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From Keys Botzum <kbot...@maprtech.com>
Subject Re: Accumulo on MapR Continued
Date Sat, 31 Mar 2012 02:12:00 GMT
Billie,

Thanks for the quick reply.  I did some checking and the Hadoop docs indicate that seeking
past the end of the file is illegal. 

http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/fs/FSDataInputStream.html#seek%28long%29
 seek

public void seek(long desired)
          throws IOException
Description copied from interface: Seekable
Seek to the given offset from the start of the file. The next read() will be from that location.
Can't seek past the end of the file.

Specified by:
seek in interface Seekable
Throws:
IOException

The code below that is seeking to the file length is actually seeking one byte past the end
of the file since the first byte in a file is byte zero. To me this seems like an Accumulo
bug. Can this be fixed?

Thanks,
Keys
________________________________
Keys Botzum
Senior Principal Technologist
WW Systems Engineering
kbotzum@maprtech.com
443-718-0098
MapR Technologies
http://www.mapr.com



On Mar 30, 2012, at 5:04 PM, Billie J Rinaldi wrote:

> I ran the following JUnit test and verified that the value printed out was the file length.
> 
>  @Test
>  public void testSeekToEOF() throws IOException {
>    FileSystem fs = FileSystem.get(new Configuration());
>    FSDataInputStream fdi = fs.open(new Path("README"));
>    System.out.println("seeking to end: " + fdi.available());
>    fdi.seek(fdi.available());
>    fdi.close();
>  }
> 
> 
> ----- Original Message -----
>> From: "Keys Botzum" <kbotzum@maprtech.com>
>> To: user@accumulo.apache.org
>> Sent: Friday, March 30, 2012 4:56:09 PM
>> Subject: Re: Accumulo on MapR Continued
>> Can you share the program? I can try running it and answer your
>> question. I can also of course check with MapR engineering to see if
>> that's the issue.
>> 
>> 
>> Much appreciated,
>> Keys
>> 
>> ________________________________
>> Keys Botzum
>> Senior Principal Technologist
>> WW Systems Engineering
>> kbotzum@maprtech.com
>> 443-718-0098
>> MapR Technologies
>> http://www.mapr.com
>> 
>> 
>> 
>> 
>> 
>> On Mar 30, 2012, at 4:48 PM, Billie J Rinaldi wrote:
>> 
>> 
>> 
>> On Friday, March 30, 2012 2:07:49 PM, "Keys Botzum" <
>> kbotzum@maprtech.com > wrote:
>> 
>> 
>> 30 11:00:15,778 [tabletserver.Tablet] ERROR: Failed to find lastkey
>> 
>> 
>> Seeking beyond EOF, filelen 733, wantpos 733
>> 
>> It looks like Accumulo is trying to seek to the last position in a
>> file. I just wrote a little program that opens a file in HDFS and
>> seeks to its file length, and it didn't throw an error. Does MapR not
>> allow this? If that is the desired MapR behavior, we could try to
>> determine whether Accumulo could avoid performing that seek.
>> 
>> Billie


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