org.apache.lucene.codecs.memory

Class DirectDocValuesFormat

java.lang.Object

org.apache.lucene.codecs.DocValuesFormat

org.apache.lucene.codecs.memory.DirectDocValuesFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

public class DirectDocValuesFormat
extends DocValuesFormat

In-memory docvalues format that does no (or very little) compression. Indexed values are stored on disk, but then at search time all values are loaded into memory as simple java arrays. For numeric values, it uses byte[], short[], int[], long[] as necessary to fit the range of the values. For binary values, there is an int (4 bytes) overhead per value.

Limitations:

• For binary and sorted fields the total space required for all binary values cannot exceed about 2.1 GB (see #MAX_TOTAL_BYTES_LENGTH).
• For sorted set fields, the sum of the size of each document's set of values cannot exceed about 2.1 B values (see #MAX_SORTED_SET_ORDS). For example, if every document has 10 values (10 instances of SortedSetDocValuesField) added, then no more than ~210 M documents can be added to one segment.

Field Summary

Fields

Modifier and Type	Field and Description
static int	MAX_SORTED_SET_ORDS The sum of the number of values across all documents in a sorted set field cannot exceed this.
static int	MAX_TOTAL_BYTES_LENGTH The sum of all byte lengths for binary field, or for the unique values in sorted or sorted set fields, cannot exceed this.

Constructor Summary

Constructors

Constructor and Description
DirectDocValuesFormat() Sole constructor.

Method Summary

Modifier and Type	Method and Description
DocValuesConsumer	fieldsConsumer(SegmentWriteState state) Returns a DocValuesConsumer to write docvalues to the index.
DocValuesProducer	fieldsProducer(SegmentReadState state) Returns a DocValuesProducer to read docvalues from the index.

Methods inherited from class org.apache.lucene.codecs.DocValuesFormat

availableDocValuesFormats, forName, getName, reloadDocValuesFormats, toString

Methods inherited from class java.lang.Object

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

Field Detail

MAX_TOTAL_BYTES_LENGTH

public static final int MAX_TOTAL_BYTES_LENGTH

The sum of all byte lengths for binary field, or for the unique values in sorted or sorted set fields, cannot exceed this.

MAX_SORTED_SET_ORDS

public static final int MAX_SORTED_SET_ORDS

The sum of the number of values across all documents in a sorted set field cannot exceed this.

Constructor Detail

DirectDocValuesFormat

public DirectDocValuesFormat()

Sole constructor.

Method Detail

fieldsConsumer

public DocValuesConsumer fieldsConsumer(SegmentWriteState state)
                                 throws IOException

Description copied from class: DocValuesFormat

Returns a DocValuesConsumer to write docvalues to the index.

Specified by:

fieldsConsumer in class DocValuesFormat

Throws:

IOException

fieldsProducer

public DocValuesProducer fieldsProducer(SegmentReadState state)
                                 throws IOException

Description copied from class: DocValuesFormat

Returns a DocValuesProducer to read docvalues from the index.

NOTE: by the time this call returns, it must hold open any files it will need to use; else, those files may be deleted. Additionally, required files may be deleted during the execution of this call before there is a chance to open them. Under these circumstances an IOException should be thrown by the implementation. IOExceptions are expected and will automatically cause a retry of the segment opening logic with the newly revised segments.

Specified by:

fieldsProducer in class DocValuesFormat

Throws:

IOException