I’m pleased to announce the newest MySQL Connector/J 5.1 Maintenance Release.

As usual, MySQL Connector/J 5.1 can be downloaded from the official distribution channels MySQL Downloads and The Central Repository. The commercially licensed version is available for download at My Oracle Support.

Please don’t forget to consult the CHANGES file in the download archive and/or the release notes page to know what is new and if there are any changes that might affect your applications.

MySQL Connector/J 5.1.40 is the official JDBC driver for MySQL databases and, as such, we are continuously working to make it better, more reliable and faster. This new version delivers several bug fixes and upgrades. This is the current recommend  version and you should upgrade to it as soon as possible.

I’d like to highlight the most relevant fixes and improvements in this release:

Recovered & new features

Previous versions used to silently disable local transaction states management (connection property useLocalTransactionState=true) when server side query cache was enable. This used to be workaround for a know server bug that it’s long time gone. The workaround in Connector/J side, though, survived till these days. I’m pretty sure that the effects will be almost unnoticed but certainly this helps empowering the developer and provides better control over the Connector.

The XA errors mapping in Connector/J was updated with the missing error codes that the server may throw back.

MySQL Fabric support issues

Connector/J 5.1 maintains support for MySQL Fabric, as such, this release comes with a couple fixes to it. Fabric connections are especially prone to problems as they rely on both a connection to a Fabric node and multiple connections to MySQL servers while having to be able to refresh themselves to topology changes, failures and such. A couple of issues caused by communication failures to the Fabric node are now fixed.

Continuous improvement of MySQL data types support

The JSON data type is relatively new in Connector/J. As such, every now and then there is something that needs to be fixed or adjusted. This time it was an encoding issue observed when the JSON strings contained non Latin characters. Additionally, the specific combination of updatable result sets with cursor based fetches was missing the support for the JSON type.

Getting data from BIT columns as numeric values was behaving inconsistently when binary values and ASCII values of numbers matched. As a result, instead of the expected value, it was occurring an extra conversion to String before the data was returned. Also fixed in this release.

Improved internals

Although we aim to, it’s almost impossible to guarantee that the code is free from memory leaks, deadlocks, NPEs and so on. A few of those where caused by some bugs that are now fixed.

Under certain situations the exception interceptor mechanism was being triggered twice. This, not only caused an unwanted additional  processing, but also was hiding the real cause that triggered the interceptor.

Client-side caching of prepared statements while using server-side prepared statements requires extra care because it can easily be a source of memory leaks, both on client and server sides. In this particular scenario, setting a statement as non-poolable was causing a never ending number of prepared statements on server and never deallocated. Per se, this wasn’t a problem for the driver because it is prepared to switch-over to client prepared statements as soon as it is unable to create more on the server, but it wasn’t the desired behavior for sure.

Transactions states managed locally got fixed for when there were exceptions while on the middle of one. Without the fix the rollback and commit wasn’t operating as expected.

The database connection URL syntax got support for several extensions over the year. With that also increased the corner cases that its parsers have to deal with. A couple of them were fixed in this release, specifically a NPE and an incompatibility with host names starting with the word “address”.

Thanks!

Enjoy this new Connector/J release. Get the most out of it by reading its official documentation or by getting the developer’s support directly from the forum channel.

Special thanks to Dong Song Ling and Ryosuke Yamazaki for their valuable contributions.

Thank you all for your support and feedback, and keep in touch!

On behalf of the MySQL Connector/J Team