MySQL Connector/J 5.1.40 has been released

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

MySQL Connector/J 5.1.39 has been released

I’m pleased to announce that MySQL Connector/J 5.1.39 Maintenance Release is now generally available.

MySQL Connector/J 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.

As always, we recommend that you check 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.

With MySQL Connector/J 5.1.39 you get the continuously improved JDBC driver for MySQL databases, now including several fixes and upgrades. Even if you didn’t face any of the fixed issues, we do recommend that you upgrade to the latest version.

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

MySQL Fabric support related issues

As you well know by now, MySQL Fabric support in Connector/J is built on its generic multi-host connections feature, more specifically on replication connections. This feature, along with load-balanced connections support, have received several improvements all over the latest releases. This time, we fixed and tuned up a few incoherences that were spotted on a few corner cases, namely when, due to the Fabric management process, the list of known hosts in an active connection could actually become empty for a short period of time while performing the fail-over, and so causing a whole set of new problems. As a consequence of these developments, we introduced a new connection property:

loadBalanceHostRemovalGracePeriod. This property sets the time, in milliseconds, that the driver should wait for a load-balanced connection to be allowed to switch to a different host when the currently active one is being removed, either by an internal process such as in a Fabric or a replication connection, or by dynamic hosts management, through the JMX interfaces the driver provides. Default value is 15000 milliseconds.

Additional improvements and fixes

  • Unnecessary exception throwing and capturing when establishing connections.
  • Temporal data corruption in prepared statements under special circumstances.
  • Incorrect JDBC 4.2 Java 8 Time support when using cached prepared statements.
  • Application server using multiple class loaders could face a NullPointerException when setting up the driver’s time zone configurations.
  • Exception caused by missing metadata information in updatable result sets.
  • Concurrent modification issue on closing statements and connections concurrently from different threads.
  • Maintenance fixes in the test suite.
  • Source code formatting, Copyright notice fixes.
  • Build script adjustments, new code coverage reports, compiler warnings cleanup.
  • Manifest fixed to expose Fabric connections.
  • Support for latest changes in MySQL protocol, introduced in MySQL 5.7, namely the deprecation of EOF packets.

Thanks!

Enjoy this new release of Connector/J and stay tuned for the next releases as there is still much to deliver.

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

Thank you all for your support and keep in touch!

On behalf of the MySQL Connector/J Team

MySQL Connector/J 5.1.38 has been released

I’m pleased to announce that MySQL Connector/J 5.1.38 Maintenance Release is now generally available.

MySQL Connector/J 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.

As always, we recommend that you check the CHANGES file in the download archive and/or the release notes to be aware of changes in behavior that might affect your application.

MySQL Connector/J 5.1.38, although released shortly after its predecessor, includes several important fixes and improvements. Most of them related to MySQL Fabric, multi-host replication aware connections support and support for TLSv1.2 and new encryption defaults. Even if you don’t require such features, we do recommend the upgrade to the latest version.

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

MySQL Fabric and Multi-Host Replication Connections Revision

MySQL Fabric support in Connector/J is based on multi-host replication aware connections and the ability to dynamically manage server groups. Most of the server groups management is done automatically and, possibly, concurrently. The combination of all these features was never thoroughly used and stressed as much as now and the consequence is that they were effectively in need of some improvements.

This release ships with a fully re-factored multi-host replication aware connections support, which now inherits from the same base architecture as the remaining multi-host connections alternatives, the fail-over connections and load-balanced connections. This architecture provides a layered connection support structure and an improved statement execution routing model that effectively determines the correct physical connection to use at execution time, also fixing, by this way, a couple of existing bugs. The synchronization model in the server groups management was revised as well in order to overcome a few known thread deadlock situations. As a direct result the fail-over in MySQL Fabric support is now way more robust.

In the process of the improvements made in multi-host replication aware connections, two new connection properties were added:

allowSlaveDownConnections. This property sets the behavior for establishing replication aware connections when no slave hosts available. While, previously, this would result in a failed connection attempt, now we can define the behavior we prefer. This property takes a boolean value:

readFromMasterWhenNoSlaves. This property sets the behavior for the situations where, at run-time, all slave hosts in a replication aware connection become unavailable. The alternatives “should it fail?”, the only possible outcome before introducing this property, or “should the master host(s) be used in their place?”, are now available to the developer. Mind that when you set the option to use the master host(s), they will be used in read-only state as if they were slave hosts. Also mind that setting this property to true might, transparently, incur in extra load to the master host(s). This property takes a boolean value:

Security Compliance and Improvements

In its way of complying with the up-to-date security regulations and requirements, MySQL server 5.7 is now shipped with SSL/TLS enabled by default and any clients connecting to it should make use of such data protection features by default as well. Following this path, Connector/J 5.1.38 prioritizes the usage of SSL/TLS when establishing connections to this server. The missing support for TLSv1.2 and TLSv1.1 was additionally included in this release.

Connector/J now attempts to use the highest security layer available at run-time, starting from TLSv1.2 and, at the end, providing the best encryption system possible for the moment. This obviously depends on the MySQL server version we are connecting to and on the JVM version in use. In some situations it may be somewhat complex to find a compatible set of cyphers that can be used in both ends and some tweaks or adjustments could be required. The connection property enabledSSLCipherSuites may be a good companion in such cases.

Additional Bug Fixes

This release also includes a few other minor bug fixes. Although not especially relevant, these fixes help improving the overall quality of this Connector/J release.

Thanks!

Thank you all for your support. Enjoy this new Connector/J and keep in touch!

On behalf of the MySQL Connector/J Team.