多个键范围作为CouchDB视图的参数 [英] Multiple key ranges as parameters to a CouchDB view

问题描述

潜在的问题-假设我的文档包含类别 和时间戳。如果我想要 foo 类别中所有时间戳都在最近两个小时内的文档，则很简单：

 函数（doc）{
发出（[doc.category，doc.timestamp]，null）; 
} 
  

，然后查询

 获取服务器：5894 /.../ myview？startKey = [foo，| now-2 hours |]& endkey = [foo，| now |] 
  

问题是当我想要类别 foo 或 bar ，在最近两个小时内。如果我不在乎时间，可以直接通过钥匙来拉动钥匙。不幸的是，我没有范围选项。

  POST服务器：5894 /.../ myview 
 keys = [[foo，0 hours]，[foo ，2 hours]，[bar，0 hours]，[bar，2 hours]] 
  

它有效，但是如果我想返回大量时间（与块大小有关），将会变得混乱。

是否可以发送多个startKey / endKey对类似于键的视图：[]可以为键发布的数组？

解决方案

有一个CouchDB问题请求让你做到这一点。我在票证上附加了一个简单的，无保证的补丁0.10.1，可能对您有用。它对我有用，让我做类似的事情：

  {
 keys：[
 { 
 startkey：[ 0240286524， 2010， 03， 01]，
 endkey：[ 0240286524， 2010， 03， 07 ，{}] 
}，
 {
 startkey：[ 0442257276， 2010， 03， 01]，
 endkey：[  0442257276， 2010， 03， 07，{}] 
} 
] 
} 
  

在POST正文中，这使我可以在多个日期范围内跨多个跟踪ID获取所有数据。我用 group = true& group_level = 1 打电话，将结果按跟踪ID分组。较深的组级别将允许我通过跟踪id | year，跟踪id | year | month等进行分组。

对于我来说，多个连接对我来说是无法扩展的开销希望同时达到2000：）（不，不能选择新视图-我们已经有400GB的数据和一个视图！）

问题和补丁在 https://issues.apache.org/jira/browse/COUCHDB-523。

The underlying problem - let's say my documents have "categories" and timestamps. If I want all documents in the "foo" category that have a timestamp that's within the last two hours, it's simple:

function (doc) {
  emit([doc.category, doc.timestamp], null);
}

and then query as

GET server:5894/.../myview?startKey=[foo, |now - 2 hours|]&endkey=[foo, |now|]

the problem comes when I want something in categories foo or bar, within the last two hours. If I didn't care about time, I could just pull directly by key through the keys collection. unfortunately, I have no such option with ranges.

What I ended up doing in the meantime is rounding the timestamp to two-hour blocks, and then multiplexing the query out:

POST server:5894/.../myview
keys=[[foo, 0 hours], [foo, 2 hours], [bar, 0 hours], [bar, 2 hours]]

It works, but will get messy if I want to go back a large amount of time (in relationship to the blocksize).

Is there a way to send multiple startKey/endKey pairs to a view, akin to the keys: [] array that can be posted for keys?

解决方案

There is a CouchDB issue request to let you do just that. I've attached a simple, no guarantees patch to 0.10.1 to that ticket which may work for you. It works for me and lets me do things like:

{
    "keys": [
        {
            "startkey": ["0240286524","2010","03","01"],
            "endkey": ["0240286524","2010","03","07",{}]
        },
        {
            "startkey": ["0442257276","2010","03","01"],
            "endkey": ["0442257276","2010","03","07",{}]
        }
    ]
}

in the POST body, which lets me get all the data across multiple tracking ids, for a range of dates. I call with group=true&group_level=1 to have the results grouped by tracking id. Deeper group levels would allow me to group by tracking id|year, tracking id|year|month etc.

Multiple connections were an unscalable overhead for me as I'd be looking to make 2000 concurrently :) (No, a new view is not an option - we're already at 400GB for data plus one view!)

The issue and patch is at https://issues.apache.org/jira/browse/COUCHDB-523 .

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