Getting Hbase Exception No regions passed - hadoop

Question

Hi i am new to Hbase and im trying to learn how to load bulk data to Hbase table using MapReduce
But i am getting below Exception
Exception in thread "main" java.lang.IllegalArgumentException: No regions passed
at org.apache.hadoop.hbase.mapreduce.HFileOutputFormat2.writePartitions(HFileOutputFormat2.java:307)
at org.apache.hadoop.hbase.mapreduce.HFileOutputFormat2.configurePartitioner(HFileOutputFormat2.java:527)
at org.apache.hadoop.hbase.mapreduce.HFileOutputFormat2.configureIncrementalLoad(HFileOutputFormat2.java:391)
at org.apache.hadoop.hbase.mapreduce.HFileOutputFormat2.configureIncrementalLoad(HFileOutputFormat2.java:356)
at JobDriver.run(JobDriver.java:108)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:70)
at org.apache.hadoop.util.ToolRunner.run(ToolRunner.java:84)
at JobDriver.main(JobDriver.java:34)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.apache.hadoop.util.RunJar.main(RunJar.java:212)
This is mY Mapper Code
public void map(LongWritable key, Text value, Context context) throws IOException, InterruptedException {
System.out.println("Value in Mapper"+value.toString());
String[] values = value.toString().split(",");
byte[] row = Bytes.toBytes(values[0]);
ImmutableBytesWritable k = new ImmutableBytesWritable(row);
KeyValue kvProtocol = new KeyValue(row, "PROTOCOLID".getBytes(), "PROTOCOLID".getBytes(), values[1]
.getBytes());
context.write(k, kvProtocol);
}
This is my Job Configuration
public class JobDriver extends Configured implements Tool{
public static void main(String[] args) throws Exception {
// TODO Auto-generated method stub
ToolRunner.run(new JobDriver(), args);
System.exit(0);
}
#Override
public int run(String[] arg0) throws Exception {
// TODO Auto-generated method stub
// HBase Configuration
System.out.println("**********Starting Hbase*************");
Configuration conf = HBaseConfiguration.create();
Job job = new Job(conf, "TestHFileToHBase");
job.setJarByClass(JobDriver.class);
job.setOutputKeyClass(ImmutableBytesWritable.class);
job.setOutputValueClass(KeyValue.class);
job.setMapperClass(LoadMapper.class);
job.setOutputFormatClass(HFileOutputFormat2.class);
HTable table = new HTable(conf, "kiran");
FileInputFormat.addInputPath(job, new Path("hdfs://192.168.61.62:9001/sampledata.csv"));
FileOutputFormat.setOutputPath(job, new Path("hdfs://192.168.61.62:9001/deletions_6.csv"));
HFileOutputFormat2.configureIncrementalLoad(job, table);
//System.exit(job.waitForCompletion(true) ? 0 : 1);
return job.waitForCompletion(true) ? 0 : 1;
}
}
Can Anyone please help me in resolvin the exception.

Answer 1

You have to create the table first. You can do it with the below code
//Create table and do pre-split
HTableDescriptor descriptor = new HTableDescriptor(
Bytes.toBytes(tableName)
);
descriptor.addFamily(
new HColumnDescriptor(Constants.COLUMN_FAMILY_NAME)
);
HBaseAdmin admin = new HBaseAdmin(config);
byte[] startKey = new byte[16];
Arrays.fill(startKey, (byte) 0);
byte[] endKey = new byte[16];
Arrays.fill(endKey, (byte)255);
admin.createTable(descriptor, startKey, endKey, REGIONS_COUNT);
admin.close();
or directly from the hbase shell with the command:
create 'kiran', 'colfam1'
The exception is caused because the startkeys list is empty: line 306
More info can be found here.
Note that the table name must be the same with the one you use in your code (kiran).