org.apache.lucene.bkdtree

Class BKDTreeDocValuesFormat

java.lang.Object

org.apache.lucene.codecs.DocValuesFormat

org.apache.lucene.bkdtree.BKDTreeDocValuesFormat

All Implemented Interfaces:

NamedSPILoader.NamedSPI

Deprecated.

Use dimensional values in Lucene 6.0 instead

@Deprecated
public class BKDTreeDocValuesFormat
extends DocValuesFormat

A DocValuesFormat to efficiently index geo-spatial lat/lon points from BKDPointField for fast bounding-box (BKDPointInBBoxQuery) and polygon (BKDPointInPolygonQuery) queries.

This wraps Lucene54DocValuesFormat, but saves its own BKD tree structures to disk for fast query-time intersection. See this paper for details.

The BKD tree slices up 2D (lat/lon) space into smaller and smaller rectangles, until the smallest rectangles have approximately between X/2 and X (X default is 1024) points in them, at which point such leaf cells are written as a block to disk, while the index tree structure records how space was sub-divided is loaded into HEAP at search time. At search time, the tree is recursed based on whether each of left or right child overlap with the query shape, and once a leaf block is reached, all documents in that leaf block are collected if the cell is fully enclosed by the query shape, or filtered and then collected, if not.

The index is also quite compact, because docs only appear once in the tree (no "prefix terms").

In addition to the files written by Lucene54DocValuesFormat, this format writes:

1. .kdd: BKD leaf data and index
2. .kdm: BKD metadata

The disk format is experimental and free to change suddenly, and this code likely has new and exciting bugs!

WARNING: This API is experimental and might change in incompatible ways in the next release.

Constructor Summary

Constructors

Constructor and Description
BKDTreeDocValuesFormat() Deprecated. Default constructor
BKDTreeDocValuesFormat(int maxPointsInLeafNode, int maxPointsSortInHeap) Deprecated. Creates this with custom configuration.

Method Summary

Methods

Modifier and Type	Method and Description
DocValuesConsumer	fieldsConsumer(SegmentWriteState state) Deprecated.
DocValuesProducer	fieldsProducer(SegmentReadState state) Deprecated.

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

Constructor Detail

BKDTreeDocValuesFormat

public BKDTreeDocValuesFormat()

Deprecated.

Default constructor

BKDTreeDocValuesFormat

public BKDTreeDocValuesFormat(int maxPointsInLeafNode,
                      int maxPointsSortInHeap)

Deprecated.

Creates this with custom configuration.

Parameters:

maxPointsInLeafNode - Maximum number of points in each leaf cell. Smaller values create a deeper tree with larger in-heap index and possibly faster searching. The default is 1024.

maxPointsSortInHeap - Maximum number of points where in-heap sort can be used. When the number of points exceeds this, a (slower) offline sort is used. The default is 128 * 1024.

WARNING: This API is experimental and might change in incompatible ways in the next release.

Method Detail

fieldsConsumer

public DocValuesConsumer fieldsConsumer(SegmentWriteState state)
                                 throws IOException

Deprecated.

Specified by:

fieldsConsumer in class DocValuesFormat

Throws:

IOException

fieldsProducer

public DocValuesProducer fieldsProducer(SegmentReadState state)
                                 throws IOException

Deprecated.

Specified by:

fieldsProducer in class DocValuesFormat

Throws:

IOException