MySQL 5.6.23 was recently released (it is the latest MySQL 5.6, is GA), and is available for download here.
For this release, there is 1 “Security Note”, 3 “Functionality Changed”, and 5 “Compilation Notes”, all benign, but let me address them:
- Security Note: The linked OpenSSL library for the MySQL Commercial Server has been updated from version 1.0.1j to version 1.0.1k. Issues fixed in the new version are described at http://www.openssl.org/news/vulnerabilities.html.
- Functionality Changed: Support for the SSL 2.0 and SSL 3.0 protocols has been disabled because they provide weak encryption. (Bug #19820550, Bug #19921150)
- Functionality Changed: yaSSL was upgraded to version 2.3.7. (Bug #19695101, Bug #20201864)
- Functionality Changed: The valid date range of the SSL certificates in mysql-test/std_data has been extended to the year 2029. (Bug #18366947)
In addition to those, there were 37 other bug fixes:
- 13 InnoDB
- 5 Replication
- 18 Miscellaneous
- 1 Partitioning
The highlights for me are the Partitioning bug, 1 of the Replication bugs, and 8 of the InnoDB bugs, as 1 was a regression bug (crashing/corruption) and the others include bugs that raise invalid assertions, server halts, break replication, and so forth, though all in all, I wouldn’t say any of these are very common and require immediate attention:
- InnoDB: If a DROP DATABASE statement failed on the master, mismatched tables could be left on the slave, breaking replication. This was caused by the DROP TABLE statement being binary logged if at least one table was deleted during the DROP DATABASE operation. The fix ensures that in such a situation the DROP TABLE statement is binary logged with the IF EXISTS option. (Bug #74890, Bug #20041860)
- InnoDB: A tablespace export operation set the purge state to PURGE_STATE_STOP but the purge thread did not check the purge state until the current purge operation was completed. In the case of a large history list, the tablespace export operation was delayed, waiting for the current purge operation to finish. The purge state is now checked with every purge batch. (Bug #20266847, Bug #75298)
- InnoDB: An ALTER TABLE … ADD INDEX operation raised an assertion due to assertion code that did not allow an online index status of ONLINE_INDEX_ABORTED_DROPPED. The assertion code has been relaxed. (Bug #20198726)
- InnoDB: DML operations on a table with full-text search indexes raised an invalid assertion. (Bug #19905246) References: This bug is a regression of Bug #19314480.
- InnoDB: A multiple-table delete operation caused the server to halt. (Bug #19815702)
- InnoDB: A FLUSH TABLES operation raised an assertion. (Bug #19803418)
- InnoDB: With change buffering enabled, a buffered sequence of operations that should not have been buffered resulted in an Unable to purge a record error. (Bug #19528825, Bug #73767)
- InnoDB: A slow shutdown (innodb_fast_shutdown=0) after crash recovery raised an assertion. Slow shutdown did not wait for background rollback operations to finish before proceeding. (Bug #16862810)
- Partitioning: A failed ALTER TABLE … TRUNCATE PARTITION statement or a failed TRUNCATE TABLE statement against a partitioned table sometimes left inconsistent metadata in the table cache; subsequent SQL statements reusing this metadata failed, and could in some cases also lead to a failure of the server. (Bug #74292, Bug #19786861)
- Replication: When using SHOW SLAVE STATUS to monitor replication performance, Seconds_Behind_Master sometimes displayed unexpected lag behind the master. This was caused by Previous_gtids log events being written to the slave’s relay log with a timestamp behind the master, and then being used to calculate the Seconds_Behind_Master. This fix ensures that events generated on the slave that are added to the relay log and are not used when calculating Seconds_Behind_Master. (Bug #72376, Bug #18622657)
So while there were no major changes, those 8 InnoDB bugs, especially in total, are of concern, so I’d consider upgrading if I were running InnoDB on a prior version of 5.6.
And with the yaSSL updates, if you use SSL connections, you may want to consider upgrading as well.
The full 5.6.23 changelogs can be viewed here (which has more details about all of the bugs listed above):
Hope this helps.