[HBASE-19995] Current Jetty 9 version in HBase master branch can memory leak under high traffic

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.0.0
• Component/s: REST

Environment

Closing this ticket, Jetty was later upgraded in HBASE-21282

• Assignee: Unassigned
• Reporter: Ben Lau
• Created: 13/Feb/18 23:28
• Updated: 27/Mar/19 21:21
• Resolved: 27/Mar/19 21:21

Description

There is a memory-leak in Jetty 9 that manifests whenever you hit the call queue limit in HBase REST.  The memory-leak leaks both on-heap and off-heap objects permanently.  It happens because whenever the call queue for Jetty server overflows, the task that is rejected runs a 'reject' method if it is a Rejectable to do any cleanup. This clean up is necessary to for example close the connection, deallocate any buffers, etc. Unfortunately, in Jetty 9, they implemented the 'reject' / cleanup method of the SelectChannelEndpoint as a non-blocking call that is not guaranteed to run.  This was later fixed in Jetty 9.4 and later backported however the version of Jetty 9 pulled in HBase for REST comes before this fix.  See https://github.com/eclipse/jetty.project/issues/1804 and https://github.com/apache/hbase/blob/master/pom.xml#L1416.

If we want to stay on 9.3.X we could update to 9.3.22.v20171030 which is the latest version of 9.3.  Thoughts?