I thought about that too. but then I need to write an bytes inspector and stick that into hive inspector factory. we also need to create a new datatype , such as blob , in hive's supported data types. Adding a new supported data type to hive is a non-trivial task, as more code will need to be touched.

I am just wondering if it is possible to get what I want to do without such big change.


Jimmy.

--------------------------------------------------
From: "Ted Yu" <yuzhih...@gmail.com>
Sent: Tuesday, October 12, 2010 4:12 PM
To: <dev@hive.apache.org>
Subject: Re: blob handling in hive

How about creating org.apache.hadoop.hive.serde2.io.BytesWritable which
wraps byte[] ?

On Tue, Oct 12, 2010 at 3:49 PM, Jinsong Hu <jinsong...@hotmail.com> wrote:

storing the blob in hbase is too costly. hbase compaction costs lots of
cpu. All I want to do is to be able to read the byte array out of a sequence
file, and map that byte array to an hive column.
I can write a SerDe for this purpose.

I tried to define the data to be array<tinyint>. I then tried to write
custom SerDe, after I get the byte array out of the disk, I need to map
it,

 so I wrote the code:
columnTypes
=TypeInfoUtils.getTypeInfosFromTypeString("int,string,array<tinyint>");

but then how to I convert the data in the row.set() method ?

I tried this:

      byte [] bContent=ev.get_content()==null ? null :
(ev.get_content().getData()==null ? null : ev.get_content().getData());
      org.apache.hadoop.hive.serde2.io.ByteWritable tContent =
bContent==null ? new org.apache.hadoop.hive.serde2.io.ByteWritable() : new
org.apache.hadoop.hive.serde2.io.ByteWritable(bContent[0]) ;
       row.set(2, tContent);

this works for a single byte, but doesn't work for byte array.
Any way that I can get the byte array returned in sql is appreciated.

Jimmy

--------------------------------------------------
From: "Ted Yu" <yuzhih...@gmail.com>
Sent: Tuesday, October 12, 2010 2:19 PM
To: <dev@hive.apache.org>
Subject: Re: blob handling in hive


 One way is to store blob in HBase and use HBaseHandler to access your
blob.

On Tue, Oct 12, 2010 at 2:14 PM, Jinsong Hu <jinsong...@hotmail.com>
wrote:

 Hi,
I am using sqoop to export data from mysql to hive. I noticed that hive don't have blob data type yet. is there anyway I can do so hive can store
blob ?

Jimmy




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