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« 正则表达式语法 桶聚合 »
Elastic 文档 ›Elasticsearch 指南 [8.17]

聚合

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聚合

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聚合将您的数据汇总为指标、统计数据或其他分析结果。聚合可以帮助您回答以下问题：

  • 我网站的平均加载时间是多少？
  • 基于交易量，我最有价值的客户是谁？
  • 在我的网络中，什么可以被认为是大型文件？
  • 每个产品类别中有多少种产品？

Elasticsearch 将聚合分为三个类别：

  • 指标 聚合，用于计算字段值的指标，例如总和或平均值。
  • 桶 聚合，用于根据字段值、范围或其他条件将文档分组到桶（也称为箱）中。
  • 管道 聚合，它从其他聚合而不是文档或字段获取输入。

运行聚合

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您可以通过指定 搜索 的 搜索 API 的 aggs 参数来运行聚合。以下搜索在 my-field 上运行 词项聚合

resp = client.search(
    index="my-index-000001",
    aggs={
        "my-agg-name": {
            "terms": {
                "field": "my-field"
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  body: {
    aggregations: {
      "my-agg-name": {
        terms: {
          field: 'my-field'
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  aggs: {
    "my-agg-name": {
      terms: {
        field: "my-field",
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search
{
  "aggs": {
    "my-agg-name": {
      "terms": {
        "field": "my-field"
      }
    }
  }
}
Copy as curlTry in Elastic 

聚合结果位于响应的 aggregations 对象中

{
  "took": 78,
  "timed_out": false,
  "_shards": {
    "total": 1,
    "successful": 1,
    "skipped": 0,
    "failed": 0
  },
  "hits": {
    "total": {
      "value": 5,
      "relation": "eq"
    },
    "max_score": 1.0,
    "hits": [...]
  },
  "aggregations": {
    "my-agg-name": {                           
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": []
    }
  }
}

my-agg-name 聚合的结果。

更改聚合的范围

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使用 query 参数来限制聚合运行的文档

resp = client.search(
    index="my-index-000001",
    query={
        "range": {
            "@timestamp": {
                "gte": "now-1d/d",
                "lt": "now/d"
            }
        }
    },
    aggs={
        "my-agg-name": {
            "terms": {
                "field": "my-field"
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  body: {
    query: {
      range: {
        "@timestamp": {
          gte: 'now-1d/d',
          lt: 'now/d'
        }
      }
    },
    aggregations: {
      "my-agg-name": {
        terms: {
          field: 'my-field'
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  query: {
    range: {
      "@timestamp": {
        gte: "now-1d/d",
        lt: "now/d",
      },
    },
  },
  aggs: {
    "my-agg-name": {
      terms: {
        field: "my-field",
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search
{
  "query": {
    "range": {
      "@timestamp": {
        "gte": "now-1d/d",
        "lt": "now/d"
      }
    }
  },
  "aggs": {
    "my-agg-name": {
      "terms": {
        "field": "my-field"
      }
    }
  }
}
Copy as curlTry in Elastic 

仅返回聚合结果

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默认情况下，包含聚合的搜索会同时返回搜索命中结果和聚合结果。要仅返回聚合结果，请将 size 设置为 0

resp = client.search(
    index="my-index-000001",
    size=0,
    aggs={
        "my-agg-name": {
            "terms": {
                "field": "my-field"
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  body: {
    size: 0,
    aggregations: {
      "my-agg-name": {
        terms: {
          field: 'my-field'
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  size: 0,
  aggs: {
    "my-agg-name": {
      terms: {
        field: "my-field",
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search
{
  "size": 0,
  "aggs": {
    "my-agg-name": {
      "terms": {
        "field": "my-field"
      }
    }
  }
}
Copy as curlTry in Elastic 

运行多个聚合

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您可以在同一请求中指定多个聚合

resp = client.search(
    index="my-index-000001",
    aggs={
        "my-first-agg-name": {
            "terms": {
                "field": "my-field"
            }
        },
        "my-second-agg-name": {
            "avg": {
                "field": "my-other-field"
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  body: {
    aggregations: {
      "my-first-agg-name": {
        terms: {
          field: 'my-field'
        }
      },
      "my-second-agg-name": {
        avg: {
          field: 'my-other-field'
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  aggs: {
    "my-first-agg-name": {
      terms: {
        field: "my-field",
      },
    },
    "my-second-agg-name": {
      avg: {
        field: "my-other-field",
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search
{
  "aggs": {
    "my-first-agg-name": {
      "terms": {
        "field": "my-field"
      }
    },
    "my-second-agg-name": {
      "avg": {
        "field": "my-other-field"
      }
    }
  }
}
Copy as curlTry in Elastic 

运行子聚合

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桶聚合支持桶或指标子聚合。例如，带有 avg 子聚合的词项聚合计算每个文档桶的平均值。嵌套子聚合的级别或深度没有限制。

resp = client.search(
    index="my-index-000001",
    aggs={
        "my-agg-name": {
            "terms": {
                "field": "my-field"
            },
            "aggs": {
                "my-sub-agg-name": {
                    "avg": {
                        "field": "my-other-field"
                    }
                }
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  body: {
    aggregations: {
      "my-agg-name": {
        terms: {
          field: 'my-field'
        },
        aggregations: {
          "my-sub-agg-name": {
            avg: {
              field: 'my-other-field'
            }
          }
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  aggs: {
    "my-agg-name": {
      terms: {
        field: "my-field",
      },
      aggs: {
        "my-sub-agg-name": {
          avg: {
            field: "my-other-field",
          },
        },
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search
{
  "aggs": {
    "my-agg-name": {
      "terms": {
        "field": "my-field"
      },
      "aggs": {
        "my-sub-agg-name": {
          "avg": {
            "field": "my-other-field"
          }
        }
      }
    }
  }
}
Copy as curlTry in Elastic 

响应将子聚合结果嵌套在其父聚合下

{
  ...
  "aggregations": {
    "my-agg-name": {                           
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": [
        {
          "key": "foo",
          "doc_count": 5,
          "my-sub-agg-name": {                 
            "value": 75.0
          }
        }
      ]
    }
  }
}

父聚合 my-agg-name 的结果。

my-agg-name 的子聚合 my-sub-agg-name 的结果。

添加自定义元数据

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使用 meta 对象将自定义元数据与聚合关联

resp = client.search(
    index="my-index-000001",
    aggs={
        "my-agg-name": {
            "terms": {
                "field": "my-field"
            },
            "meta": {
                "my-metadata-field": "foo"
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  body: {
    aggregations: {
      "my-agg-name": {
        terms: {
          field: 'my-field'
        },
        meta: {
          "my-metadata-field": 'foo'
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  aggs: {
    "my-agg-name": {
      terms: {
        field: "my-field",
      },
      meta: {
        "my-metadata-field": "foo",
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search
{
  "aggs": {
    "my-agg-name": {
      "terms": {
        "field": "my-field"
      },
      "meta": {
        "my-metadata-field": "foo"
      }
    }
  }
}
Copy as curlTry in Elastic 

响应将 meta 对象原样返回

{
  ...
  "aggregations": {
    "my-agg-name": {
      "meta": {
        "my-metadata-field": "foo"
      },
      "doc_count_error_upper_bound": 0,
      "sum_other_doc_count": 0,
      "buckets": []
    }
  }
}

返回聚合类型

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默认情况下，聚合结果包含聚合的名称，但不包含其类型。要返回聚合类型，请使用 typed_keys 查询参数。

resp = client.search(
    index="my-index-000001",
    typed_keys=True,
    aggs={
        "my-agg-name": {
            "histogram": {
                "field": "my-field",
                "interval": 1000
            }
        }
    },
)
print(resp)
response = client.search(
  index: 'my-index-000001',
  typed_keys: true,
  body: {
    aggregations: {
      "my-agg-name": {
        histogram: {
          field: 'my-field',
          interval: 1000
        }
      }
    }
  }
)
puts response
const response = await client.search({
  index: "my-index-000001",
  typed_keys: "true",
  aggs: {
    "my-agg-name": {
      histogram: {
        field: "my-field",
        interval: 1000,
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search?typed_keys
{
  "aggs": {
    "my-agg-name": {
      "histogram": {
        "field": "my-field",
        "interval": 1000
      }
    }
  }
}
Copy as curlTry in Elastic 

响应会将聚合类型作为聚合名称的前缀返回。

某些聚合返回的聚合类型与请求中的类型不同。例如，词项、重要词项 和 百分位数 聚合会根据聚合字段的数据类型返回不同的聚合类型。

{
  ...
  "aggregations": {
    "histogram#my-agg-name": {                 
      "buckets": []
    }
  }
}

聚合类型 histogram，后跟一个 # 分隔符和聚合的名称 my-agg-name。

在聚合中使用脚本

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当字段与您需要的聚合不完全匹配时，您应该在 运行时字段 上进行聚合

resp = client.search(
    index="my-index-000001",
    size="0",
    runtime_mappings={
        "message.length": {
            "type": "long",
            "script": "emit(doc['message.keyword'].value.length())"
        }
    },
    aggs={
        "message_length": {
            "histogram": {
                "interval": 10,
                "field": "message.length"
            }
        }
    },
)
print(resp)
const response = await client.search({
  index: "my-index-000001",
  size: 0,
  runtime_mappings: {
    "message.length": {
      type: "long",
      script: "emit(doc['message.keyword'].value.length())",
    },
  },
  aggs: {
    message_length: {
      histogram: {
        interval: 10,
        field: "message.length",
      },
    },
  },
});
console.log(response);
GET /my-index-000001/_search?size=0
{
  "runtime_mappings": {
    "message.length": {
      "type": "long",
      "script": "emit(doc['message.keyword'].value.length())"
    }
  },
  "aggs": {
    "message_length": {
      "histogram": {
        "interval": 10,
        "field": "message.length"
      }
    }
  }
}
Copy as curlTry in Elastic 

脚本动态计算字段值，这会给聚合增加一些开销。除了计算所花费的时间外，某些聚合（如 terms 和 filters）无法将其某些优化与运行时字段一起使用。总的来说，使用运行时字段的性能成本因聚合而异。

聚合缓存

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为了获得更快的响应，Elasticsearch 会将频繁运行的聚合结果缓存在 分片请求缓存 中。要获取缓存的结果，请对每次搜索使用相同的 preference 字符串。如果不需要搜索命中结果，请 将 size 设置为 0，以避免填充缓存。

Elasticsearch 会将具有相同首选项字符串的搜索路由到相同的分片。如果分片的数据在搜索之间没有更改，则分片会返回缓存的聚合结果。

long 值的限制

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运行聚合时，Elasticsearch 使用 double 值来保存和表示数字数据。因此，对大于 253 的 long 数字进行的聚合是近似的。

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