CODEWITHSUNDEEP
databasecouchdbmax
fanjavaid
fanjavaid

Reputation: 1738

Getting max value in CouchDB

i am trying to use CouchDB as my Database. I have problem when i want to get max value from 50000 records. What the best solution to find max value?

I use this reduce function :

function (key, values, rereduce) {
    var largest = Math.max.apply(Math, key);
    return largest;
}

And this is my map function :

function(doc) {
    if(doc.TYPE=="customer"){
       emit(doc._id.substring(0,8), doc._id);
    }
}

Thank you

Upvotes: 0

Views: 2589

Answers (1)

Dominic Barnes
Dominic Barnes

Reputation: 28429

When writing reduce functions, you should not forget to account for the rereduce parameter. However, you don't really even need it for 2 reasons:

1) you can just use descending=true when you query the view and get the largest item. (so you wouldn't need a reduce step at all)

2) you can use the builtin reduce function _stats and get the max value w/o writing your own reduce function.

The advantage to just using the map function w/o the reduce function is that you can not only get the largest value, but also the document that contains that value.

Upvotes: 1

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