hbase-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Silvio Di gregorio <silvio.digrego...@gmail.com>
Subject Re: Job MapReduce to populate HBase Table
Date Mon, 13 Apr 2015 12:21:58 GMT
the signature of the write method is:
write(ImmutableBytesWritable
<eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/ws-cloudera%5C/JAR%5C/hadoop-mapreduce-client-core-2.0.0-cdh4.0.0.jar%3Corg.apache.hadoop.mapreduce(TaskInputOutputContext.class%E2%98%83TaskInputOutputContext~write~TKEYOUT;~TVALUEOUT;%E2%98%82org.apache.hadoop.hbase.io.ImmutableBytesWritable>
arg0, Writable
<eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/ws-cloudera%5C/JAR%5C/hadoop-mapreduce-client-core-2.0.0-cdh4.0.0.jar%3Corg.apache.hadoop.mapreduce(TaskInputOutputContext.class%E2%98%83TaskInputOutputContext~write~TKEYOUT;~TVALUEOUT;%E2%98%82org.apache.hadoop.io.Writable>
arg1)

arg0 don't accept NulWritable.get(), instead "null"

2015-04-13 14:13 GMT+02:00 Silvio Di gregorio <silvio.digregorio@gmail.com>:

> in documentation (http://hbase.apache.org/0.94/book/mapreduce.example.html),
> when the Reduce extends the TableReducer class the write method
> put the key null, or rather NullWritable like Shahab Say.
> However, the error has disappeared when i removed the
> "hbase-client-0.96.0-hadoop1.jar" and inserted  "hbase-0.94.6-cdh4.3.0.jar".
> Sorry but i don't understand, I knew only that the Context object had not
> accepted a PUT where was required WRITABLE with the
> "hbase-client-0.96.0-hadoop1.jar" jar in classpath. With the
> "hbase-0.94.6-cdh4.3.0.jar" it is possible.
>
> 2015-04-13 13:52 GMT+02:00 Jean-Marc Spaggiari <jean-marc@spaggiari.org>:
>
>> Oh, Shahab is write! That's what happend when you write emails before your
>> coffee ;) I confused with your "Put" key ;)  Looked to quickly...
>>
>> JM
>>
>> 2015-04-13 7:46 GMT-04:00 Shahab Yunus <shahab.yunus@gmail.com>:
>>
>> > For the null key you should use NullWritable class, as discussed here:
>> >
>> >
>> http://stackoverflow.com/questions/16198752/advantages-of-using-nullwritable-in-hadoop
>> >
>> > Regards,
>> > Shahab
>> >
>> > On Mon, Apr 13, 2015 at 7:01 AM, Jean-Marc Spaggiari <
>> > jean-marc@spaggiari.org> wrote:
>> >
>> > > Hi Silvio,
>> > >
>> > > What is the key you try to write into your HBase table? From your
>> code,
>> > > sound like you want your key to be null for all your values, which is
>> not
>> > > possible in HBase.
>> > >
>> > > JM
>> > >
>> > > 2015-04-13 6:37 GMT-04:00 Silvio Di gregorio <
>> > silvio.digregorio@gmail.com
>> > > >:
>> > >
>> > > > Hi,
>> > > > In Reduce phase when i write to Hbase Table "PFTableNa"
>> > > > context.write(null , put);
>> > > > Eclipse say me:
>> > > > *"The method write(ImmutableBytesWritable, Writable) in the type
>> > > >
>> > >
>> >
>> TaskInputOutputContext<Text,BytesWritable,ImmutableBytesWritable,Writable>
>> > > > is not applicable for the arguments (null, Put)"*
>> > > >
>> > > > *put *is org
>> > > >
>> > > >
>> > >
>> >
>> <eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/workspace-luna%5C/hbase-client-0.96.0-hadoop1.jar%3Corg>
>> > > > .apache
>> > > >
>> > > >
>> > >
>> >
>> <eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/workspace-luna%5C/hbase-client-0.96.0-hadoop1.jar%3Corg.apache>
>> > > > .hadoop
>> > > >
>> > > >
>> > >
>> >
>> <eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/workspace-luna%5C/hbase-client-0.96.0-hadoop1.jar%3Corg.apache.hadoop>
>> > > > .hbase
>> > > >
>> > > >
>> > >
>> >
>> <eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/workspace-luna%5C/hbase-client-0.96.0-hadoop1.jar%3Corg.apache.hadoop.hbase>
>> > > > .client
>> > > >
>> > > >
>> > >
>> >
>> <eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/workspace-luna%5C/hbase-client-0.96.0-hadoop1.jar%3Corg.apache.hadoop.hbase.client>
>> > > > .Put
>> > > >
>> > > >
>> > >
>> >
>> <eclipse-javadoc:%E2%98%82=LoadUnico/C:%5C/Users%5C/sdigregorio%5C/workspace-luna%5C/hbase-client-0.96.0-hadoop1.jar%3Corg.apache.hadoop.hbase.client(Put.class%E2%98%83Put>.Put(byte[]
>> > > > row)
>> > > > byte[] rowkey = key.getBytes();
>> > > > Put put = new Put(rowkey);
>> > > >
>> > > > the signature of the reduce method:
>> > > > reduce( Text key,Iterable<BytesWritable> values, Context context)
>> > > >
>> > > > and
>> > > >
>> > > > public static class Reduce extends TableReducer<Text, BytesWritable,
>> > > > ImmutableBytesWritable>{
>> > > >
>> > > > in the main method:
>> > > > Configuration conf = HBaseConfiguration.create();
>> > > > Job job = new Job(conf, "LetturaFileHDFS2HBase");
>> > > > ...
>> > > > TableMapReduceUtil.initTableReducerJob("PFTableNa", Reduce.class,
>> job);
>> > > >
>> > > > Thanks a lot
>> > > > Silvio
>> > > >
>> > >
>> >
>>
>
>

Mime
  • Unnamed multipart/alternative (inline, None, 0 bytes)
View raw message