[Elastic][Elasticsearch] Nested 필드 타입

설명

• 배열 형태의 데이터에 대해 개별 query 및 aggregations을 하기 위한 필드 타입

테스트

• 데이터

   PUT index_1/_doc/1
   {
     "array_1": [
       {
         "name": "name 1",
         "date": "2021/01/01 01:00:00",
         "array_2": [
           {
             "field_1": "1",
             "field_2": 1
           },
           {
             "field_1": "2",
             "field_2": 2
           }
         ]
       }
     ]
   }
  

• Nested를 지정하지 않은 경우
  • request

     GET index_1/_search
     {
     "query": {
       "range": {
         "array_1.date": {
           "gte": "2021/01/01 01:00:00",
           "lt": "2021/01/01 01:05:00",
           "format": "yyyy/MM/dd HH:mm:ss"
         }
       }
     },
     "size": 0,
     "aggs": {
       "name": {
         "terms": {
           "field": "array_1.name.keyword"
         },
         "aggs": {
           "array_2-field_1": {
             "terms": {
               "field": "array_1.array_2.field_1.keyword"
             },
             "aggs": {
               "array_2-field_2": {
                 "stats": {
                   "field": "array_1.array_2.field_2"
                 }
               }
             }
           }
         }
       }
     }
     }
    

  • response
    • terms를 지정하였음에도 모든 field_2에 대해 연산 수행

       {
       "took" : 3,
       "timed_out" : false,
       "_shards" : {
       "total" : 1,
       "successful" : 1,
       "skipped" : 0,
       "failed" : 0
       },
       "hits" : {
       "total" : {
         "value" : 1,
         "relation" : "eq"
       },
       "max_score" : null,
       "hits" : [ ]
       },
       "aggregations" : {
       "name" : {
         "doc_count_error_upper_bound" : 0,
         "sum_other_doc_count" : 0,
         "buckets" : [
           {
             "key" : "name 1",
             "doc_count" : 1,
             "array_2-field_1" : {
               "doc_count_error_upper_bound" : 0,
               "sum_other_doc_count" : 0,
               "buckets" : [
                 {
                   "key" : "1",
                   "doc_count" : 1,
                   "array_2-field_2" : {
                     "count" : 2,
                     "min" : 1.0,
                     "max" : 2.0,
                     "avg" : 1.5,
                     "sum" : 3.0
                   }
                 },
                 {
                   "key" : "2",
                   "doc_count" : 1,
                   "array_2-field_2" : {
                     "count" : 2,
                     "min" : 1.0,
                     "max" : 2.0,
                     "avg" : 1.5,
                     "sum" : 3.0
                   }
                 }
               ]
             }
           }
         ]
       }
       }
       }
      

• Nested를 지정한 경우
  • 정적 매핑

     PUT index_1
     {
     "mappings": {
       "properties": {
         "array_1": {
           "type": "nested",
           "properties": {
             "array_2": {
               "type": "nested",
               "properties": {
                 "field_1": {
                   "type": "text",
                   "fields": {
                     "keyword": {
                       "type": "keyword",
                       "ignore_above": 256
                     }
                   }
                 },
                 "field_2": {
                   "type": "long"
                 }
               }
             },
             "date": {
               "type": "date",
               "format": "yyyy/MM/dd HH:mm:ss||yyyy/MM/dd||epoch_millis"
             },
             "name": {
               "type": "text",
               "fields": {
                 "keyword": {
                   "type": "keyword",
                   "ignore_above": 256
                 }
               }
             }
           }
         }
       }
     }
     }
    

  • request

     GET index_1/_search
     {
     "query": {
       "nested": {
         "path": "array_1",
         "query": {
           "range": {
             "array_1.date": {
               "gte": "2021/01/01 01:00:00",
               "lt": "2021/01/01 01:05:00",
               "format": "yyyy/MM/dd HH:mm:ss"
             }
           }
         }
       }
     },
     "size": 0,
     "aggs": {
       "nested-array_1": {
         "nested": {
           "path": "array_1"
         },
         "aggs": {
           "name": {
             "terms": {
               "field": "array_1.name.keyword"
             },
             "aggs": {
               "nested-array_2": {
                 "nested": {
                   "path": "array_1.array_2"
                 },
                 "aggs": {
                   "array_2-field_1": {
                     "terms": {
                       "field": "array_1.array_2.field_1.keyword"
                     },
                     "aggs": {
                       "array_1-field_2": {
                         "stats": {
                           "field": "array_1.array_2.field_2"
                         }
                       }
                     }
                   }
                 }
               }
             }
           }
         }
       }
     }
     }
    

  • response

     {
     "took" : 2,
     "timed_out" : false,
     "_shards" : {
       "total" : 1,
       "successful" : 1,
       "skipped" : 0,
       "failed" : 0
     },
     "hits" : {
       "total" : {
         "value" : 1,
         "relation" : "eq"
       },
       "max_score" : null,
       "hits" : [ ]
     },
     "aggregations" : {
       "nested-array_1" : {
         "doc_count" : 1,
         "name" : {
           "doc_count_error_upper_bound" : 0,
           "sum_other_doc_count" : 0,
           "buckets" : [
             {
               "key" : "name 1",
               "doc_count" : 1,
               "nested-array_2" : {
                 "doc_count" : 2,
                 "array_2-field_1" : {
                   "doc_count_error_upper_bound" : 0,
                   "sum_other_doc_count" : 0,
                   "buckets" : [
                     {
                       "key" : "1",
                       "doc_count" : 1,
                       "array_1-field_2" : {
                         "count" : 1,
                         "min" : 1.0,
                         "max" : 1.0,
                         "avg" : 1.0,
                         "sum" : 1.0
                       }
                     },
                     {
                       "key" : "2",
                       "doc_count" : 1,
                       "array_1-field_2" : {
                         "count" : 1,
                         "min" : 2.0,
                         "max" : 2.0,
                         "avg" : 2.0,
                         "sum" : 2.0
                       }
                     }
                   ]
                 }
               }
             }
           ]
         }
       }
     }
     }