Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
HBase, mail # dev - HLogSplit error with hadoop-2.0.3-alpha and hbase trunk


Copy link to this message
-
Re: HLogSplit error with hadoop-2.0.3-alpha and hbase trunk
Anoop John 2013-05-08, 19:00
>However this doesn't explain why sequencefile has no such problems

What I can see is we use FSDataInputStream in case of SequenecFileLogReader
(Not FSInputStream) and we use FSDataInputStream #readInt() (WALEdit#read...).
This inturn reads the int from stream by calling in.read() 4 times making
sure we read full int (If it is not EOF issue)

May be we can try out this way and test tomorow Ram.

BTW IOUtils.readFully() is not returning the actual # bytes read it looks.

-Anoop-

On Thu, May 9, 2013 at 12:07 AM, Sergey Shelukhin <[EMAIL PROTECTED]>wrote:

> 589824 is divisible by 4096, default buffer size. Que groundless
> suspicions. However this doesn't explain why sequencefile has no such
> problems. Do you have any more numbers with this?
> I am in meetings now, let me try readFully after I come back from lunch
>
> On Wed, May 8, 2013 at 11:23 AM, ramkrishna vasudevan <
>  [EMAIL PROTECTED]> wrote:
>
> > >The length is from read call. This looks pretty suspicious, if the
> stream
> > is not EOF why would it return less bytes?
> >
> > Infact this happened for an entry in the middle of the HLog.  Write some
> > data using LoadTestTool.  Try to use the HLog tool to read the HLog file
> > you will end up in this issue. (most of the times).
> >
> > Regards
> > Ram
> >
> >
> >
> > On Wed, May 8, 2013 at 11:48 PM, Sergey Shelukhin <
> [EMAIL PROTECTED]
> > >wrote:
> >
> > > if (length != intBytes.length) throw new IOException("Failed read of
> int
> > > length " + length);
> > > The length is from read call. This looks pretty suspicious, if the
> stream
> > > is not EOF why would it return less bytes? I will try to repro today.
> > >
> > > On Wed, May 8, 2013 at 5:46 AM, ramkrishna vasudevan <
> > > [EMAIL PROTECTED]> wrote:
> > >
> > > > On further debugging found that this issue happens with
> ProtoBufWriter
> > > and
> > > > not with sequenceFileWriter.(atleast we could not reproduce it with
> > > > different runs)
> > > >
> > > > We can see that the HLog has more data in it but while reading one of
> > the
> > > > lines in the HLog this error happens.  So pretty much sure that it is
> > not
> > > > EOF.
> > > > Verified DFS logs but could not find any exceptions out there too.
> > > >
> > > > We will try to figure out more on this tomorrow.
> > > >
> > > > Regards
> > > > Ram
> > > >
> > > >
> > > > On Wed, May 8, 2013 at 11:34 AM, ramkrishna vasudevan <
> > > > [EMAIL PROTECTED]> wrote:
> > > >
> > > > > Ok so i tried this out with hadoop 2.0.4 and also with Sergey's
> > patch.
> > > > >  The issue is reproducible in all version of hadoop but not always.
> > > > > I am able to get the errors like this
> > > > >
> > > > > 2013-05-07 17:11:08,827 WARN  [SplitLogWorker-ram.sh.intel.com<http://splitlogworker-ram.sh.intel.com/>
> > > > ,60020,1367961009182]
> > > > > org.apache.hadoop.hbase.regionserver.SplitLogWorker: log splitting
> of
> > > > .logs/
> > > > > ram.sh.intel.com,60020,1367960957620-splitting/ram.sh.intel.com
> > > > %2C60020%2C1367960957620.1367960993389
> > > > > failed, returning error
> > > > > java.io.IOException: Error  while reading 1 WAL KVs; started
> reading
> > at
> > > > > 589822 and read up to 589824
> > > > > at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.wal.ProtobufLogReader.readNext(ProtobufLogReader.java:162)
> > > > >  at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.wal.ReaderBase.next(ReaderBase.java:88)
> > > > > at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.wal.ReaderBase.next(ReaderBase.java:75)
> > > > >  at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.getNextLogLine(HLogSplitter.java:775)
> > > > > at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.splitLogFile(HLogSplitter.java:459)
> > > > >  at
> > > > >
> > > >
> > >
> >
> org.apache.hadoop.hbase.regionserver.wal.HLogSplitter.splitLogFile(HLogSplitter.java:388)