[HBASE-3654] Weird blocking between getOnlineRegion and createRegionLoad

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.90.1
• Fix Version/s: 0.90.2
• Hadoop Flags: Reviewed
• Assignee: Subbu M Iyer
• Reporter: Jean-Daniel Cryans
• Created: 16/Mar/11 04:09
• Updated: 20/Nov/15 12:43
• Resolved: 24/Mar/11 20:26

Description

Saw this when debugging something else:

"regionserver60020" prio=10 tid=0x00007f538c1c0000 nid=0x4c7 runnable [0x00007f53931da000]
   java.lang.Thread.State: RUNNABLE
	at org.apache.hadoop.hbase.regionserver.Store.getStorefilesIndexSize(Store.java:1380)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.createRegionLoad(HRegionServer.java:916)
	- locked <0x0000000672aa0a00> (a java.util.concurrent.ConcurrentSkipListMap)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.buildServerLoad(HRegionServer.java:767)
	- locked <0x0000000656f62710> (a java.util.HashMap)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.tryRegionServerReport(HRegionServer.java:722)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.run(HRegionServer.java:591)
	at java.lang.Thread.run(Thread.java:662)

"IPC Reader 9 on port 60020" prio=10 tid=0x00007f538c1be000 nid=0x4c6 waiting for monitor entry [0x00007f53932db000]
   java.lang.Thread.State: BLOCKED (on object monitor)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.getFromOnlineRegions(HRegionServer.java:2295)
	- waiting to lock <0x0000000656f62710> (a java.util.HashMap)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.getOnlineRegion(HRegionServer.java:2307)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.getRegion(HRegionServer.java:2333)
	at org.apache.hadoop.hbase.regionserver.HRegionServer$QosFunction.isMetaRegion(HRegionServer.java:379)
	at org.apache.hadoop.hbase.regionserver.HRegionServer$QosFunction.apply(HRegionServer.java:422)
	at org.apache.hadoop.hbase.regionserver.HRegionServer$QosFunction.apply(HRegionServer.java:361)
	at org.apache.hadoop.hbase.ipc.HBaseServer.getQosLevel(HBaseServer.java:1126)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Connection.processData(HBaseServer.java:982)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Connection.readAndProcess(HBaseServer.java:946)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:522)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:316)
	- locked <0x0000000656e60068> (a org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)
...

"IPC Reader 0 on port 60020" prio=10 tid=0x00007f538c08b000 nid=0x4bd waiting for monitor entry [0x00007f5393be4000]
   java.lang.Thread.State: BLOCKED (on object monitor)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.getFromOnlineRegions(HRegionServer.java:2295)
	- waiting to lock <0x0000000656f62710> (a java.util.HashMap)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.getOnlineRegion(HRegionServer.java:2307)
	at org.apache.hadoop.hbase.regionserver.HRegionServer.getRegion(HRegionServer.java:2333)
	at org.apache.hadoop.hbase.regionserver.HRegionServer$QosFunction.isMetaRegion(HRegionServer.java:379)
	at org.apache.hadoop.hbase.regionserver.HRegionServer$QosFunction.apply(HRegionServer.java:422)
	at org.apache.hadoop.hbase.regionserver.HRegionServer$QosFunction.apply(HRegionServer.java:361)
	at org.apache.hadoop.hbase.ipc.HBaseServer.getQosLevel(HBaseServer.java:1126)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Connection.processData(HBaseServer.java:982)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Connection.readAndProcess(HBaseServer.java:946)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Listener.doRead(HBaseServer.java:522)
	at org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader.run(HBaseServer.java:316)
	- locked <0x0000000656e635c8> (a org.apache.hadoop.hbase.ipc.HBaseServer$Listener$Reader)
	at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
	at java.lang.Thread.run(Thread.java:662)

All the readers are blocked! I have the feeling something much better could be done.