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From Jean-Daniel Cryans <jdcry...@apache.org>
Subject Re: HBase 0.90.4 missing data in production
Date Thu, 03 Nov 2011 17:34:13 GMT
Important questions that Stack asked that remain unanswered:

> On restart, are we splitting wal logs or is it a 'clean' restart where no
> wals are split?

> Can you figure what the missing data is?  Is it all from same one or
> two regions?

Basically if there is indeed missing data, we need to figure where
it's coming from. Something helpful could also be a bigger log
snippet, the stack traces you pasted does show something that "looks"
bad but IIRC that NPE comes out only when the file was already closed
by something else so it could have happened while the region server
was shutting... or not, I can't tell without the context.



On Wed, Nov 2, 2011 at 10:15 PM, Vladimir Rodionov
<vrodionov@carrieriq.com> wrote:
> 1. The Tool opens cursor to the database (RDBMS) and reads 'rowid's . We keep ROWIDs
> 2. Then using first N (configurable) rowids it fetches these rows from HBase using HBase
bulk get API.
> HBase restart :
> stop-hbase
> start-hbase
> on Master node
> I do not kill RS - its dangerous :)
> Best regards,
> Vladimir Rodionov
> Principal Platform Engineer
> Carrier IQ, www.carrieriq.com
> e-mail: vrodionov@carrieriq.com
> ________________________________________
> From: saint.ack@gmail.com [saint.ack@gmail.com] On Behalf Of Stack [stack@duboce.net]
> Sent: Wednesday, November 02, 2011 2:56 PM
> To: dev@hbase.apache.org
> Subject: Re: HBase 0.90.4 missing data in production
> On Wed, Nov 2, 2011 at 1:24 PM, Vladimir Rodionov
> <vrodionov@carrieriq.com> wrote:
>> We can confirm that by running  our own internal tool.
> Whats this tool doing Vladimir?  Is it running against HBase API?
>> It seems, that we loose only during first restart
> How are you doing the restart?  You killing regionservers?  On
> restart, are we splitting wal logs or is it a 'clean' restart where no
> wals are split?
> Can you figure what the missing data is?  Is it all from same one or
> two regions?
>> Table's TTL = 1 year. There is a slim chance that we load data with timestamps more
than one year behind, but it does not explain the difference
>> between total number of rows before and after cluster's restart.
> I'd think that if your 'internal tool' found the stuff before the
> restart, then this is probably ok (a year could have elapsed over the
> restart I suppose but that be odd...)
>> All RS are time synched.
>> In Master log I do not see any WARN or ERRORs during cluster re-start. In RS logs
I see a lot of:
>> 2011-11-02 00:16:07,620 INFO org.apache.hadoop.hbase.regionserver.wal.HLog: Roll
entries=76, filesize=68053806. New hlog /hbase/.logs/us01-ciqps1-grid01.carrieriq.com,60020,1320187507171/us01-ciqps1-grid01.carrieriq.com%3A60020.1320192967380
>> 2011-11-02 00:16:07,621 INFO org.apache.hadoop.io.compress.CodecPool: Got brand-new
>> 2011-11-02 00:16:07,621 FATAL org.apache.hadoop.hbase.regionserver.wal.HLog: Could
not append. Requesting close of hlog
>> java.io.IOException: Reflection
>>        at org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogWriter.sync(SequenceFileLogWriter.java:147)
>>        at org.apache.hadoop.hbase.regionserver.wal.HLog.sync(HLog.java:1002)
>>        at org.apache.hadoop.hbase.regionserver.wal.HLog.append(HLog.java:955)
>>        at org.apache.hadoop.hbase.regionserver.HRegion.doMiniBatchPut(HRegion.java:1483)
>>        at org.apache.hadoop.hbase.regionserver.HRegion.put(HRegion.java:1392)
>>        at org.apache.hadoop.hbase.regionserver.HRegionServer.multi(HRegionServer.java:2591)
>>        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.hbase.ipc.HBaseRPC$Server.call(HBaseRPC.java:570)
>>        at org.apache.hadoop.hbase.ipc.HBaseServer$Handler.run(HBaseServer.java:1039)
>> Caused by: java.lang.reflect.InvocationTargetException
>>        at sun.reflect.GeneratedMethodAccessor2.invoke(Unknown Source)
>>        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
>>        at java.lang.reflect.Method.invoke(Method.java:597)
>>        at org.apache.hadoop.hbase.regionserver.wal.SequenceFileLogWriter.sync(SequenceFileLogWriter.java:145)
>>        ... 10 more
>> Caused by: java.lang.NullPointerException
>>        at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.closeThreads(DFSClient.java:3306)
>>        at org.apache.hadoop.hdfs.DFSClient$DFSOutputStream.sync(DFSClient.java:3216)
>>        at org.apache.hadoop.fs.FSDataOutputStream.sync(FSDataOutputStream.java:97)
>>        at org.apache.hadoop.io.SequenceFile$Writer.syncFs(SequenceFile.java:944)
>>        ... 14 more
> Perhaps a newer CDH would have fix for this?
>> This is probably not all ERRORS and FATALs I am continuing investigation and will
post my other findings later.
> Let us know.
> St.Ack
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