com.facebook.presto.orc.reader

Class MapFlatBatchStreamReader

java.lang.Object

com.facebook.presto.orc.reader.MapFlatBatchStreamReader

All Implemented Interfaces:

BatchStreamReader, StreamReader

public class MapFlatBatchStreamReader
extends Object
implements BatchStreamReader

Flat Maps are a layout of maps supported in DWRF.

Values associated with different keys are stored in separate streams rather than having a single set of value streams for the map.

There is a ColumnEncoding associated with the value streams for a given key. All the ColumnEncodings for values have the same columnId, and use a sequenceId to distinguish them. The ColumnEncoding also contains the key it is associated with as metadata.

Note that the ColumnEncoding with sequenceId 0 for the values has no data associated with it, only statistics. Similarly there is a ColumnEncoding for the key stream which has no data associated with it, only statistics, so it is not used in this class.

Constructor Summary

Constructors

Constructor and Description
MapFlatBatchStreamReader(Type type, StreamDescriptor streamDescriptor, org.joda.time.DateTimeZone hiveStorageTimeZone, OrcRecordReaderOptions options, OrcAggregatedMemoryContext systemMemoryContext)

Method Summary

Modifier and Type	Method and Description
void	close()
long	getRetainedSizeInBytes()
void	prepareNextRead(int batchSize)
Block	readBlock()
void	startRowGroup(InputStreamSources dataStreamSources)
void	startStripe(Stripe stripe)
String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

MapFlatBatchStreamReader

public MapFlatBatchStreamReader(Type type,
                                StreamDescriptor streamDescriptor,
                                org.joda.time.DateTimeZone hiveStorageTimeZone,
                                OrcRecordReaderOptions options,
                                OrcAggregatedMemoryContext systemMemoryContext)
                         throws OrcCorruptionException

Throws:

OrcCorruptionException

Method Detail

prepareNextRead

public void prepareNextRead(int batchSize)

Specified by:

prepareNextRead in interface BatchStreamReader

readBlock

public Block readBlock()
                throws IOException

Specified by:

readBlock in interface BatchStreamReader

Throws:

IOException

startStripe

public void startStripe(Stripe stripe)
                 throws IOException

Specified by:

startStripe in interface StreamReader

Throws:

IOException

startRowGroup

public void startRowGroup(InputStreamSources dataStreamSources)
                   throws IOException

Specified by:

startRowGroup in interface StreamReader

Throws:

IOException

toString

public String toString()

Overrides:

toString in class Object

close

public void close()

Specified by:

close in interface StreamReader

getRetainedSizeInBytes

public long getRetainedSizeInBytes()

Specified by:

getRetainedSizeInBytes in interface StreamReader