如何计算百分位数? [英] How to calculate the percentile?

问题描述

我将以下访问日志存储在mongodb实例中:

I have access logs such as below stored in a mongodb instance:

Time                           Service                      Latency
[27/08/2013:11:19:22 +0000]    "POST Service A HTTP/1.1"    403
[27/08/2013:11:19:24 +0000]    "POST Service B HTTP/1.1"    1022 
[27/08/2013:11:22:10 +0000]    "POST Service A HTTP/1.1"    455 

Oracle中是否有像PERCENTILE_DISC这样的分析功能来计算百分位数?

Is there an analytics function like PERCENTILE_DISC in Oracle to calculate the percentile?

我想计算一段时间内的延迟百分比.

I would like to calculate latency percentiles over a period of time.

推荐答案

似乎还没有原生方法来计算百分位数，但是通过组合一些聚合运算符，您可以获得相同的结果.

There still appears to be no native way to calculate percentiles but by combining a few aggregate operators you can get the same result.

db.items.aggregate([
        {'$group': {
            '_id': {
                'league': '$league',
                'base': '$base',
                'type': '$type'
            },
            'value': {'$push': '$chaosequiv'}
        }},
        {'$unwind': '$value'},
        {'$sort': {'value': 1}},
        {'$group': {'_id': '$_id', 'value': {'$push': '$value'}}},
        {'$project': {
            '_id': 1,
            'value': {'$arrayElemAt': ['$value', {'$floor': {'$multiply': [0.25, {'$size': '$value'}]}}]}
        }}
    ], allowDiskUse=True)

请注意，我用pymongo编写了我的原始代码，该问题需要将第一组中的3个字段分组，因此这可能比单个字段所需的更为复杂.我会针对此问题编写解决方案，但我认为没有足够的具体信息.

Note I wrote my original code in pymongo for a problem that needed to group on 3 fields in the first group so this may be more complex than necessary for a single field. I would write a solution specific to this question but I don't think there is enough specific information.

这篇关于如何计算百分位数?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！