NOTE: You are looking at documentation for an older release. For the latest information, see the current release documentation.
Slow loggers can cause Log4j loggers to leak over time. When a new index is created, a new Log4j logger is associated with it. However, when an index is deleted, Log4j keeps an internal reference to its loggers that results in a memory leak #57228 (issue: #56171)
This issue is fixed in Elasticsearch 6.8.10 and 7.7.1.
Also see Breaking changes in 6.8.