Hi,

Sorry for the multiple e-mails, it seems gmail didn't send my whole
message last time! Anyway here it goes again...

Whilst loading data via a mapreduce job into HBase I have started getting
this error :-

org.apache.hadoop.hbase.client.RetriesExhaustedException: Trying to
contact region server Some server, retryOnlyOne=true, index=0,
islastrow=false, tries=9, numtries=10, i=0, listsize=19,
region=source_documents,ipubmed\x219915054,1274525958679 for region
source_documents,ipubmed\x219915054,1274525958679, row 'u1012913162',
but failed after 10 attempts.
Exceptions:
at 
org.apache.hadoop.hbase.client.HConnectionManager$TableServers$Batch.process(HConnectionManager.java:1166)
at 
org.apache.hadoop.hbase.client.HConnectionManager$TableServers.processBatchOfRows(HConnectionManager.java:1247)
at org.apache.hadoop.hbase.client.HTable.flushCommits(HTable.java:609)

In the master there are the following three regions :-

source_documents,ipubmed\x219859228,1274701893687       hadoop1
1825870642      ipubmed\x219859228      ipubmed\x219915054
source_documents,ipubmed\x219915054,1274525958679       hadoop4
193393334        ipubmed\x219915054      u102193588
source_documents,u102193588,1274486550122                    hadoop4
2141795358      u102193588                    u105043522

and on one of our 5 nodes I found a region which start with

ipubmed\x219915054 and ends with u102002564

and on another I found the other half of the split which starts with

u102002564 and ends with u102193588

So it seems that the middle region on the master was split apart but
that failed to reach the master.

We've had a few problems over the last few days with hdfs nodes
failing due to lack of memory which has now been fixed but could have
been a cause of this problem.

What ways can a split fail to be received by the master and how long
would it take for hbase to fix this? I've read it periodically will
scan the META table to find problems like this but didn't say how
often? It has been about 12h here and our cluster didn't appear to
have fixed this missing split, is there a way to force the master to
rescan the META table? Will it fix problems like this given time?

Thanks,

-- 
Dan Harvey | Datamining Engineer
www.mendeley.com/profiles/dan-harvey

Mendeley Limited | London, UK | www.mendeley.com
Registered in England and Wales | Company Number 6419015

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