Package oracle.kv.hadoop.hive.table

Class TableHiveRecordReader

java.lang.Object

oracle.kv.hadoop.hive.table.TableHiveRecordReader

All Implemented Interfaces:

Closeable, AutoCloseable, RecordReader<Text,Text>

public class TableHiveRecordReader
extends Object
implements RecordReader<Text,Text>

Concrete implementation of RecordReader; used to read PrimaryKey/Row pairs from an InputSplit.

Note that this RecordReader is based on version 1 of MapReduce (as required by the Hive infrastructure), but wraps and delegates to a YARN based (MapReduce version 2) RecordReader. This is done because the RecordReader provided by Oracle NoSQL Database to support Hadoop integration is YARN based, and this class wishes to exploit and reuse the functionality already provided by the YARN based RecordReader class. - Note on Logging - Two loggers are currently employed by this class:

• One logger based on Log4j version 1, accessed via the org.apache.commons.logging wrapper.
• One logger based on the Log4j2 API.

Two loggers are necessary because Hive2 employs the Log4j2 logging mechanism, whereas logging in Big Data SQL 4.0 is still based on Log4j version 1. As a result, when one executes a Hive query and wishes to log output from this class, the Log4j2-based logger specified by this class must be added to the Hive2 logging configuration file. On the other hand, to log output from this class when executing a Big Data SQL query, the Log4j v1 logger must be added to the Big Data SQL logging configuration file. In the future, when Big Data SQL changes its logging mechanims from Log4j v1 to Log4j2, this class should be changed to employ only the Log4j2-based logger.

Constructor Summary

Constructors

Constructor	Description
TableHiveRecordReader(JobConf jobConf, TableRecordReader v2RecordReader)

Method Summary

Modifier and Type	Method	Description
void	close()
Text	createKey()	Get the current key.
Text	createValue()	Get the current value.
long	getPos()
float	getProgress()
boolean	next(Text key, Text value)

Methods inherited from class java.lang.Object

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

Constructor Detail

TableHiveRecordReader

public TableHiveRecordReader(JobConf jobConf,
                             TableRecordReader v2RecordReader)

Method Detail

close

public void close()
           throws IOException

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface RecordReader<Text,Text>

Throws:

IOException

getPos

public long getPos()
            throws IOException

Specified by:

getPos in interface RecordReader<Text,Text>

Throws:

IOException

getProgress

public float getProgress()

Specified by:

getProgress in interface RecordReader<Text,Text>

next

public boolean next(Text key,
                    Text value)
             throws IOException

Specified by:

next in interface RecordReader<Text,Text>

Throws:

IOException

createKey

public Text createKey()

Get the current key.

Specified by:

createKey in interface RecordReader<Text,Text>

Returns:

the current key or null if there is no current key

createValue

public Text createValue()

Get the current value.

Specified by:

createValue in interface RecordReader<Text,Text>

Returns:

the object that was read