第二节 Pipeline 聚合分析
Pipeline aggregation——对分组+聚合继续再做分组+聚合。
1、一个例子:Pipeline:min_bucket
- 在员⼯数最多的⼯种里,找出平均工资最低的工种

2、Pipeline
- 管道的概念: ⽀持聚合分析的结果,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- Derivative (求导)
- Cumultive Sum (累计求和)
- Moving Function (滑动窗⼝)
 
 
- Sibling - 结果和现有分析结果同级
3、Sibling Pipeline 的例子
- 
对不同类型⼯作的,平均工资 
- 
求最⼤ 
- 平均
- 统计信息
- 百分位数
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}
3-1 min_bucket
平均工资最低的工作类型
# 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"
      }
    }
  }
}
- min_bucket
- jobs>avg_salary
Output
aggregations" : {
    "jobs" : {
      "doc_count_error_upper_bound" : 0,
      "sum_other_doc_count" : 0,
      "buckets" : [
        {
          "key" : "Java Programmer",
          "doc_count" : 7,
          "avg_salary" : {
            "value" : 25571.428571428572
          }
        },
        {
          "key" : "Javascript Programmer",
          "doc_count" : 4,
          "avg_salary" : {
            "value" : 19250.0
          }
        },
        {
          "key" : "QA",
          "doc_count" : 3,
          "avg_salary" : {
            "value" : 21000.0
          }
        },
        {
          "key" : "DBA",
          "doc_count" : 2,
          "avg_salary" : {
            "value" : 25000.0
          }
        },
        {
          "key" : "Web Designer",
          "doc_count" : 2,
          "avg_salary" : {
            "value" : 20000.0
          }
        },
        {
          "key" : "Dev Manager",
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 50000.0
          }
        },
        {
          "key" : "Product Manager",
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 35000.0
          }
        }
      ]
    },
    "min_salary_by_job" : {
      "value" : 19250.0,
      "keys" : [
        "Javascript Programmer"
      ]
    }
  }
3-2 max_bucket
# 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"
      }
    }
  }
}
Output :
...
"max_salary_by_job" : {
      "value" : 50000.0,
      "keys" : [
        "Dev Manager"
      ]
    }
  }
3-3 stats_bucket
# 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"
      }
    }
  }
}
Output
...
"stats_salary_by_job" : {
      "count" : 7,
      "min" : 19250.0,
      "max" : 50000.0,
      "avg" : 27974.48979591837,
      "sum" : 195821.42857142858
    }
3-4 percentiles_bucket
# 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"
      }
    }
  }
}
Output :
 "percentiles_salary_by_job" : {
      "values" : {
        "1.0" : 19250.0,
        "5.0" : 19250.0,
        "25.0" : 21000.0,
        "50.0" : 25000.0,
        "75.0" : 35000.0,
        "95.0" : 50000.0,
        "99.0" : 50000.0
      }
    }
  }
4、Parent Pipeline:Derivative
- 按照年龄,对⼯资进⾏求导(看⼯资发展的趋势)

5、Parent Pipeline 的例子
- 年龄直⽅图划分的平均工资- Cumulative Sum
- Moving Function
 
5-1 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": 0,
        "interval": 1
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        },
        "derivative_avg_salary":{
          "derivative": {
            "buckets_path": "avg_salary"
          }
        }
      }
    }
  }
}
Output
"aggregations" : {
    "age" : {
      "buckets" : [
        {
          "key" : 20.0,
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 9000.0
          }
        },
        {
          "key" : 21.0,
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 16000.0
          },
          "derivative_avg_salary" : {
            "value" : 7000.0
          }
        },
 ...
5-2 Cumulative_sum
#Cumulative_sum
POST employees/_search
{
  "size": 0,
  "aggs": {
    "age": {
      "histogram": {
        "field": "age",
        "min_doc_count": 0,
        "interval": 1
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        },
        "cumulative_salary":{
          "cumulative_sum": {
            "buckets_path": "avg_salary"
          }
        }
      }
    }
  }
}
Output :
  "aggregations" : {
    "age" : {
      "buckets" : [
        {
          "key" : 20.0,
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 9000.0
          },
          "cumulative_salary" : {
            "value" : 9000.0
          }
        },
        {
          "key" : 21.0,
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 16000.0
          },
          "cumulative_salary" : {
            "value" : 25000.0
          }
        },
        {
          "key" : 22.0,
          "doc_count" : 0,
          "avg_salary" : {
            "value" : null
          },
          "cumulative_salary" : {
            "value" : 25000.0
          }
        },
        ...
5-3 moving_fn
Moving Function也是一个Parent Pipeline Agg。它表示对于一个一定顺序的集合,维护一个窗口大小 N(当前 Bucket 往前的 N 个Buckets,支持用户自定义,默认不确定,待看,这里指定了是10),然后对这 N 个 Buckets 进行一个 Function 求解(默认值不确定,待看,支持用户自定义,这里我们定义了一个"script"类型的 Function:"MovingFunctions.min(values)" :表示对 "avg_salary"的结果"value"求最小值,也就是求窗口之内的 Bucket 的 Metric 最小值)。
#Moving Function
POST employees/_search
{
  "size": 0,
  "aggs": {
    "age": {
      "histogram": {
        "field": "age",
        "min_doc_count": 0,
        "interval": 1
      },
      "aggs": {
        "avg_salary": {
          "avg": {
            "field": "salary"
          }
        },
        "moving_avg_salary":{
          "moving_fn": {
            "buckets_path": "avg_salary",
            "window":10,
            "script": "MovingFunctions.min(values)"
          }
        }
      }
    }
  }
}
Ourtput
"aggregations" : {
    "age" : {
      "buckets" : [
        {
          "key" : 20.0,
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 9000.0
          },
          "moving_avg_salary" : {
            "value" : null
          }
        },
        {
          "key" : 21.0,
          "doc_count" : 1,
          "avg_salary" : {
            "value" : 16000.0
          },
          "moving_avg_salary" : {
            "value" : 9000.0
          }
        },
        {
          "key" : 22.0,
          "doc_count" : 0,
          "avg_salary" : {
            "value" : null
          }
        },
        ...
        "moving_avg_salary" : {
            "value" : 16000.0
          }