使用Elasticsearch计算文档数 [英] Counting number of documents using Elasticsearch

问题描述

如果要计算索引（Elasticsearch的索引）中的文档数，则（至少？）有两种可能性：

If one wants to count the number of documents in an index (of Elasticsearch) then there are (at least?) two possibilities:

• 直接个计数

• Direct count

POST my_index / _count

POST my_index/_count

应返回 my_index 中的文档数。

使用搜索

Using search

这里可以使用计数作为 search_type 或其他某种类型。在这两种情况下，都可以从字段 ['hits'] ['total']

Here one can use the count as the search_type or some other type. In either of the cases the total count can be extracted from the field ['hits']['total']

我的问题是：

• 不同方法之间有什么区别？我应该选择哪一个
  ？

• what is the difference between the different approaches? Which one should I prefer?

我提出这个问题是因为根据所选择的方法，我遇到了不同的结果
。我现在正在调试
的问题，然后弹出该问题。

I raise this question because I'm experiencing different results depending on the chosen method. I'm now in the process of debugging the issue, and this question popped up.

推荐答案

可能 _count 有点快，因为它不必执行带有排名和结果获取的完整查询，并且只需返回大小即可。

Probably _count is a bit faster since it doesn't have to execute a full query with ranking and result fetching and can simply return the size.

了解更多有关如何获得不同结果的知识会很有趣。为此，我需要更多信息，例如您要发送的确切查询以及索引上是否有任何索引。

It would be interesting to know a bit more about how you manage to get different results though. For that I need more information like what exact queries you are sending and if any indexing is going on on the index.

但是假设您执行以下操作

But suppose that you do the following

1. 为某些文档编制索引


2. 刷新索引

_search 和 _count （全部匹配）将返回相同的总数。如果没有，那将是很奇怪。

_search and _count (with a match all query) should return the same total. If not, that'd be very weird.

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