CODEWITHSUNDEEP
node.jsmongodb
onurbaysan
onurbaysan

Reputation: 1258

Get the max element in mongodb collection throws exception

I have a trouble with the code below. I try to get max(seq) in 'links' collection. After run the code below, I get "FATAL ERROR: JS Allocation failed - process out of memory" error. How can I overcome that problem? Thank you for your replies.

db.collection('links', function(err, collection) {  
        var options = { "limit": 1, "sort": [['seq','desc']]};

        collection.find({}, options , function(err, docs) {            
            console.log("Returned #" + docs.seq + " documents");
        }); 
});

Note: Memory usage of node has incredibly increased after running, by the way.

Upvotes: 2

Views: 1442

Answers (1)

JohnnyHK
JohnnyHK

Reputation: 312025

Add an index on seq to your collection so that Mongo doesn't have to load the whole collection into memory to sort it.

Also, use findOne instead of find as the docs parameter in your current code is actually a cursor object, not the doc with the max seq. As in:

var options = { "sort": [['seq','desc']] };
collection.findOne({}, options , function(err, doc) {
    console.log("Returned #" + doc.seq + " documents");
});

Upvotes: 1

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