MySQL 5.7 Release Notes
• 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: 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: 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: 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: 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: 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)
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