使用Elasticsearch计算文档数

本文介绍了使用Elasticsearch计算文档数的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 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

为某些文档编制索引

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.