elasticsearch—深入聚合分析

Bucket & Metric 聚合分析及嵌套聚合

Aggregation 的语法

Aggregation 属于 Search 的一部分。一般情况下，建议将其 Size 指定为 0

Metric Aggregation

⼀个例⼦：⼯资统计信息

插入数据

DELETE /employees
PUT /employees/
{
  "mappings": {
    "properties": {
      "age": {
        "type": "integer"
      },
      "gender": {
        "type": "keyword"
      },
      "job": {
        "type": "text",
        "fields": {
          "keyword": {
            "type": "keyword",
            "ignore_above": 50
          }
        }
      },
      "name": {
        "type": "keyword"
      },
      "salary": {
        "type": "integer"
      }
    }
  }
}

PUT /employees/_bulk
{ "index" : {  "_id" : "1" } }
{ "name" : "Emma","age":32,"job":"Product Manager","gender":"female","salary":35000 }
{ "index" : {  "_id" : "2" } }
{ "name" : "Underwood","age":41,"job":"Dev Manager","gender":"male","salary": 50000}
{ "index" : {  "_id" : "3" } }
{ "name" : "Tran","age":25,"job":"Web Designer","gender":"male","salary":18000 }
{ "index" : {  "_id" : "4" } }
{ "name" : "Rivera","age":26,"job":"Web Designer","gender":"female","salary": 22000}
{ "index" : {  "_id" : "5" } }
{ "name" : "Rose","age":25,"job":"QA","gender":"female","salary":18000 }
{ "index" : {  "_id" : "6" } }
{ "name" : "Lucy","age":31,"job":"QA","gender":"female","salary": 25000}
{ "index" : {  "_id" : "7" } }
{ "name" : "Byrd","age":27,"job":"QA","gender":"male","salary":20000 }
{ "index" : {  "_id" : "8" } }
{ "name" : "Foster","age":27,"job":"Java Programmer","gender":"male","salary": 20000}
{ "index" : {  "_id" : "9" } }
{ "name" : "Gregory","age":32,"job":"Java Programmer","gender":"male","salary":22000 }
{ "index" : {  "_id" : "10" } }
{ "name" : "Bryant","age":20,"job":"Java Programmer","gender":"male","salary": 9000}
{ "index" : {  "_id" : "11" } }
{ "name" : "Jenny","age":36,"job":"Java Programmer","gender":"female","salary":38000 }
{ "index" : {  "_id" : "12" } }
{ "name" : "Mcdonald","age":31,"job":"Java Programmer","gender":"male","salary": 32000}
{ "index" : {  "_id" : "13" } }
{ "name" : "Jonthna","age":30,"job":"Java Programmer","gender":"female","salary":30000 }
{ "index" : {  "_id" : "14" } }
{ "name" : "Marshall","age":32,"job":"Javascript Programmer","gender":"male","salary": 25000}
{ "index" : {  "_id" : "15" } }
{ "name" : "King","age":33,"job":"Java Programmer","gender":"male","salary":28000 }
{ "index" : {  "_id" : "16" } }
{ "name" : "Mccarthy","age":21,"job":"Javascript Programmer","gender":"male","salary": 16000}
{ "index" : {  "_id" : "17" } }
{ "name" : "Goodwin","age":25,"job":"Javascript Programmer","gender":"male","salary": 16000}
{ "index" : {  "_id" : "18" } }
{ "name" : "Catherine","age":29,"job":"Javascript Programmer","gender":"female","salary": 20000}
{ "index" : {  "_id" : "19" } }
{ "name" : "Boone","age":30,"job":"DBA","gender":"male","salary": 30000}
{ "index" : {  "_id" : "20" } }
{ "name" : "Kathy","age":29,"job":"DBA","gender":"female","salary": 20000}

View Code

Metric 聚合，找到最低的工资

POST employees/_search
{
  "size": 0,
  "aggs": {
    "min_salary": {
      "min": {
        "field": "salary"
      }
    }
  }
}

Metric 聚合，找到最高的工资

POST employees/_search
{
  "size": 0,
  "aggs": {
    "max_salary": {
      "max": {
        "field": "salary"
      }
    }
  }
}

多个 Metric 聚合，找到最低最高和平均工资

POST employees/_search
{
  "size": 0,
  "aggs": {
    "max_salary": {
      "max": {
        "field": "salary"
      }
    },
    "min_salary": {
      "min": {
        "field": "salary"
      }
    },
    "avg_salary": {
      "avg": {
        "field": "salary"
      }
    }
  }
}

一个聚合，输出多值

POST employees/_search
{
  "size": 0,
  "aggs": {
    "stats_salary": {
      "stats": {
        "field": "salary"
      }
    }
  }
}

Bucket

Terms Aggregation

字段需要打开 fielddata，才能进⾏ Terms Aggregation　　

Keyword 默认⽀持 doc_values　
Text 需要在 Mapping 中 enable。会按照分词后的结果进⾏分

对 job 和 job.keyword 进⾏聚合

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword"
      }
    }
  }
}

对 Text 字段进行 terms 聚合查询，失败

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job"
      }
    }
  }
}

对 Text 字段打开 fielddata，支持terms aggregation

PUT employees/_mapping
{
  "properties": {
    "job": {
      "type": "text",
      "fielddata": true
    }
  }
}

View Code

对 Text 字段进行 terms 分词。分词后的terms

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job"
      }
    }
  }
}

Cardinality

类似 SQL 中的 Distinct count （去重分组数量）

POST employees/_search
{
  "size": 0,
  "aggs": {
    "cardinate": {
      "cardinality": {
        "field": "job.keyword"
      }
    }
  }
}

Bucket Size & Top Hits Demo

应⽤场景：当获取分桶后，桶内最匹配的顶部⽂档列表

Size：按年龄分桶，找出指定数据量的分桶信息，只获取分组后的前三组

POST employees/_search
{
  "size": 0,
  "aggs": {
    "ages_5": {
      "terms": {
        "field": "age",
        "size": 3
      }
    }
  }
}

Top Hits：查看各个⼯种中，年纪最⼤的 3 名员⼯

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword"
      },
      "aggs": {
        "old_employee": {
          "top_hits": {
            "size": 3,
            "_source": ["name", "job"], 
            "sort": [
              {
                "age": {
                  "order": "desc"
                }
              }
            ]
          }
        }
      }
    }
  }
}

Range & Histogram 聚合

按照数字的范围，进⾏分桶，在 Range Aggregation 中，可以⾃定义 Key

POST employees/_search
{
  "size": 0,
  "aggs": {
    "salary_range": {
      "range": {
        "field": "salary",
        "ranges": [
          {
            "to": 10000
          },
          {
            "from": 10000,
            "to": 20000
          },
          {
            "key": ">20000",
            "from": 20000
          }
        ]
      }
    }
  }
}

按照⼯资的间隔（Histogram）分桶，Salary Histogram,工资0到10万，以 5000一个区间进行分桶　　

POST employees/_search
{
  "size": 0,
  "aggs": {
    "salary_histrogram": {
      "histogram": {
        "field": "salary",
        "interval": 5000,
        "extended_bounds": {
          "min": 0,
          "max": 100000
        }
      }
    }
  }
}

Bucket + Metric Aggregation

Bucket 聚合分析允许通过添加⼦聚合分析来进⼀步分析，⼦聚合分析可以是　　

Bucket
Metric

嵌套聚合1 按照工作类型分桶，并统计工资信息　　

POST employees/_search
{
  "size": 0,
  "aggs": {
    "Job_salary_stats": {
      "terms": {
        "field": "job.keyword"
      },
      "aggs": {
        "salary": {
          "stats": {
            "field": "salary"
          }
        }
      }
    }
  }
}

多次嵌套，根据工作类型分桶，然后按照性别分桶，计算工资的统计信息

POST employees/_search
{
  "size": 0,
  "aggs": {
    "Job_gender_stats": {
      "terms": {
        "field": "job.keyword"
      },
      "aggs": {
        "gender_stats": {
          "terms": {
            "field": "gender"
          },
          "aggs": {
            "salary_stats": {
              "stats": {
                "field": "salary"
              }
            }
          }
        }
      }
    }
  }
}

Pipeline 聚合分析

管道的概念: ⽀持对聚合分析的结果，再次进⾏聚合分析

Pipeline 的分析结果会输出到原结果中，根据位置的不同，分为两类

Sibling - 结果和现有分析结果同级

Max，min，Avg & Sum Bucket

Stats，Extended Status Bucket

Percentiles Bucket

Parent - 结果内嵌到现有的聚合分析结果之中

Cumultive Sum （累计求和）

Derivative （求导）

Moving Function (滑动窗⼝)

数据导入

DELETE employees
PUT /employees/_bulk
{ "index" : {  "_id" : "1" } }
{ "name" : "Emma","age":32,"job":"Product Manager","gender":"female","salary":35000 }
{ "index" : {  "_id" : "2" } }
{ "name" : "Underwood","age":41,"job":"Dev Manager","gender":"male","salary": 50000}
{ "index" : {  "_id" : "3" } }
{ "name" : "Tran","age":25,"job":"Web Designer","gender":"male","salary":18000 }
{ "index" : {  "_id" : "4" } }
{ "name" : "Rivera","age":26,"job":"Web Designer","gender":"female","salary": 22000}
{ "index" : {  "_id" : "5" } }
{ "name" : "Rose","age":25,"job":"QA","gender":"female","salary":18000 }
{ "index" : {  "_id" : "6" } }
{ "name" : "Lucy","age":31,"job":"QA","gender":"female","salary": 25000}
{ "index" : {  "_id" : "7" } }
{ "name" : "Byrd","age":27,"job":"QA","gender":"male","salary":20000 }
{ "index" : {  "_id" : "8" } }
{ "name" : "Foster","age":27,"job":"Java Programmer","gender":"male","salary": 20000}
{ "index" : {  "_id" : "9" } }
{ "name" : "Gregory","age":32,"job":"Java Programmer","gender":"male","salary":22000 }
{ "index" : {  "_id" : "10" } }
{ "name" : "Bryant","age":20,"job":"Java Programmer","gender":"male","salary": 9000}
{ "index" : {  "_id" : "11" } }
{ "name" : "Jenny","age":36,"job":"Java Programmer","gender":"female","salary":38000 }
{ "index" : {  "_id" : "12" } }
{ "name" : "Mcdonald","age":31,"job":"Java Programmer","gender":"male","salary": 32000}
{ "index" : {  "_id" : "13" } }
{ "name" : "Jonthna","age":30,"job":"Java Programmer","gender":"female","salary":30000 }
{ "index" : {  "_id" : "14" } }
{ "name" : "Marshall","age":32,"job":"Javascript Programmer","gender":"male","salary": 25000}
{ "index" : {  "_id" : "15" } }
{ "name" : "King","age":33,"job":"Java Programmer","gender":"male","salary":28000 }
{ "index" : {  "_id" : "16" } }
{ "name" : "Mccarthy","age":21,"job":"Javascript Programmer","gender":"male","salary": 16000}
{ "index" : {  "_id" : "17" } }
{ "name" : "Goodwin","age":25,"job":"Javascript Programmer","gender":"male","salary": 16000}
{ "index" : {  "_id" : "18" } }
{ "name" : "Catherine","age":29,"job":"Javascript Programmer","gender":"female","salary": 20000}
{ "index" : {  "_id" : "19" } }
{ "name" : "Boone","age":30,"job":"DBA","gender":"male","salary": 30000}
{ "index" : {  "_id" : "20" } }
{ "name" : "Kathy","age":29,"job":"DBA","gender":"female","salary": 20000}

View Code

Sibling 例子

平均工资最低的工作类型

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword",
        "size": 10
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        }
      }
    },
    "min_salary_by_job": {
      "min_bucket": {
        "buckets_path": "jobs>avg_salary"
      }
    }
  }
}

平均工资最高的工作类型

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword",
        "size": 10
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        }
      }
    },
    "max_salary_by_job": {
      "max_bucket": {
        "buckets_path": "jobs>avg_salary"
      }
    }
  }
}

平均工资的平均工资

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword",
        "size": 10
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        }
      }
    },
    "avg_salary_by_job": {
      "avg_bucket": {
        "buckets_path": "jobs>avg_salary"
      }
    }
  }
}

平均工资的统计分析　　

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword",
        "size": 10
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        }
      }
    },
    "stats_salary_by_job": {
      "stats_bucket": {
        "buckets_path": "jobs>avg_salary"
      }
    }
  }
}

平均工资的百分位数　　

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword",
        "size": 10
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        }
      }
    },
    "percentiles_salary_by_job":{
      "percentiles_bucket": {
        "buckets_path": "jobs>avg_salary"
      }
    }
  }
}

Parent Derivative　

按照年龄对平均工资求导

POST employees/_search
{
  "size": 0,
  "aggs": {
    "age": {
      "histogram": {
        "field": "age",
        "min_doc_count": 1,
        "interval": 1
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        },
        "derivative_avg_salary": {
          "derivative": {
            "buckets_path": "avg_salary"
          }
        }
      }
    }
  }
}

聚合的作⽤范围及排序

聚合的作⽤范围　　

ES 聚合分析的默认作⽤范围是 query 的查询结果集　

同时 ES 还⽀持以下⽅式改变聚合的作⽤范围　

Filter
Post_Filter
Global

导入数据

DELETE /employees
PUT /employees/
{
  "mappings": {
    "properties": {
      "age": {
        "type": "integer"
      },
      "gender": {
        "type": "keyword"
      },
      "job": {
        "type": "text",
        "fields": {
          "keyword": {
            "type": "keyword",
            "ignore_above": 50
          }
        }
      },
      "name": {
        "type": "keyword"
      },
      "salary": {
        "type": "integer"
      }
    }
  }
}

PUT /employees/_bulk
{ "index" : {  "_id" : "1" } }
{ "name" : "Emma","age":32,"job":"Product Manager","gender":"female","salary":35000 }
{ "index" : {  "_id" : "2" } }
{ "name" : "Underwood","age":41,"job":"Dev Manager","gender":"male","salary": 50000}
{ "index" : {  "_id" : "3" } }
{ "name" : "Tran","age":25,"job":"Web Designer","gender":"male","salary":18000 }
{ "index" : {  "_id" : "4" } }
{ "name" : "Rivera","age":26,"job":"Web Designer","gender":"female","salary": 22000}
{ "index" : {  "_id" : "5" } }
{ "name" : "Rose","age":25,"job":"QA","gender":"female","salary":18000 }
{ "index" : {  "_id" : "6" } }
{ "name" : "Lucy","age":31,"job":"QA","gender":"female","salary": 25000}
{ "index" : {  "_id" : "7" } }
{ "name" : "Byrd","age":27,"job":"QA","gender":"male","salary":20000 }
{ "index" : {  "_id" : "8" } }
{ "name" : "Foster","age":27,"job":"Java Programmer","gender":"male","salary": 20000}
{ "index" : {  "_id" : "9" } }
{ "name" : "Gregory","age":32,"job":"Java Programmer","gender":"male","salary":22000 }
{ "index" : {  "_id" : "10" } }
{ "name" : "Bryant","age":20,"job":"Java Programmer","gender":"male","salary": 9000}
{ "index" : {  "_id" : "11" } }
{ "name" : "Jenny","age":36,"job":"Java Programmer","gender":"female","salary":38000 }
{ "index" : {  "_id" : "12" } }
{ "name" : "Mcdonald","age":31,"job":"Java Programmer","gender":"male","salary": 32000}
{ "index" : {  "_id" : "13" } }
{ "name" : "Jonthna","age":30,"job":"Java Programmer","gender":"female","salary":30000 }
{ "index" : {  "_id" : "14" } }
{ "name" : "Marshall","age":32,"job":"Javascript Programmer","gender":"male","salary": 25000}
{ "index" : {  "_id" : "15" } }
{ "name" : "King","age":33,"job":"Java Programmer","gender":"male","salary":28000 }
{ "index" : {  "_id" : "16" } }
{ "name" : "Mccarthy","age":21,"job":"Javascript Programmer","gender":"male","salary": 16000}
{ "index" : {  "_id" : "17" } }
{ "name" : "Goodwin","age":25,"job":"Javascript Programmer","gender":"male","salary": 16000}
{ "index" : {  "_id" : "18" } }
{ "name" : "Catherine","age":29,"job":"Javascript Programmer","gender":"female","salary": 20000}
{ "index" : {  "_id" : "19" } }
{ "name" : "Boone","age":30,"job":"DBA","gender":"male","salary": 30000}
{ "index" : {  "_id" : "20" } }
{ "name" : "Kathy","age":29,"job":"DBA","gender":"female","salary": 20000}

View Code

查询年龄大于20的，按照job分组

POST employees/_search
{
  "size": 0,
  "query": {
    "range": {
      "age": {
        "gte": 20
      }
    }
  },
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword"
      }
    }
  }
}

Filter　　

POST employees/_search
{
  "size": 0,
  "aggs": {
    "older_person": {
      "filter": {
        "range": {
          "age": {
            "from": 35
          }
        }
      },
      "aggs": {
        "jobs": {
          "terms": {
            "field": "job.keyword"
          }
        }
      }
    },
    "all_jobs": {
      "terms": {
        "field": "job.keyword"
      }
    }
  }
}

输出结果如下　　

{
  "took" : 2,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 20,
      "relation" : "eq"
    },
    "max_score" : null,
    "hits" : [ ]
  },
  "aggregations" : {
    "older_person" : {
      "doc_count" : 2,
      "jobs" : {
        "doc_count_error_upper_bound" : 0,
        "sum_other_doc_count" : 0,
        "buckets" : [
          {
            "key" : "Dev Manager",
            "doc_count" : 1
          },
          {
            "key" : "Java Programmer",
            "doc_count" : 1
          }
        ]
      }
    },
    "all_jobs" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "Java Programmer",
          "doc_count" : 7
        },
        {
          "key" : "Javascript Programmer",
          "doc_count" : 4
        },
        {
          "key" : "QA",
          "doc_count" : 3
        },
        {
          "key" : "DBA",
          "doc_count" : 2
        },
        {
          "key" : "Web Designer",
          "doc_count" : 2
        },
        {
          "key" : "Dev Manager",
          "doc_count" : 1
        },
        {
          "key" : "Product Manager",
          "doc_count" : 1
        }
      ]
    }
  }
}

View Code

Post_Filter

是对聚合分析后的⽂档进⾏再次过滤
Size ⽆需设置为 0

使⽤场景

⼀条语句，获取聚合信息 + 获取符合条件的⽂档

一条语句，找出所有的job分组。还能找到job为 dev manager的所有数据

POST employees/_search
{
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword"
      }
    }
  },
  "post_filter": {
    "match": {
      "job.keyword": "Dev Manager"
    }
  }
}

Global

⽆视 query，对全部⽂档进⾏统计

POST employees/_search
{
  "size": 0,
  "query": {
    "range": {
      "age": {
        "gte": 40
      }
    }
  },
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword"
      }
    },
    "all": {
      "global": {},
      "aggs": {
        "salary_avg": {
          "avg": {
            "field": "salary"
          }
        }
      }
    }
  }
}

排序

指定 order，按照 count 和 key 进⾏排序

默认情况，按照 count 降序排序
指定 size，就能返回相应的桶

POST employees/_search
{
  "size": 0,
  "query": {
    "range": {
      "age": {
        "gte": 20
      }
    }
  },
  "aggs": {
    "jobs": {
      "terms": {
        "field": "job.keyword",
        "order": [
          {
            "_count": "asc"
          },
          {
            "_key": "desc"
          }
        ]
      }
    }
  }
}

基于⼦聚合的值排序

基于⼦聚合的数值进⾏排序
使⽤⼦聚合，Aggregation name

POST employees/_search
{
  "size": 0,
  "aggs": {
    "jobs": {
      "terms": {
        "field":"job.keyword",
        "order":[  {
            "stats_salary.min":"desc"
          }]
        
        
      },
    "aggs": {
      "stats_salary": {
        "stats": {
          "field":"salary"
        }
      }
    }
    }
  }
}

聚合的精准度问题　　

Terms Aggregation 的返回值

如何解决 Terms 不准的问题：提升 shard_size 的参数

Terms 聚合分析不准的原因，数据分散在多个分⽚上， Coordinating Node ⽆法获取数据全貌

解决⽅案

1：当数据量不⼤时，设置 Primary Shard 为 1；实现准确性
2：在分布式数据上，设置 shard_size 参数，提⾼精确度，原理：每次从 Shard 上额外多获取数据，提升准确率

调整 shard size ⼤⼩，降低 doc_count_error_upper_bound 来提升准确度，增加整体计算量，提⾼了准确度，但会降低相应时间

Shard Size 默认⼤⼩设定

shard size = size *1.5 +10
https://www.elastic.co/guide/en/elasticsearch/reference/7.2/search-aggregations-bucket-terms-aggregation.html

例子

GET my_flights/_search
{
  "size": 0,
  "aggs": {
    "weather": {
      "terms": {
        "field":"OriginWeather",
        "size":1,
        "shard_size":10,
        "show_term_doc_count_error":true
      }
    }
  }
}

Composite 聚合—— 多条件聚合后分页实现

POST legislation/_search
{
  "size": 0,
  "query": {
    "term": {
      "source_type": {
        "value": "migrate"
      }
    }
  },
  "aggs": {
    "legislation": {
      "composite": {
        "sources": [
          {
            "norm_citation": {
              "terms": {
                "field": "norm_citation"
              }
            }
          },
          {
            "designator": {
              "terms": {
                "field": "designator.keyword"
              }
            }
          }
        ],
        "size": 10
      }
    }
  }
}

POST legislation/_search
{
  "size": 0,
  "query": {
    "term": {
      "source_type": {
        "value": "migrate"
      }
    }
  },
  "aggs": {
    "legislation": {
      "composite": {
        "sources": [
          {
            "norm_citation": {
              "terms": {
                "field": "norm_citation"
              }
            }
          },
          {
            "designator": {
              "terms": {
                "field": "designator.keyword"
              }
            }
          }
        ],
        "size": 10, 
        "after": {
          "norm_citation": "1890_39a",
          "designator": "section-15"
        }
      }
    }
  }
}

posted @ 2021-04-02 15:29 Crazymagic 阅读(160) 评论(0) 编辑收藏举报

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Crazymagic

elasticsearch—深入聚合分析

Bucket & Metric 聚合分析及嵌套聚合

Metric Aggregation

Bucket

Bucket Size & Top Hits Demo

Range & Histogram 聚合

Bucket + Metric Aggregation

相关阅读

Pipeline 聚合分析

Sibling 例子

聚合的作⽤范围及排序

聚合的作⽤范围

排序

聚合的精准度问题

如何解决 Terms 不准的问题：提升 shard_size 的参数

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