[TEZ-4080] TezClient should close FileSystem objects to prevent leak

• Type: Bug
• Status: Patch Available
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 0.9.1
• Assignee: Unassigned
• Reporter: Zoltan Haindrich
• Created: 24/Jul/19 14:15
• Updated: 18/Nov/19 19:43

Description

When opening/closing a lot of tez clients; some FileSystem object references are retained even after the client is closed - due to the fact the FileSystem has a "cache" which collects all open FileSystem objects - to be able to close all of them from a single shutdownhook.

Not closing these FileSystem objects causes them to pile up in the "cache" which has hard references to them
In a simple hive test which was run with 150M of memory; these "lost" filesystem objects could result in an OOM after ~170 sessions.

A sample creation stack trace of a FileSystem object:

        at org.apache.hadoop.hive.ql.io.ProxyLocalFileSystem.<init>(ProxyLocalFileSystem.java:49)
        at sun.reflect.GeneratedConstructorAccessor83.newInstance(Unknown Source)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.apache.hadoop.util.ReflectionUtils.newInstance(ReflectionUtils.java:133)
        at org.apache.hadoop.fs.FileSystem.createFileSystem(FileSystem.java:3353)
        at org.apache.hadoop.fs.FileSystem.access$200(FileSystem.java:124)
        at org.apache.hadoop.fs.FileSystem$Cache.getInternal(FileSystem.java:3403)
        at org.apache.hadoop.fs.FileSystem$Cache.get(FileSystem.java:3371)
        at org.apache.hadoop.fs.FileSystem.get(FileSystem.java:477)
        at org.apache.hadoop.fs.Path.getFileSystem(Path.java:361)
        at org.apache.tez.dag.app.DAGAppMaster.serviceInit(DAGAppMaster.java:502)
        at org.apache.hadoop.service.AbstractService.init(AbstractService.java:164)
        at org.apache.tez.dag.app.DAGAppMaster$9.run(DAGAppMaster.java:2663)

Issue Links

• is related to: HIVE-22038 Fix memory related sideeffects of opening/closing sessions