[HBASE-790] During import, single region blocks requests for >10 minutes, thread dumps, throws out pending requests, and continues

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Fixed
• Affects Version/s: 0.2.0
• Fix Version/s: 0.2.0
• Component/s: regionserver

Environment

11 node cluster. 1 master w/ namenodes and hmaster. 10 slaves w/ datanodes and regionservers. All are 2GHz quad core xeons, 4gb ram, raid 0.

• Assignee: Andrew Kyle Purtell
• Reporter: Jonathan Gray
• Created: 01/Aug/08 00:38
• Updated: 22/Aug/08 21:13
• Resolved: 05/Aug/08 19:06

Description

During a batch import, I have two processes importing into a single region.

The behavior I saw was a regionserver with 2 regions of the table in question on it. The first region split, and the new regions were reassigned to another regionserver.

Following that, inserting into the region that was left over began to block client requests. I am attaching the regionserver log; below is the specific problem area:

2008-07-31 15:38:24,190 DEBUG org.apache.hadoop.hbase.client.HConnectionManager$TableServers: Cache hit in table locations for row <> and tableName .META.: location server 72.34.249.217:60020, location region name .META.,,1
2008-07-31 15:38:24,194 INFO org.apache.hadoop.hbase.regionserver.CompactSplitThread: region split, META updated, and report to master all successful. Old region=REGION => {NAME => 'items,01beddd6-813b-4f2b-ac48-a0cef395cb7e,12175434512
2008-07-31 15:38:34,052 INFO org.apache.hadoop.hbase.regionserver.HRegion: Blocking updates for 'IPC Server handler 7 on 60020' on region items,8001eb31-98bb-4087-bd8d-e4b42805addb,1217543451296: Memcache size 64.0m is >= than blocking
2008-07-31 15:39:00,270 INFO org.apache.hadoop.ipc.Server: IPC Server handler 8 on 60020, call batchUpdate([B@17b4239f, row => 02c241b4-9d32-452d-8dab-247f4af693eb, {column => content:title, value => '...', column => content:content, va
org.apache.hadoop.hbase.NotServingRegionException: items,01beddd6-813b-4f2b-ac48-a0cef395cb7e,1217543451296
at org.apache.hadoop.hbase.regionserver.HRegionServer.getRegion(HRegionServer.java:1436)
at org.apache.hadoop.hbase.regionserver.HRegionServer.batchUpdate(HRegionServer.java:1147)
at sun.reflect.GeneratedMethodAccessor12.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:616)
at org.apache.hadoop.hbase.ipc.HbaseRPC$Server.call(HbaseRPC.java:473)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:896)
2008-07-31 15:39:09,547 INFO org.apache.hadoop.hbase.regionserver.HRegion: Blocking updates for 'IPC Server handler 8 on 60020' on region items,8001eb31-98bb-4087-bd8d-e4b42805addb,1217543451296: Memcache size 64.0m is >= than blocking
2008-07-31 15:39:44,079 INFO org.apache.hadoop.hbase.regionserver.HRegion: Blocking updates for 'IPC Server handler 9 on 60020' on region items,8001eb31-98bb-4087-bd8d-e4b42805addb,1217543451296: Memcache size 64.0m is >= than blocking
2008-07-31 15:40:19,574 INFO org.apache.hadoop.hbase.regionserver.HRegion: Blocking updates for 'IPC Server handler 1 on 60020' on region items,8001eb31-98bb-4087-bd8d-e4b42805addb,1217543451296: Memcache size 64.0m is >= than blocking
2008-07-31 15:49:09,130 INFO org.apache.hadoop.hbase.regionserver.LogRoller: Rolling hlog. Number of entries: 1
2008-07-31 15:49:09,144 DEBUG org.apache.hadoop.hbase.regionserver.HLog: Closing current log writer /hbase/log_72.34.249.212_1217535541159_60020/hlog.dat.1217543884691
2008-07-31 15:49:09,146 INFO org.apache.hadoop.hbase.regionserver.HLog: New log writer created at /hbase/log_72.34.249.212_1217535541159_60020/hlog.dat.1217544549145
2008-07-31 16:03:09,060 DEBUG org.apache.hadoop.hbase.regionserver.HRegion: Started memcache flush for region items,8001eb31-98bb-4087-bd8d-e4b42805addb,1217543451296. Current region memcache size 64.0m
2008-07-31 16:03:09,467 INFO org.apache.hadoop.hbase.regionserver.HRegion: Unblocking updates for region items,8001eb31-98bb-4087-bd8d-e4b42805addb,1217543451296 'IPC Server handler 5 on 60020'
2008-07-31 16:03:09,478 INFO org.apache.hadoop.ipc.Server: Process Thread Dump: Discarding call batchUpdate([B@4e727e0e, row => c08408b4-b68c-433c-ba3f-d46d3ba73288, {column => content:title, value => '...', column => content:content, v

As you can see there was a 14 minute delay between updates being blocked, and the unblocking occurring.

All the pending batchUpdates were thrown out (too old) and then importing proceeded normally.

The same behavior repeated itself later on a different regionserver, and again after a while it unfroze, kicked out pending updates, and continued.