Topics

mongodb

Workaround for the slow pagination using skip in MongoDB

Recently I came across a big MongoDB database which needed pagination. But it was surprising how getting to page number 2000 ended up in a timeout. A quick research led me to MongoDB documentation:

The cursor.skip() method is often expensive because it requires the server to walk from the beginning of the collection or index to get the offset or skip position before beginning to return results. As the offset (e.g. pageNumber above) increases, cursor.skip() will become slower and more CPU intensive. With larger collections, cursor.skip() may become IO bound.

So “skip” clearly won’t work for a big set which led to the sort and gt solution.

Sorting and $gt:

Simply sorting by a created_at field then continuing from the last known created_at date by finding the next set would solve the problem.

ids = db.c.find({}, {_id:1}).map(function(item){ return item._id; });
docs = db.c.find( { _id: { $in: ids.slice(2000,2050) } } );

By continuing to use the site, you agree to the use of cookies. more information

The cookie settings on this website are set to "allow cookies" to give you the best browsing experience possible. If you continue to use this website without changing your cookie settings or you click "Accept" below then you are consenting to this.

Close