org.apache.hadoop.hive.druid.serde

Class DruidQueryRecordReader<T extends io.druid.query.BaseQuery<R>,R extends Comparable<R>>

java.lang.Object

org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

org.apache.hadoop.hive.druid.serde.DruidQueryRecordReader<T,R>

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Direct Known Subclasses:

DruidGroupByQueryRecordReader, DruidSelectQueryRecordReader, DruidTimeseriesQueryRecordReader, DruidTopNQueryRecordReader

public abstract class DruidQueryRecordReader<T extends io.druid.query.BaseQuery<R>,R extends Comparable<R>>
extends org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>
implements org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Base record reader for given a Druid query. This class contains the logic to send the query to the broker and retrieve the results. The transformation to emit records needs to be done by the classes that extend the reader. The key for each record will be a NullWritable, while the value will be a DruidWritable containing the timestamp as well as all values resulting from the query.

Field Summary

Fields

Modifier and Type	Field and Description
protected T	query Query that Druid executes.
protected Iterator<R>	results Query results.

Constructor Summary

Constructors

Constructor and Description
DruidQueryRecordReader()

Method Summary

Modifier and Type	Method and Description
void	close()
org.apache.hadoop.io.NullWritable	createKey()
protected abstract T	createQuery(String content)
protected abstract List<R>	createResultsList(InputStream content)
DruidWritable	createValue()
abstract org.apache.hadoop.io.NullWritable	getCurrentKey()
abstract DruidWritable	getCurrentValue()
long	getPos()
abstract float	getProgress()
void	initialize(org.apache.hadoop.mapreduce.InputSplit split, org.apache.hadoop.conf.Configuration conf)
void	initialize(org.apache.hadoop.mapreduce.InputSplit split, org.apache.hadoop.mapreduce.TaskAttemptContext context)
abstract boolean	next(org.apache.hadoop.io.NullWritable key, DruidWritable value)
abstract boolean	nextKeyValue()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

query

protected T extends io.druid.query.BaseQuery<R> query

Query that Druid executes.

results

protected Iterator<R extends Comparable<R>> results

Query results.

Constructor Detail

DruidQueryRecordReader

public DruidQueryRecordReader()

Method Detail

initialize

public void initialize(org.apache.hadoop.mapreduce.InputSplit split,
                       org.apache.hadoop.mapreduce.TaskAttemptContext context)
                throws IOException

Specified by:

initialize in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Throws:

IOException

initialize

public void initialize(org.apache.hadoop.mapreduce.InputSplit split,
                       org.apache.hadoop.conf.Configuration conf)
                throws IOException

Throws:

IOException

createQuery

protected abstract T createQuery(String content)
                          throws IOException

Throws:

IOException

createResultsList

protected abstract List<R> createResultsList(InputStream content)
                                      throws IOException

Throws:

IOException

createKey

public org.apache.hadoop.io.NullWritable createKey()

Specified by:

createKey in interface org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

createValue

public DruidWritable createValue()

Specified by:

createValue in interface org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

next

public abstract boolean next(org.apache.hadoop.io.NullWritable key,
                             DruidWritable value)
                      throws IOException

Specified by:

next in interface org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Throws:

IOException

getPos

public long getPos()

Specified by:

getPos in interface org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

nextKeyValue

public abstract boolean nextKeyValue()
                              throws IOException

Specified by:

nextKeyValue in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Throws:

IOException

getCurrentKey

public abstract org.apache.hadoop.io.NullWritable getCurrentKey()
                                                         throws IOException,
                                                                InterruptedException

Specified by:

getCurrentKey in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Throws:

IOException

InterruptedException

getCurrentValue

public abstract DruidWritable getCurrentValue()
                                       throws IOException,
                                              InterruptedException

Specified by:

getCurrentValue in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Throws:

IOException

InterruptedException

getProgress

public abstract float getProgress()
                           throws IOException

Specified by:

getProgress in interface org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Specified by:

getProgress in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Throws:

IOException

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface org.apache.hadoop.mapred.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>

Specified by:

close in class org.apache.hadoop.mapreduce.RecordReader<org.apache.hadoop.io.NullWritable,DruidWritable>