In MongoDB mapreduce, how can I flatten the values object?

Question

I\'m trying to use MongoDB to analyse Apache log files. I\'ve created a receipts collection from the Apache access logs. Here\'s an abridged summary of what my

Answer 1

All the proposed solutions are far from optimal. The fastest you can do so far is something like:

var flattenMRCollection=function(dbName,collectionName) {
    var collection=db.getSiblingDB(dbName)[collectionName];

    var i=0;
    var bulk=collection.initializeUnorderedBulkOp();
    collection.find({ value: { $exists: true } }).addOption(16).forEach(function(result) {
        print((++i));
        //collection.update({_id: result._id},result.value);

        bulk.find({_id: result._id}).replaceOne(result.value);

        if(i%1000==0)
        {
            print("Executing bulk...");
            bulk.execute();
            bulk=collection.initializeUnorderedBulkOp();
        }
    });
    bulk.execute();
};

Then call it: flattenMRCollection("MyDB","MyMRCollection")

This is WAY faster than doing sequential updates.