[hbase] Could not complete hdfs write out to flush file forcing regionserver 
restart
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                 Key: HADOOP-2311
                 URL: https://issues.apache.org/jira/browse/HADOOP-2311
             Project: Hadoop
          Issue Type: Bug
          Components: contrib/hbase
            Reporter: stack
            Priority: Minor


I've spent some time looking into this issue but there are not enough clues in 
the logs to tell where the problem is. Here's what I know.

Two region servers went down last night, a minute apart, during Paul Saab's 6hr 
run inserting 300million rows into hbase. The regionservers went down to force 
rerun of hlog and avoid possible data loss after a failure writing memory 
flushes to hdfs.

Here is the lead up to the failed flush:

...
2007-11-28 22:40:02,231 INFO  hbase.HRegionServer - MSG_REGION_OPEN : 
regionname: postlog,img149/4699/133lm0.jpg,1196318393738, startKey: 
<img149/4699/133lm0.jpg>, tableDesc: {name: postlog, families: {cookie:={name: 
cookie, max versions: 1, compression: NONE, in memory: false, max length: 
2147483647, bloom filter: none}, ip:={name: ip, max versions: 1, compression: 
NONE, in memory: false, max length: 2147483647, bloom filter: none}}}
2007-11-28 22:40:02,242 DEBUG hbase.HStore - starting 1703405830/cookie (no 
reconstruction log)
2007-11-28 22:40:02,741 DEBUG hbase.HStore - maximum sequence id for hstore 
1703405830/cookie is 29077708
2007-11-28 22:40:03,094 DEBUG hbase.HStore - starting 1703405830/ip (no 
reconstruction log)
2007-11-28 22:40:03,852 DEBUG hbase.HStore - maximum sequence id for hstore 
1703405830/ip is 29077708
2007-11-28 22:40:04,138 DEBUG hbase.HRegion - Next sequence id for region 
postlog,img149/4699/133lm0.jpg,1196318393738 is 29077709
2007-11-28 22:40:04,141 INFO  hbase.HRegion - region 
postlog,img149/4699/133lm0.jpg,1196318393738 available
2007-11-28 22:40:04,141 DEBUG hbase.HLog - changing sequence number from 
21357623 to 29077709
2007-11-28 22:40:04,141 INFO  hbase.HRegionServer - MSG_REGION_OPEN : 
regionname: postlog,img149/7512/dscn4444lightenedfi3.jpg,1196318393739, 
startKey: <img149/7512/dscn4444lightenedfi3.jpg>, tableDesc: {name: postlog, 
families: {cookie:={name: cookie, max versions: 1, compression: NONE, in 
memory: false, max length: 2147483647, bloom filter: none}, ip:={name: ip, max 
versions: 1, compression: NONE, in memory: false, max length: 2147483647, bloom 
filter: none}}}
2007-11-28 22:40:04,145 DEBUG hbase.HStore - starting 376748222/cookie (no 
reconstruction log)
2007-11-28 22:40:04,223 DEBUG hbase.HStore - maximum sequence id for hstore 
376748222/cookie is 29077708
2007-11-28 22:40:04,277 DEBUG hbase.HStore - starting 376748222/ip (no 
reconstruction log)
2007-11-28 22:40:04,353 DEBUG hbase.HStore - maximum sequence id for hstore 
376748222/ip is 29077708
2007-11-28 22:40:04,699 DEBUG hbase.HRegion - Next sequence id for region 
postlog,img149/7512/dscn4444lightenedfi3.jpg,1196318393739 is 29077709
2007-11-28 22:40:04,701 INFO  hbase.HRegion - region 
postlog,img149/7512/dscn4444lightenedfi3.jpg,1196318393739 available
2007-11-28 22:40:34,427 DEBUG hbase.HRegionServer - flushing region 
postlog,img143/1310/yashrk3.jpg,1196317258704
2007-11-28 22:40:34,428 DEBUG hbase.HRegion - Not flushing cache for region 
postlog,img143/1310/yashrk3.jpg,1196317258704: snapshotMemcaches() determined 
that there was nothing to do
2007-11-28 22:40:55,745 DEBUG hbase.HRegionServer - flushing region 
postlog,img142/8773/1001417zc4.jpg,1196317258703
2007-11-28 22:40:55,745 DEBUG hbase.HRegion - Not flushing cache for region 
postlog,img142/8773/1001417zc4.jpg,1196317258703: snapshotMemcaches() 
determined that there was nothing to do
2007-11-28 22:41:04,144 DEBUG hbase.HRegionServer - flushing region 
postlog,img149/4699/133lm0.jpg,1196318393738
2007-11-28 22:41:04,144 DEBUG hbase.HRegion - Started memcache flush for region 
postlog,img149/4699/133lm0.jpg,1196318393738. Size 74.7k
2007-11-28 22:41:04,764 DEBUG hbase.HStore - Added 
1703405830/ip/610047924323344967 with sequence id 29081563 and size 53.8k
2007-11-28 22:41:04,902 DEBUG hbase.HStore - Added 
1703405830/cookie/3147798053949544972 with sequence id 29081563 and size 41.3k
2007-11-28 22:41:04,902 DEBUG hbase.HRegion - Finished memcache flush for 
region postlog,img149/4699/133lm0.jpg,1196318393738 in 758ms, 
sequenceid=29081563
2007-11-28 22:41:04,902 DEBUG hbase.HStore - compaction for HStore 
postlog,img149/4699/133lm0.jpg,1196318393738/ip needed.
2007-11-28 22:41:04,903 DEBUG hbase.HRegion - 1703405830/ip needs compaction
2007-11-28 22:41:04,903 INFO  hbase.HRegion - starting compaction on region 
postlog,img149/4699/133lm0.jpg,1196318393738
2007-11-28 22:41:04,903 DEBUG hbase.HStore - started compaction of 4 files in 
/hbase/compaction.dir/hregion_1703405830/ip
2007-11-28 22:41:04,905 DEBUG hbase.HRegionServer - flushing region 
postlog,img149/7512/dscn4444lightenedfi3.jpg,1196318393739
2007-11-28 22:41:04,906 DEBUG hbase.HRegion - Started memcache flush for region 
postlog,img149/7512/dscn4444lightenedfi3.jpg,1196318393739. Size 133.1k
2007-11-28 22:41:05,087 DEBUG hbase.HStore - Added 
376748222/ip/8686640221458382286 with sequence id 29081604 and size 95.8k
2007-11-28 22:41:05,419 FATAL hbase.HRegionServer - Replay of hlog required. 
Forcing server restart
org.apache.hadoop.hbase.DroppedSnapshotException: java.io.IOException: Could 
not complete write to file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data by 
DFSClient_-1010714652
        at org.apache.hadoop.dfs.NameNode.complete(NameNode.java:323)
        at sun.reflect.GeneratedMethodAccessor13.invoke(Unknown Source)
        at 
sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:379)
        at org.apache.hadoop.ipc.Server$Handler.run(Server.java:596)

        at org.apache.hadoop.hbase.HRegion.internalFlushcache(HRegion.java:920)
        at org.apache.hadoop.hbase.HRegion.flushcache(HRegion.java:807)
        at 
org.apache.hadoop.hbase.HRegionServer$Flusher.run(HRegionServer.java:451)
...

Over in the namenode, I see the following related to the deleted file:

2007-11-28 22:40:48,546 DEBUG dfs.StateChange - *DIR* NameNode.mkdirs: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411
2007-11-28 22:40:48,546 DEBUG dfs.StateChange - DIR* NameSystem.mkdirs: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411
2007-11-28 22:40:48,546 DEBUG dfs.StateChange - DIR* FSDirectory.mkdirs: 
created directory /hbase/hregion_376748222/cookie/mapfiles/3557442410867103411
2007-11-28 22:40:48,552 DEBUG dfs.StateChange - *DIR* NameNode.create: file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data for 
DFSClient_-1010714652 at XX.XX.XX.29
2007-11-28 22:40:48,552 DEBUG dfs.StateChange - DIR* NameSystem.startFile: file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data for 
DFSClient_-1010714652 at XX.XX.XX.29
2007-11-28 22:40:48,552 DEBUG dfs.StateChange - DIR* FSDirectory.addFile: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data is added to 
the file system
2007-11-28 22:40:48,552 DEBUG dfs.StateChange - DIR* NameSystem.startFile: add 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data to namespace 
for DFSClient_-1010714652
2007-11-28 22:40:48,557 DEBUG dfs.StateChange - *DIR* NameNode.create: file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/index for 
DFSClient_-1010714652 at XX.XX.XX.29
2007-11-28 22:40:48,557 DEBUG dfs.StateChange - DIR* NameSystem.startFile: file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/index for 
DFSClient_-1010714652 XX.XX.XX.29
2007-11-28 22:40:48,558 DEBUG dfs.StateChange - DIR* FSDirectory.addFile: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/index is added to 
the file system
2007-11-28 22:40:48,558 DEBUG dfs.StateChange - DIR* NameSystem.startFile: add 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/index to namespace 
for DFSClient_-1010714652
2007-11-28 22:40:48,573 DEBUG dfs.StateChange - *BLOCK* NameNode.addBlock: file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data for 
DFSClient_-1010714652
2007-11-28 22:40:48,573 DEBUG dfs.StateChange - BLOCK* 
NameSystem.getAdditionalBlock: file 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data for 
DFSClient_-1010714652
2007-11-28 22:40:48,573 DEBUG dfs.StateChange - DIR* FSDirectory.addFile: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data with 
blk_-6398846109350112398 block is added to the in-memory file system
2007-11-28 22:40:48,573 INFO  dfs.StateChange - BLOCK* 
NameSystem.allocateBlock: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data. 
blk_-6398846109350112398
.....
2007-11-28 22:40:48,717 DEBUG dfs.StateChange - *DIR* NameNode.delete: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411
2007-11-28 22:40:48,717 DEBUG dfs.StateChange - DIR* NameSystem.delete: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411
2007-11-28 22:40:48,717 DEBUG dfs.StateChange - DIR* FSDirectory.delete: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411
2007-11-28 22:40:48,717 DEBUG dfs.StateChange - DIR* 
FSDirectory.unprotectedDelete: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411 is removed
....
2007-11-28 22:40:48,826 DEBUG dfs.StateChange - *DIR* NameNode.complete: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data for 
DFSClient_-1010714652
2007-11-28 22:40:48,826 DEBUG dfs.StateChange - DIR* NameSystem.completeFile: 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data for 
DFSClient_-1010714652
2007-11-28 22:40:48,827 WARN  dfs.StateChange - DIR* NameSystem.completeFile: 
failed to complete 
/hbase/hregion_376748222/cookie/mapfiles/3557442410867103411/data because 
dir.getFileBlocks() is null  and pendingFile is null

Only delete I see is on compaction completion but reading code doesn't look 
like its possible for deletes to be confused.

Will add extra logging to see if I can figure how the delete is coming about.

(We've fixed a similar problem before when compactions were done at region 
level)

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