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POCouchDB - filter latest log per logged instance from a list
 

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    <p>i could use some help filtering distinct values from a couchdb view. I have a database that stores logs with information about computers. Periodically new logs for a computer are written to the db.</p> <p>A bit simplified i store entries like these:</p> <pre><code>{ "name": "NAS", "os": "Linux", "timestamp": "2011-03-03T16:26:39Z", } { "name": "Server1", "os": "Windows", "timestamp": "2011-02-03T19:31:31Z", } { "name": "NAS", "os": "Linux", "timestamp": "2011-02-03T18:21:29Z", } </code></pre> <p>So far i am struggling to filter this list by distinct entries. What i'd like to receive is the latest logfile for each device.</p> <p>I have a view like this:</p> <pre><code>function(doc) { emit([doc.timestamp,doc.name], doc); } </code></pre> <p>Im querying this view with python (couchdbkit) and the best solution i came up with so far looks like this:</p> <pre><code>def get_latest_logs(cls): unique_names = [] unique = [] for log in cls.view("logs/timestamp", descending=True): if log.name not in unique_names: unique_names.append(log.name) unique.append(log) return unique </code></pre> <p>Okay ... this works. But i have the strong feeling, that this is not the best solution as python needs to iterate the whole list of logfiles (which could become quite long).</p> <p>I guess i need a reduce function but i couldn't really find any examples or explanations that i could adapt to my problem.</p> <p>So, what i am looking for is a (pure couchdb) view, that only spits out the latest log for a given device.</p> <p>Thanks, Andreas</p>
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