hadoop - Elasticsearch:数周的聚合 min_doc_count 不起作用

Question

我对 interval=week 和 min_doc_count=0

进行了以下聚合

{
  "aggs": {
    "scores_by_date": {
      "date_histogram": {
      "field": "date",
      "format": "yyyy-MM-dd",
      "interval": "week",
      "min_doc_count": 0
    }
  }
}

和日期过滤器从 Jan-01-2015 到 Feb-23-2015

{
  "range": {
    "document.date": {
      "from": "2015-01-01",
      "to": "2015-02-23"
    }
  }
}

我预计 Elasticsearch 会填满七个星期，即使是空的并返回桶，但最终只有一个项目在里面

{
  "aggregations": {
    "scores_by_date": {
      "buckets": [
        {
          "key_as_string": "2015-01-05",
          "key": 1420416000000,
          "doc_count": 5
        }
      ]
    }
  }
}

Elasticsearch 版本:1.4.0

我的聚合有什么问题，或者我如何使用 Elasticsearch 来填补缺失的周数？

Answer 1

您可以尝试指定扩展边界(在 histogram aggregations 的官方文档页面上有讨论此功能的文档)。这些文档中最相关的部分是:

With extended_bounds setting, you now can "force" the histogram aggregation to start building buckets on a specific min values and also keep on building buckets up to a max value (even if there are no documents anymore). Using extended_bounds only makes sense when min_doc_count is 0 (the empty buckets will never be returned if min_doc_count is greater than 0).

因此您的聚合可能必须看起来像这样以强制 ES 返回该范围内的空桶:

{
  "aggs": {
    "scores_by_date": {
      "date_histogram": {
      "field": "date",
      "format": "yyyy-MM-dd",
      "interval": "week",
      "min_doc_count": 0,
      "extended_bounds" : {
        "min" : "2015-01-01",
        "max" : "2015-02-23"
      }
    }
  }
}