Hazelcast IMDG 4.2 GA is Released!

Jiri Holusa | Mar 24, 2021

It’s a pleasure to announce the general availability of Hazelcast IMDG 4.2!

In this blog post, we highlight the most notable features and enhancements in this release. We resolved almost 150 GitHub issues and merged roughly 350 pull requests and you can find the complete list of changes in the release notes. Don’t hesitate to download it and get started.

Shoutout to Community

Accepting contributions from the community is one of the many pleasures of being an open source company. Big thanks to those who contributed to IMDG 4.2. A complete list of contributors can be found in the release notes.

More SQL

In Hazelcast IMDG 4.1, we delivered the initial support for SQL and reaffirmed our commitment to continue on SQL. We’re fulfilling that promise in 4.2 as the SQL query engine has gained new capabilities and enhancements, most noticeably:

  • Support for sorting using the `ORDER BY` clause
  • Ability to work with temporal types such as dates and time
  • Handful of improvements around expressions, such as `NOT LIKE`, `MOD`, named parameters and `LIKE` supporting indexes
  • Performance improvements

We’ve made a big leap with SQL and we are dedicated to its continued evolution. Give the new SQL engine a try.

New Documentation Portal

User-friendly documentation is the centerpiece of a good user experience. While there’s hardly someone who would disagree, it’s always a tough decision to spend development time on documentation rather than new shiny features.

We invested heavily in the new documentation portal which is available at an easy-to-remember URL, docs.hazelcast.com. This portal now serves as a landing page for all the documentation to all Hazelcast projects with new looks, new search and other tweaks like quick bug fix submission. Make sure to check it out.

AWS Partition Placement Group Aware Deployments 

When running the Hazelcast IMDG cluster in AWS EC2, one of the best practices to provide the best performance is to put the members into the same placement group. 

Hazelcast IMDG newly provides the out-of-the-box PLACEMENT_AWARE partition group strategy which respects the placement groups. This grouping provides a finer granularity than ZONE_AWARE and is useful for good redundancy when running members within a single availability zone; it provides availability within a single zone as high as possible by spreading the partitions and their replicas across different racks. 

Reducing HD Memory Overhead (Enterprise Edition)

One of the key features of the Enterprise Edition is to store the data off-heap in the High-Density (HD) Memory Store to deliver improved performance even with large data volumes that are beyond the powers of garbage collectors.

The HD storage has been enhanced to cut the overhead per each entry. As a result, with IMDG 4.2 you should be able to store more data within the same memory space making your deployments more efficient, e.g. for 100 bytes values, you’ll now save up to 30% of your memory.

Dynamic Log Level Change

When things go wrong, enabling more fine-grained logging is often the only chance to find out the root cause. To make the Operations experience more convenient, we implemented a small, yet useful enhancement to change the log level at runtime without restarting the member. 

Closing Words

We’re seeking your feedback. Don’t hesitate to reach out via Slack, Google Groups or Twitter. If you’re interested in the feature design details, we have also published new design documents on GitHub. Check them out!

Happy Hazelcasting!


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About the Author

Jiri Holusa

Product Manager, Platform

Jiri is a devoted open source software engineer that loves his work. Born in Red Hat and later Hazelcast as a Quality Engineer, he is now the Product Manager of Hazelcast IMDG. Digging deep and never giving up on a problem until it’s solved and enjoying this all the way, that’s Jiri. Besides that, he loves basically any sport and as a true Czech person, he never refuses a pleasant conversation over a pint of beer.

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