Lucene 6 基于BKD Tree Index 的应用
keehang 发表了文章 • 0 个评论 • 6271 次浏览 • 2017-08-04 10:20
https://www.elastic.co/blog/lucene-points-6.0
Block k-d trees are a simple yet powerful data structure. At index time, they are built by recursively partitioning the full space of N-dimensional points to be indexed into smaller and smaller rectangular cells, splitting equally along the widest ranging dimension at each step of the recursion. However, unlike an ordinary k-d tree, a block k-d tree stops recursing once there are fewer than a pre-specified (1024 in our case, by default) number of points in the cell.
At that point, all points within that cell are written into one leaf block on disk and the starting file-pointer for that block is saved into an in-heap binary tree structure. In the 1D case, this is simply a full sort of all values, divided into adjacent leaf blocks. There are k-d tree variants that can support removing values, and rebalancing, but Lucene does not need these operations because of its write-once per-segment design.
At search time, the same recursion takes place, testing at each level whether the requested query shape intersects the left or right sub-tree of each dimensional split, and recursing if so. In the 1D case, the query shape is simply a numeric range whereas in the 2D and 3D cases, it is a geo-spatial shape (circle, ring, rectangle, polygon, cube, etc.).
测试集合:模拟一亿条
0," nnrIuS","raet","lnsr","inu ","saia",83.405273,73.302012,3991,24,"N"," usA","airport","rra i"
1,"omlritp","aaVe","y Mu","AaVV","NMc ",15.459643,-20.826241,2627,54,"a","eemo","airport","MaArp"
2,"kyaneMr","iasm","raAA"," tnt","inls",16.606066,38.663728,2761,53,"o","arIi","airport","uiron"
1. General Multidimensional Space Points
Search for points with exact given values.
Search for points which has one of the value from a given set of values.
Search for points within a given range.
Get the number of points which has exact point.
Get the number of points within a given range. (Ranges are multidimensional ranges. In 3D, they are boxes.)
Divide points into range-buckets and get the count in each buckets. (Range bucket is a range which has a label in it)
2. Locations on the planet surface. (Latitude, Longitude)
Find closest set of airports to a given town.
Find the set of airports within a given radius from a particular town.
Find the set of airports inside a country. (Country can be given as a polygon)
Find the set of airports within a given range of Latitudes and Longitudes. It is a Latitude, Longitude box query. (For a examples: Airports closer to the equatorial)
Find the set of airports closer to a given path. (Path can be something like a road. Find the airports which are less than 50km away from a given highway)
Count the airports in each country by giving country maps as polygons.
search result:
Loading Data is finished ----------------------------------------------------------------------
建索引花费时间:982ms
LatLon - Box Query Example------------------------------------------------------------------------------
search_LatLon_Box 花费时间:69ms
LatLon - K Nearest------------------------------------------------------------------------------
search_LatLon_Nearest 花费时间:108ms
DoublePoint 1D Point Exact------------------------------------------------------------------------------
search_Double_1D_Exact 花费时间:10ms
DoublePoint 1D - Range------------------------------------------------------------------------------
search_Double_1D_range 花费时间:8ms
DoublePoint 1D - Range Buckets -----------------------------------------------------------------------------
search_Double_1D_range_bucket 花费时间:58ms
DoublePoint multi dimensional - Range------------------------------------------------------------------------------
search_Double_MiltiDimensional_Range 花费时间:1ms
elasticsearch 使用scroll查询,为什么每次查询结果相同
yangg 回复了问题 • 3 人关注 • 3 个回复 • 4392 次浏览 • 2017-08-05 03:34
每天一小问:Elastic中doc_values VS fielddata
回复ElastIcPG 发起了问题 • 1 人关注 • 0 个回复 • 2432 次浏览 • 2017-08-03 19:49
ElasticSearch中怎么对搜索结果集进行复杂的逻辑过滤?
xinfanwang 回复了问题 • 7 人关注 • 6 个回复 • 5286 次浏览 • 2017-11-02 10:45
es 返回文档中如何看是由哪个搜索词搜出的
colie 回复了问题 • 2 人关注 • 2 个回复 • 2306 次浏览 • 2017-08-03 16:07
一台服务器64G内存,100亿条数据,全文查能优化到30秒内吗
novia 回复了问题 • 2 人关注 • 1 个回复 • 3641 次浏览 • 2017-08-03 16:03
又一次遇到这种问题,breakers.request内存溢出
kennywu76 回复了问题 • 4 人关注 • 1 个回复 • 3443 次浏览 • 2017-08-04 10:42
elasticsearch安装在windows上,
wangshuoqiong 回复了问题 • 3 人关注 • 2 个回复 • 2793 次浏览 • 2017-10-09 11:25
elastic官方文档关于consistency策略验证疑问
kennywu76 回复了问题 • 2 人关注 • 2 个回复 • 5594 次浏览 • 2017-08-03 12:52
elasticsearch索引自动生成映射?
sdoheji1234 回复了问题 • 2 人关注 • 3 个回复 • 3812 次浏览 • 2017-08-03 11:19
Java调用 Fielddata is disabled on text fields by default Set fielddata=true on [geoip.city_name]
回复clean 发起了问题 • 1 人关注 • 0 个回复 • 10053 次浏览 • 2017-08-02 17:58