Debezium Blog

I’m delighted to announce the release of Debezium 0.9 Final!

This release only adds a small number of changes since last week’s CR1 release; most prominently there’s some more metrics for the SQL Server connector (lag behind master, number of transactions etc.) and two bug fixes related to the handling of partitioned tables in MySQL (DBZ-1113) and Postgres (DBZ-1118).

Having been in the works for six months after the initial Alpha release, Debezium 0.9 comes with a brand new connector for SQL Server, lots of new features and improvements for the existing connectors, updates to the latest versions of Apache Kafka and the supported databases as well as a wide range of bug fixes.

Reaching the home stretch towards Debezium 0.9, it’s with great pleasure that I’m announcing the first release of Debezium in 2019, 0.9.0.CR1!

For this release we’ve mainly focused on sorting out remaining issues in the Debezium connector for SQL Server; the connector comes with greatly improved performance and has received a fair number of bug fixes.

Other changes include a new interface for event handlers of Debezium’s embedded engine, which allows for bulk handling of change events, an option to export the scale of numeric columns as schema parameter, as well as a wide range of bug fixes for the Debezium connectors for MySQL, Postgres and Oracle.

With only a few days left for the year, it’s about time for another Debezium release; so it’s with great pleasure that I’m announcing Debezium 0.9.0.Beta2!

This release comes with support for MySQL 8 and Oracle 11g; it includes a first cut of metrics for monitoring the SQL Server and Oracle connectors, several improvements to the MongoDB event flattening SMT as well as a wide range of bug fixes. Overall, not less than 42 issues were addressed; very clearly, there has to be some deeper sense in that ;)

A big shout out goes to the following members Debezium’s amazing community, who contributed to this release: Eero Koplimets, Grzegorz Kołakowski, Hanlin Liu, Lao Mei, Renato Mefi, Tautvydas Januskevicius, Wout Scheepers and Zheng Wang!

In the following, let’s take a closer look at some of the changes coming with the 0.9 Beta2 release.

The second-level cache of Hibernate ORM / JPA is a proven and efficient way to increase application performance: caching read-only or rarely modified entities avoids roundtrips to the database, resulting in improved response times of the application.

Unlike the first-level cache, the second-level cache is associated with the session factory (or entity manager factory in JPA terms), so its contents are shared across transactions and concurrent sessions. Naturally, if a cached entity gets modified, the corresponding cache entry must be updated (or purged from the cache), too. As long as the data changes are done through Hibernate ORM, this is nothing to worry about: the ORM will update the cache automatically.

Things get tricky, though, when bypassing the application, e.g. when modifying records directly in the database. Hibernate ORM then has no way of knowing that the cached data has become stale, and it’s necessary to invalidate the affected items explicitly. A common way for doing so is to foresee some admin functionality that allows to clear an application’s caches. For this to work, it’s vital to not forget about calling that invalidation functionality, or the application will keep working with outdated cached data.

In the following we’re going to explore an alternative approach for cache invalidation, which works in a reliable and fully automated way: by employing Debezium and its change data capture (CDC) capabilities, you can track data changes in the database itself and react to any applied change. This allows to invalidate affected cache entries in near-realtime, without the risk of stale data due to missed changes. If an entry has been evicted from the cache, Hibernate ORM will load the latest version of the entity from the database the next time is requested.

It’s my pleasure to announce the release of Debezium 0.9.0.Beta1! Oh, and to those of you who are celebrating it — Happy Thanksgiving!

This new Debezium release comes with several great improvements to our work-in-progress SQL Server connector: