Yes, what Erik said. MapFile is a binary format. What you are some
preamble up front listing the key and value class types plus some
miscellaneous meta data. Then, per key and value, these are serialized
Writable types.
Move to hbase 0.20.0. It uses hfile instead of mapfile. There is a nice
little utility that does a toString on the hfile binary serializations that
prints prettier than the below.
St.Ack
On Tue, Sep 22, 2009 at 3:10 AM, stchu <stchu.cl...@gmail.com> wrote:
> Hi,
>
> I use Hadoop 0.19.1 and HBase 0.19.3.
> I write a simple table which have 2 column families (Level0:trail_id,
> Level1:trail_id).
> And I put the data (4 rows) into hbase table:
> 120_25 column=Level0:trail_id,
> timestamp=2009091613240001, value=39999;21234
> 121.1_23.4 column=Level1:trail_id,
> timestamp=2009091613240001, value=50001;00048;111110
> 121.1_25.0 column=Level1:trail_id,
> timestamp=2009091613240001, value=39999;21234
> 121_25 column=Level0:trail_id,
> timestamp=2009091613240003, value=39999;21234;000001;000003
>
>
> I find the content of files in HDFS is:
>
> for the mapfile Level0:
> SEQ
> !org.apache.hadoop.hbase.HStoreKey1org.apache.hadoop.hbase.io.ImmutableBytesWritable�������h
> =
> �p{9
> ��1������.��� 120_25 Level0:trail_id� #B ����� 39999;21234���<��� 121_25
> Level0:trail_id� #B ����� 39999;21234;000001;000003
>
> for the mapfile Level1:
> SEQ
> !org.apache.hadoop.hbase.HStoreKey1org.apache.hadoop.hbase.io.ImmutableBytesWritable�������>T�
> �4�q-�� ��.���9���#
> 121.1_23.4 Level1:trail_id� #B ����� 50001;00048;111110���2���#
> 121.1_25.0 Level1:trail_id� #B ����� 39999;21234
>
>
> I wonder that what the messy code means? Is that "offset" and/or
> "timestamps"?
> Besides, since hbase store the mapfile depends on columnfamily, why we need
> to save that (in this case: Level0 and Level1)?
>
> I appreciate your helps or guides.
>
> stchu
>
