Cloudant:此排序不存在索引，请尝试按排序字段建立索引 [英] Cloudant: No index exists for this sort, try indexing by the sort fields

问题描述

我的问题持续了几天，我无法解决.

I have a problem that persists for a few days and I cannot solve it.

我的数据库中有一个简单的文档，如下所示:

I have a simple document in my database which looks like this:

{
  "_id": "asd123",
  "_rev": "revidasd123",
  "type": "CUSTOM_TYPE",
  "position": 8,
  "title": "Short custom title"
}

当我尝试按位置进行排序时，即使我为此字段创建了索引，也总是会遇到相同的错误:

When I try to make a sort by position, even if I have created an index for this field, I always get the same error:

错误:no_usable_index.原因:这种排序不存在索引，请尝试按排序字段建立索引.

这里是索引:

{
 "type": "json",
 "def": {
  "fields": [
   {
    "position": "asc"
   }
  ]
 }
}

这是导致此错误的我的查询:

And here is my query which cause this error:

{
  "selector": {
    "type": "CUSTOM_TYPE",
    "_id":{
      "$gt": null
    }
  },
  "fields": [
    "_id",
    "type",
    "position"
  ],
  "sort": [
    {
      "_id": "asc"
    },
    {
      "position": "asc"
    }
  ]
}

结果:该排序没有索引，请尝试按排序字段建立索引.

请帮助！在此先感谢

推荐答案

如果要按位置排序，请尝试以下查询:

If you want to sort by position then try this query:

{
  "selector": {
    "type": "CUSTOM_TYPE",
    "position": {"$gte": 0}
  },
  "fields": [
    "_id",
    "type",
    "position"
  ],
  "sort": [
    {
      "position": "asc"
    }
  ]
}

position字段必须是选择器的一部分.我将其设置为匹配> = 0的任何位置，因此除非它为null，否则应该匹配所有位置.

The position field needs to be part of the selector. I set it to match any position that is >= 0, so it should match all unless it's null.

此外，您还按_id和position进行排序.这将使position排序变得毫无意义.我从排序中删除了_id字段.

Also, you were sorting by _id and then position. This would render the position sort meaningless. I removed the _id field from the sort.

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