[HBASE-25307] ThreadLocal pooling leads to NullPointerException

• Type: Bug
• Status: Resolved
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.0-alpha-1
• Fix Version/s: 3.0.0-alpha-1, 2.4.0, 2.2.7, 2.3.4
• Component/s: Client
• Assignee: Balazs Meszaros
• Reporter: Balazs Meszaros
• Created: 19/Nov/20 11:14
• Updated: 01/Dec/20 18:10
• Resolved: 30/Nov/20 12:04

Description

We got NPE after setting hbase.client.ipc.pool.type to thread-local:

20/11/18 01:53:04 ERROR yarn.ApplicationMaster: User class threw exception: java.lang.NullPointerException
java.lang.NullPointerException
        at org.apache.hadoop.hbase.ipc.AbstractRpcClient.close(AbstractRpcClient.java:496)
        at org.apache.hadoop.hbase.client.ConnectionImplementation.close(ConnectionImplementation.java:1944)
        at org.apache.hadoop.hbase.mapreduce.TableInputFormatBase.close(TableInputFormatBase.java:660)

The root cause of the issue is probably at PoolMap.ThreadLocalPool.values():

public Collection<R> values() {
  List<R> values = new ArrayList<>();
  values.add(get());
  return values;
}

It adds null into the collection if the current thread does not have any resources which leads to NPE later.

I traced the usages of values() and it should return every resource, not just that one which is attached to the caller thread.

Issue Links

• links to: GitHub Pull Request #2685
• links to: GitHub Pull Request #2709