[HBASE-818] Deadlock running 'flushSomeRegions'

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.2.0
• Fix Version/s: 0.2.1, 0.18.0
• Assignee: Andrew Kyle Purtell
• Reporter: Michael Stack
• Created: 11/Aug/08 23:53
• Updated: 13/Sep/08 23:22
• Resolved: 12/Aug/08 16:22

Description

Playing with MR uploading no a regionserver with 60+ regions, I ran into a deadlock:

Found one Java-level deadlock:
=============================
"IPC Server handler 19 on 60020":
  waiting to lock monitor 0x084be38c (object 0xb6f69a70, a org.apache.hadoop.hbase.regionserver.Flusher),
  which is held by "IPC Server handler 16 on 60020"
"IPC Server handler 16 on 60020":
  waiting to lock monitor 0x080f8dec (object 0xb73610c0, a org.apache.hadoop.hbase.regionserver.HRegion$WriteState),
  which is held by "IPC Server handler 2 on 60020"
"IPC Server handler 2 on 60020":
  waiting to lock monitor 0x086e8fe8 (object 0xb6f69cf0, a java.util.HashSet),
  which is held by "IPC Server handler 16 on 60020"

Java stack information for the threads listed above:
===================================================
"IPC Server handler 19 on 60020":
        at org.apache.hadoop.hbase.regionserver.Flusher.flushSomeRegions(Flusher.java:261)
        - waiting to lock <0xb6f69a70> (a org.apache.hadoop.hbase.regionserver.Flusher)
        at org.apache.hadoop.hbase.regionserver.Flusher.reclaimMemcacheMemory(Flusher.java:252)
        at org.apache.hadoop.hbase.regionserver.HRegionServer.batchUpdate(HRegionServer.java:1136)
        at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:623)
        at org.apache.hadoop.hbase.ipc.HbaseRPC$Server.call(HbaseRPC.java:473)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:896)
"IPC Server handler 16 on 60020":
        at org.apache.hadoop.hbase.regionserver.HRegion.flushcache(HRegion.java:948)
        - waiting to lock <0xb73610c0> (a org.apache.hadoop.hbase.regionserver.HRegion$WriteState)
        at org.apache.hadoop.hbase.regionserver.Flusher.flushRegion(Flusher.java:173)
        - locked <0xb6f69cf0> (a java.util.HashSet)
        at org.apache.hadoop.hbase.regionserver.Flusher.flushSomeRegions(Flusher.java:267)
        - locked <0xb6f69a70> (a org.apache.hadoop.hbase.regionserver.Flusher)
        at org.apache.hadoop.hbase.regionserver.Flusher.reclaimMemcacheMemory(Flusher.java:252)
        at org.apache.hadoop.hbase.regionserver.HRegionServer.batchUpdate(HRegionServer.java:1136)
        at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:623)
        at org.apache.hadoop.hbase.ipc.HbaseRPC$Server.call(HbaseRPC.java:473)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:896)
"IPC Server handler 2 on 60020":
        at org.apache.hadoop.hbase.regionserver.Flusher.addRegion(Flusher.java:237)
        - waiting to lock <0xb6f69cf0> (a java.util.HashSet)
        at org.apache.hadoop.hbase.regionserver.Flusher.request(Flusher.java:114)
        at org.apache.hadoop.hbase.regionserver.HRegion.requestFlush(HRegion.java:1627)
        - locked <0xb73610c0> (a org.apache.hadoop.hbase.regionserver.HRegion$WriteState)
        at org.apache.hadoop.hbase.regionserver.HRegion.update(HRegion.java:1614)
        at org.apache.hadoop.hbase.regionserver.HRegion.batchUpdate(HRegion.java:1398)
        at org.apache.hadoop.hbase.regionserver.HRegionServer.batchUpdate(HRegionServer.java:1137)
        at sun.reflect.GeneratedMethodAccessor3.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:623)
        at org.apache.hadoop.hbase.ipc.HbaseRPC$Server.call(HbaseRPC.java:473)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:896)

Found 1 deadlock.

Regionserver is hosed.