Potential NullPointerException while obtaining row lock --------------------------------------------------------
Key: HBASE-5171 URL: https://issues.apache.org/jira/browse/HBASE-5171 Project: HBase Issue Type: Bug Components: regionserver Affects Versions: 0.90.5 Reporter: Yves Langisch We have a table which is concurrently accessed (read/write) from many threads and we make use of row locks. Under heavy load we regularly get NPE while obtaining row locks. An example stack trace looks as follows: java.lang.NullPointerException at org.apache.hadoop.hbase.regionserver.HRegionServer.convertThrowableToIOE(HRegionServer.java:986) at org.apache.hadoop.hbase.regionserver.HRegionServer.lockRow(HRegionServer.java:2008) at sun.reflect.GeneratedMethodAccessor20.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at org.apache.hadoop.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:570) at org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1039) Caused by: java.lang.NullPointerException at java.util.concurrent.ConcurrentHashMap.put(ConcurrentHashMap.java:881) at org.apache.hadoop.hbase.regionserver.HRegionServer.addRowLock(HRegionServer.java:2018) at org.apache.hadoop.hbase.regionserver.HRegionServer.lockRow(HRegionServer.java:2004) ... 5 more After checking the source code I've noticed that the value which is going to be put into the HashMap can be null in the case where the waitForLock flag is true or the rowLockWaitDuration is expired (HRegion#internalObtainRowLock, line 2111ff). The latter I think happens in our case as we have heavy load hitting the server. IMHO this case should be handled somehow and must not lead to a NPE. - Yves -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa For more information on JIRA, see: http://www.atlassian.com/software/jira