如何在Elasticsearch的现有映射中添加新字段时添加默认值 [英] How to add default values while adding a new field in existing mapping in elasticsearch

问题描述

这是我现有的弹性搜索子文档之一的映射

This is my existing mapping in elastic search for one of the child document

sessions" : {
    "_routing" : {
    "required" : true
    },
    "properties" : {
       "operatingSystem" : {
       "index" : "not_analyzed",
       "type" : "string"
    },
    "eventDate" : {
       "format" : "dateOptionalTime",
       "type" : "date"
    },
    "durations" : {
       "type" : "integer"
    },
    "manufacturer" : {
       "index" : "not_analyzed",
       "type" : "string"
    },
    "deviceModel" : {
       "index" : "not_analyzed",
       "type" : "string"
    },
    "applicationId" : {
       "type" : "integer"
    },
    "deviceId" : {
       "type" : "string"
    }
    },
    "_parent" : {
       "type" : "userinfo"
    }
}

在上面的映射持续时间字段是一个整数数组。我需要添加一个名为 durationCount的新字段来更新现有的映射，该字段的默认值应为durations数组的大小。

in above mapping "durations" field is an integer array. I need to update the existing mapping by adding a new field called "durationCount" whose default value should be the size of durations array.

PUT sessions/_mapping
{
    "properties" : {
    "sessionCount" : {
      "type" :    "integer"
    }
  }
}

使用上述映射，我可以更新现有映射，但无法找出在更新映射时如何分配值（每个会话文档的值会有所不同，就像应该为durations array size一样）。有什么想法吗？

using above mapping I am able to update the existing mapping but I am not able to figure out how to assign a value ( which would vary for each session document like it should be durations array size ) while updating the mapping. any ideas ?

推荐答案

这里有2条建议-

1. 您可以使用缺少的过滤器在查询中调整默认值，而不是添加默认值。假设您要基于匹配查询进行搜索-而不是仅使用匹配查询，请使用布尔查询以及具有匹配项和缺少过滤器。在经过过滤的查询中。这样，那些没有该字段的文档也会被考虑。


2. 如果您绝对需要现有文档在该字段中的值，则需要重新索引整个文档集。或者，使用开箱即用的插件通过查询进行更新-

1. Instead of adding default value , you can adjust it in the query using missing filter. Lets say , you want to search based on a match query - Instead of just match query , use a bool query with should clause having the match and missing filter. inside filtered query. This way , those documents which did not have the field is also accounted.
2. If you absolutely need the value in that field for existing documents , you need to reindex the whole set of documents. Or , use the out of box plugin , update by query -

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