job information not found in JobContext - hadoop

Question

I am running a Java program on a remote computer and trying to read the split data using RecordReader object but instead getting:
Exception in thread "main" java.io.IOException: job information not found in JobContext. HCatInputFormat.setInput() not called?
I already have called the following:
_hcatInputFmt = HCatInputFormat.setInput(_myJob, db,tbl);
and then creating the RecordReader object as:
_hcatInputFmt.createRecordReader(hSplit, taskContext)
On debugging it fails while searching for the value of the key: HCAT_KEY_JOB_INFO in job configuration object, while trying to create a RecordReader object.
How do I set this value? Any pointers will be helpful.
Thanks.

Answer 1

We have to use getConfiguration() method to get the configuration from the job object. The configuration object used in creating the job object won't do it.

Answer 2

I had the same problem, you shuold use:
HCatInputFormat.setInput(job, dbName, inputTableName);
HCatSchema inputschema = HCatBaseInputFormat.getTableSchema(job.getConfiguration());
not
HCatInputFormat.setInput(job, dbName, inputTableName);
HCatSchema inputschema = HCatBaseInputFormat.getTableSchema(getConf());
Because, when you use Job.getInstance(conf), it will copy the conf, you can't use the original conf. Here is the code:
/**
* A new configuration with the same settings cloned from another.
*
* #param other the configuration from which to clone settings.
*/
#SuppressWarnings("unchecked")
public Configuration(Configuration other) {
this.resources = (ArrayList<Resource>) other.resources.clone();
synchronized(other) {
if (other.properties != null) {
this.properties = (Properties)other.properties.clone();
}
if (other.overlay!=null) {
this.overlay = (Properties)other.overlay.clone();
}
this.updatingResource = new ConcurrentHashMap<String, String[]>(
other.updatingResource);
this.finalParameters = Collections.newSetFromMap(
new ConcurrentHashMap<String, Boolean>());
this.finalParameters.addAll(other.finalParameters);
}
synchronized(Configuration.class) {
REGISTRY.put(this, null);
}
this.classLoader = other.classLoader;
this.loadDefaults = other.loadDefaults;
setQuietMode(other.getQuietMode());
}