[jira] [Created] (HBASE-13068) Unexpected client exception with slow scan

["Lars Hofhansl (JIRA)" <ji...@apache.org>]

Lars Hofhansl created HBASE-13068:
-------------------------------------

             Summary: Unexpected client exception with slow scan
                 Key: HBASE-13068
                 URL: https://issues.apache.org/jira/browse/HBASE-13068
             Project: HBase
          Issue Type: Bug
            Reporter: Lars Hofhansl


I just came across in interesting exception:
{code}
Caused by: java.io.IOException: Call 10 not added as the connection newbunny/127.0.0.1:60020/ClientService/lars (auth:SIMPLE)/60000 is closing
        at org.apache.hadoop.hbase.ipc.RpcClient$Connection.addCall(RpcClient.java:495)
        at org.apache.hadoop.hbase.ipc.RpcClient.getConnection(RpcClient.java:1534)
        at org.apache.hadoop.hbase.ipc.RpcClient.call(RpcClient.java:1442)
        ... 13 more
{code}

Called from here:
{code}
        at org.apache.hadoop.hbase.client.ScannerCallable.close(ScannerCallable.java:291)
        at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:160)
        at org.apache.hadoop.hbase.client.ScannerCallable.call(ScannerCallable.java:59)
        at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:115)
        at org.apache.hadoop.hbase.client.RpcRetryingCaller.callWithRetries(RpcRetryingCaller.java:91)
        at org.apache.hadoop.hbase.client.ClientScanner.nextScanner(ClientScanner.java:247)
{code}

This happened when I scanned with multiple client against a single region server when all data is filtered at the server by a filter.
I had 10 clients, the region server has 30 handles.

This means the scanners are not getting closed and their lease has to expire.

The workaround is to increase hbase.ipc.client.connection.maxidletime.
But it's strange that this *only* happens at close time. And since I am not using up all handlers there shouldn't be any starvation.



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