Today we are pleased to announce the release of Elasticsearch 5.2.1, based on Lucene 6.4.1. It is already available for deployment on Elastic Cloud, our Elasticsearch-as-a-service platform. All users should upgrade.
Latest stable release in 5.x:
Most of the bug fixes in this release are fairly minor, but Lucene 6.4.1 has fixes for two important memory leaks:
When stored fields are configured with
best_compression, we rely on JVM garbage collection to reclaim Deflater/Inflater instances. However these classes use little JVM memory but may use significant native memory, so if may happen that the OS runs out of native memory before the JVM collects these unreachable Deflater/Inflater instances. Fixed by LUCENE-7647.
- Certain queries can hold a reference to the IndexReader that was used to build them. When these queries are cached, this reference causes Lucene to hold onto segments long after they should have been deleted. Fixed by LUCENE-7657.