elasticsearch 口水篇 Facet

FACET

1)Terms Facet

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{
     "query"  : {
         "match_all"  : {  }
     },
     "facets"  : {
         "tag"  : {
             "terms"  : {
                 "field"  "tag" ,
                 "size"  10
             }
         }
     }
}

被统计(facet)的字段一般不分词(例如商品的类目字段——类目唯一),但也支持分词后term不多的字段(例如商品的标签字段)。  

对应这种facet我们主要关注几点:

facet的字段(field,multi fields)

facet返回的数量(top N)

facet排序(count,term,reverse_count,reverse_term)

facet作用范围(all terms,excluding terms,regex patterns,term script)

 

2)Range Facets

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{
     "query"  : {
         "match_all"  : {}
     },
     "facets"  : {
         "range1"  : {
             "range"  : {
                 "field"  "field_name" ,
                 "ranges"  : [
                     "to"  50  },
                     "from"  50 "to"  70  },
                     "from"  70 "to"  120  },
                     "from"  120  }
                 ]
             }
         }
     }
}

例如:

商品的价格区间。

考虑下面一种需求:

统计各个价格区间购买次数。(每个商品有个销量字段)

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{
     "query"  : {
         "match_all"  : {}
     },
     "facets"  : {
         "range1"  : {
             "range"  : {
                 "key_field"  "price" ,
                 "value_field"  "volume" ,
                 "ranges"  : [
                     "to"  50  },
                     "from"  50 "to"  70  },
                     "from"  70 "to"  120  },
                     "from"  120  }
                 ]
             }
         }
     }
}

 

3)Histogram Facet

实现直方图的效果,其实也算是range的一种。

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{
     "query"  : {
         "match_all"  : {}
     },
     "facets"  : {
         "histo1"  : {
             "histogram"  : {
                 "field"  "field_name" ,
                 "interval"  100
             }
         }
     }
}

interval可以理解为步长。除了number型还有time_interval。  

 

4)Date Histogram Facet

 

 

5)Filter Facets

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{
     "facets"  : {
         "wow_facet"  : {
             "filter"  : {
                 "term"  : {  "tag"  "wow"  }
             }
         }
     }
}

返回命中“指定filter”的结果数。

 

6)Query Facets

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{
     "facets"  : {
         "wow_facet"  : {
             "query"  : {
                 "term"  : {  "tag"  "wow"  }
             }
         }
     }
}

Q:FilterFacets VS. QueryFacets?

 

7)Statistical Facet

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{
     "query"  : {
         "match_all"  : {}
     },
     "facets"  : {
         "stat1"  : {
             "statistical"  : {
                 "field"  "num1"
             }
         }
     }
}

StatisticalFacet需要作用在数值型字段上面,他会统计总数、总和、最值、均值等。

 

 8)Terms stats Facet

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{
     "query"  : {
         "match_all"  : {  }
     },
     "facets"  : {
         "tag_price_stats"  : {
             "terms_stats"  : {
                 "key_field"  "tag" ,
                 "value_field"  "price"
             }
         }
     }
}

也是一个kv的统计,例如统计某某类目下价格的分布情况(最值、均值等)。

 

9)GEO distance Facet

 

--------------------------------------------------

 javaClient Demo:

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public  void  facet() {
         SearchResponse sr = client.prepareSearch()
                 .setQuery(QueryBuilders.matchAllQuery())
                 .addFacet(FacetBuilders.termsFacet( "f1" ).field( "price" ))
                 .execute().actionGet();
 
         // Get your facet results
         TermsFacet f = (TermsFacet) sr.getFacets().facetsAsMap().get( "f1" );
 
         System.out.println(f.getTotalCount());  // Total terms doc count
         System.out.println(f.getOtherCount());  // Not shown terms doc count
         System.out.println(f.getMissingCount());  // Without term doc count
 
         // For each entry
         for  (TermsFacet.Entry entry : f) {
             System.out.println( "t:"  + entry.getTerm());  // Term
             System.out.println( "c:"  + entry.getCount());  // Doc count
             System.out.println( "----" );
         }
     }

  http://www.cnblogs.com/huangfox/p/3636604.html

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转载自m635674608.iteye.com/blog/2263241