to connect to the first seed member listed in its
group_replication_group_seeds system variable. If the
connection is refused, the joining member tries to
connect to each of the other seed members in the list in
order. Previously, If the joining member connected to a
seed member but did not get added to the replication
group as a result, the joining member did not make any
further connection attempts. This situation could occur
if the seed member failed after the connection was made,
or if the seed member did not have the joining member's
address in its whitelist and closed the connection, or if
the seed member rejected the joining member's request to
join the group. Now, if the joining member connects to a
seed member but does not manage to join the group, the
joining member continues to try the remaining seed
members in the list in order. (Bug #28602835)
* Given certain patterns of allocations, copies with
rebinds of the allocator, and deallocations, it was
possible for temptable::Allocator to reuse a freed memory
block. This led to failures in the test suite on Windows
platforms. (Bug #28595557)
* Setting time_zone to a negative offset and timestamp to a
low value triggered an assertion when altering routines
and views. (Bug #28590623, Bug #92273)
* Persisting the pid_file system variable to DEFAULT could
result in a value of NULL for subsequent server startups.
(Bug #28589736)
* Incorrect privilege checking could produce an error for
SELECT ... FOR UPDATE statements that executed
successfully in MySQL 5.7. (Bug #28581664, Bug #92254)
* Attempting to rename the parent column of a foreign key
with ALTER TABLE could fail. (Bug #28581468)
* Privileges for RESET PERSIST were not checked correctly.
(Bug #28564239)
* An overflow occurred when calculating
AVG(YEAR(datetime_column)). (Bug #28562930)
* After a server restart, path names of persisted system
variables in the Performance Schema variables_info table
could be calculated incorrectly. (Bug #28561584)
* A partitioned table name check raised an invalid
assertion. (Bug #28556942)
* The handler::create() function could be called with an
error in the condition list, which could prevent an error
in the handler::create() function from being reported
properly. (Bug #28556264)
* For ALTER TABLE, ALGORITHM=INSTANT was incorrectly
rejected on tables created in a MySQL version prior to
8.0.12. (Bug #28554157, Bug #92194)
* mysqlpump did not free all allocated resources when it
encountered an error, resulting in memory leaks. (Bug
#28538971, Bug #92131)
* The COLLATE attribute was rejected for data types in the
COLUMNS clause of the JSON_TABLE() function. (Bug
#28538315)
* For debug builds, the server could exit when attempting
to roll back CREATE USER statements. (Bug #28536312)
* Plugin variables with signed values were displayed
incorrectly. (Bug #28534414, Bug #92107)
* Mishandling of deprecated system variables could cause
output from queries on the Performance Schema
variables_by_thread table to be incorrect. (Bug
#28515475, Bug #92049)
* Data races discovered by Thread Sanitizer in
Event_queue::lock_data and the SAFE_MUTEX implementation
were fixed. (Bug #28510721, Bug #92041, Bug #28510691,
Bug #92040)
* No ER_NEED_REPREPARE diagnostic was pushed to the
diagnostics area when a reprepare failed for prepared
statements. (Bug #28509306, Bug #92029)
* When evaluating an expression using WITH ROLLUP, we now
write the result of the expression into a temporary table
only when it has a temporary table column. (Bug
#28493849, Bug #28523014)
* For debug builds, incorrect foreign key error checking
for ALTER TABLE on a TEMPORARY table could result in a
server exit. (Bug #28493257, Bug #91990)
* For some system variables, SET PERSIST persisted the
default value rather than the specified value. (Bug
#28466045)
* SET RESOURCE GROUP could not be executed as a prepared
statement. (Bug #28448258, Bug #91876)
* Restored a call to Item_field::fix_fields() that was
inadvertently removed during work done to implement
window functions. (Bug #28431783)
* Data races reported by Thread Sanitizer during X Plugin
startup and shutdown were corrected. (Bug #28407294)
* Creating a table with a partition description containing
illegal utf8 characters raised an assertion. (Bug
#28387488, Bug #91763)
* mysqldump output could include SQL mode values that have
been removed. (Bug #28373001, Bug #91714)
* A potential lock order cycle was corrected. (Bug
#28366531)
* On a GTID-enabled server, concurrent statements on the
INFORMATION_SCHEMA.COLUMNS table could deadlock. (Bug
#28293047, Bug #91548)
* CREATE TABLE statements for tables with the utf32 table
character set and literal strings in the table definition
raised an assertion. (Bug #28275881)
* Internal functions were added to support updating the
server version number upon the successful completion of a
server upgrade. (Bug #28211486)
* Comparing log file names as strings using the memcmp()
function resulted in uninitialized memory read errors.
The comparison now uses the strncmp() function. Thanks to
Zsolt Parragi and Laurynas Biveinis for their
contributions. (Bug #28178776, Bug #90238)
* On systems where Group Replication's Group Communication
System (GCS) used the systemd-resolved service for
network name resolution, if the host name could not be
resolved, GCS kept trying indefinitely. Now, if a retry
message is returned from any name resolution service, GCS
makes a limited number of retries, then concludes that
the host name is unresolvable. (Bug #28177861)
* The server mishandled stored program and resource group
names that differed only in accents. (Bug #28122841)
* The optimizer skipped the second column in a composite
index when executing an inner join with a LIKE clause
against the second column. (Bug #28086754)
* CREATE TABLE ... SELECT could create date columns with
"zero" date default values when it should have created
them without a default value. (Bug #28022129)
* The transformation of IN subquery predicates into
semijoins was not handled correctly for a very large
number of tables. (Bug #28004674)
* The bitmap used for reading fields from the storage
engine was not enabled correctly when performing the
filesort which is added to the last of any temporary
tables created for window functions. In the case where
there was no need for a temporary table, the server added
a filesort to the output from the select table, but the
removed reference (the WHERE condition) was not added.
Now in such cases, the reference is added to the select
table when the first window function needs sorting and no
temporary table was created before processing this window
function. (Bug #27975193)
* After seeing a row in the range frame, if another row was
later determined to be appearing before this range frame,
the server continued to check for new rows. This led to
the next frame calculation being done incorrectly. (Bug
#27973860)
* Server mishandling of SIGHUP signals could result in a
server exit. (Bug #27966483, Bug #90742)
* DELETE WHERE a=constant from a table with column a and
partitioned by the value of a generated column b led to
an assertion in debug builds. (Bug #27954073)
* INFORMATION_SCHEMA queries could cause a server exit when
updating dynamic table statistics. (Bug #27898108)
* A metadata locking deadlock could occur when opening a
foreign key parent table. (Bug #27859086)
* Improper memory handling by account management statements
could result in server misbehavior. (Bug #27820277)
* In certain cases, window functions did not handle ORDER
BY and PARTITION BY correctly. (Bug #27816506)
* The MySQL query optimizer identifies each predicate to be
pushed down to a table as a table condition; as part of
this process it checks to see whether a given predicate
among the table conditions is already known to be true in
virtue of the selected access path for the table, in
which case the predicate can safely be eliminated.
For example, when executing SELECT * FROM t1 WHERE pk=1,
where pk is the primary key of table t1, the ref access
method is selected. Since we know that this already
returns only rows for which pk=1, further evaluation of
this condition as a filter (Using where) should be
eliminated.
When optimizing a query which includes a GROUP BY or
ORDER BY, a late optimizer check is performed to discover
whether sorting can be skiped by using a sorted index
instead. Since this is done after another index may have
been chosen for accessing the table to be sorted, some
predicates thought to be redundant (due to the previous
access path selected) could be removed prematurely. To
compensate for this, the following actions were
performed:
+ Reconstruction of a table condition containing
predicates previously eliminated due to the access
method already being selected.
+ Performing a check to see whether any sorted index
existed such that sorting could be avoided, possibly
modifying the access plan.
Issues arose because the following actions also intended
to remedy early predicate removal were not performed
correctly:
+ Whether the access plan was modified or not, any
extra predicates added back in the reconstructed
table condition mentioned previously became a
permanent part of the table condition.
+ When the access plan was changed to use another
sorted index, no analysis was performed for the new
index in order to remove predicates made obsolete by
the new index.
A further problem existed for storage engines
implementing condition pushdown, such as NDBCLUSTER: The
conditions pushed down were generated from the table
condition prior to analysis, such that, if the access
path was later changed, the pushed condition did not
contain the predicates already removed, making condition
pushdown less efficient.
The root cause of this issue was that part_of_refkey()
analysis was performed on table predicates before the
access method for the table had been completely decided.
This is fixed by removing such early analysis. (Bug
#27808758, Bug #27814026)
* A windowing function that included an ORDER BY column
clause failed with Unknown field in window order by even
when the column was found in the table being queried.
(Bug #27808099)
* Executing a prepared statement to do a multiple-row
insert with large number of placeholders consumed
excessive memory and could execute slowly. (Bug
#27703912)
* On Windows, if the Visual C++ Redistributable for Visual
Studio had been removed, MySQL uninstallation using the
MSI installer failed. (Bug #27621546)
* The parser accepted invalid SET statement syntax in
trigger definitions that could result in a server exit.
(Bug #27595603)
* The server failed to start if the keyring_encrypted_file
plugin keyring file was invalid. (Bug #27588064)
* Keyring migration failed with source and destination
keyring plugins of keyring_okv and
keyring_encrypted_file, respectively. (Bug #27493970)
* It was possible in debug builds for a windowing function
using a signed integer to mishandle a frame that included
FOLLOWING. (Bug #27452365)
* When executing a prepared statement with a procedure call
with the CURSOR_TYPE_READ_ONLY flag set, the client
library hung if the procedure performed a SELECT that
returned an empty result set. (Bug #27443252, Bug #89214)
* Names of referenced columns of foreign keys were always
shown in lowercase in SHOW CREATE TABLE output and the
INFORMATION_SCHEMA.KEY_COLUMN_USAGE table. (Bug
#27353767, Bug #88718)
* Loading and unloading the audit_log plugin while
performing other concurrent activity could cause the
server to become unresponsive. (Bug #27325622)
* The data dictionary properties interface (dd::Properties)
and implementation was revised to provide a new method of
defining valid keys for property objects. (Bug #27309072,
Bug #89031, Bug #27309082, Bug #89032)
* Installing and uninstalling the validate_password
component concurrently with SET PASSWORD could cause
component failure. (Bug #27020979)
* Some typos in server source code were fixed. Thanks to
Hyunwoo Park for the contribution. (Bug #26189673, Bug
#86565)
* After column privileges were granted to a table, a
HANDLER READ call asserted during privilege checking.
(Bug #25987758)
* A check that ensures compatibility of referencing and
referenced column types in a foreign key definition was
moved from the storage engine layer to the SQL layer.
(Bug #25722927)
* The parser performed some out-of-memory checks
incorrectly. (Bug #25633994)
* When a subquery contained a UNION, the count of the
number of subquery columns was calculated incorrectly.
(Bug #24899924)
* A race condition between user-management statements and
other statements that tried to access grant tables
directly could result in deadlock and transaction
rollback. (Bug #24481240)
* When the server was started with the --skip-name-resolve
option, spurious warnings could be written to the error
log about ignoring accounts with a host name part of
localhost. (The accounts in fact were used and not
ignored.) (Bug #23329861, Bug #81441)
* DML statements using IGNORE were not always handled
correctly on tables having generated columns. (Bug
#22990029)
* MySQL now removes trivial WHERE conditions arising from
constant literal expressions during preparation, rather
than at a later stage in optimization. This should result
in improved plans for queries with outer joins containing
trivial conditions, such as this one:
SELECT * FROM t1 LEFT JOIN t2 ON condition_1 WHERE condition_2 OR 0 =
1
After removing the redundant OR 0 = 1 condition the
optimizer can rewrite the query as an inner join, as
shown here:
SELECT * FROM t1 LEFT JOIN t2 WHERE condition_1 AND condition_2
For more information, see What Is New in MySQL 8.0
(http://dev.mysql.com/doc/refman/8.0/en/mysql-nutshell.html),
and Outer Join Optimization
(http://dev.mysql.com/doc/refman/8.0/en/outer-join-optimization.html).
(Bug #16893426, Bug #28237111, Bug#28239008, Bug #28341790)
References: See also: Bug #28197977, Bug #28240054.
* Updates for BLOB columns in FEDERATED tables did not
work. (Bug #11748067, Bug #34997)
* Each of the functions REGEXP_REPLACE(), REGEXP_SUBSTR(),
REGEXP_LIKE(), and REGEXP_INSTR() returned a DOUBLE
instead of a value of the function's specified return
type. (Bug #90039, Bug #27682225)
* A query employing a dynamic range and an index merge
could use more memory than expected. (Bug #89953, Bug
#27659490)
* Selecting from a table having a CHAR column with a NO_PAD
collation yielded inconsistent results. (Bug #89753, Bug
#27578340)
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