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MongoDB driver tips & tricks: Mongoose

Many of the support requests we get at MongoLab are questions about how to properly configure and use particular MongoDB drivers and client libraries.

This blog post is the 2nd of a series where we are covering the popular MongoDB drivers in depth (we covered Mongoid last time). The driver we’re covering today is Mongoose, which is maintained by Aaron Heckmann (@aaronheckmann) and officially supported by MongoDB, Inc. Continue Reading →

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MongoLab now manages over 100,000 databases! (102,280 to be exact)

We’re proud to announce that MongoLab is now powering over 100,000 cloud MongoDB databases in 23 datacenters worldwide! Continue Reading →

Finding duplicate keys with MongoDB’s aggregation framework

Quite frequently our users want to create a unique index on a data set but encounter some form of the following error because of duplicate key value(s):

E11000 duplicate key error index: db.collection.$field_1_field2_1  dup key: { : 1.0 : 1.0 }

While MongoDB supports an option to drop duplicates, dropDups, during index builds, this option forces the creation of a unique index by way of deleting data. If you use the dropDups option, MongoDB will create an index on the first occurrence of a value for a given key and then  delete all subsequent values. While this behavior may be acceptable in some cases, it’s important to be cautious whenever you are deleting data. Continue Reading →

MongoDB driver tips & tricks: Mongoid 3

Many of the support requests we get at MongoLab are questions about how to properly configure and use particular MongoDB drivers.

This blog post is the first of a series where we plan to cover each of the major MongoDB drivers in depth. The driver we’ll be covering today is Mongoid, developed by Durran Jordan (@modetojoy). Continue Reading →

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Future of MongoDB: Fireside chat with MongoDB CTO Eliot Horowitz

Last night I attended a Meetup at MongoDB Inc.’s new Palo Alto office to hear MongoDB’s CTO, Eliot Horowitz, speak about the product roadmap. With a new production release right around the corner and MongoDB World in the not-so-distant future, the buzz and excitement around all things MongoDB is high. For those who were not able to attend, we’re going to recap all the major points Eliot made.

Continue Reading →

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Finding and terminating long-running operations in MongoDB

When your MongoDB becomes unresponsive, it’s imperative that you can quickly identify the cause.

Although there can be many reasons for unresponsiveness, we sometimes find that particularly long-running and/or blocking operations (either initiated by a human or an application) are the culprit. Some examples of common operations that can bog down the database are:

  • operations on unindexed fields

  • index builds

  • expensive map-reduce jobs

One way to quickly see if one or more operations are particularly long-running is to use db.currentOp().

Continue Reading →

Managing disk space in MongoDB

In our previous post on MongoDB storage structure and dbStats metrics, we covered how MongoDB stores data and the differences between the dataSize, storageSize and fileSize metrics. We can now apply this knowledge to evaluate strategies for re-using MongoDB disk space.

When documents or collections are deleted, empty record blocks within data files arise. MongoDB attempts to reuse this space when possible, but it will never return this space to the file system. This behavior explains why fileSize never decreases despite deletes on a database.

If your app frequently deletes or if your fileSize is significantly larger than the size of your data plus indexes, you can use one of the methods below reclaim free space. Continue Reading →

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How big is your MongoDB?

As your MongoDB grows in size, information from the db.stats() diagnostic command (or the database “Stats” tab in our management portal) becomes increasingly helpful for evaluating hardware requirements.

We frequently get questions about the dataSize, storageSize and fileSize metrics, so we want to help developers better understand how MongoDB storage works and what these particular metrics mean.

Continue Reading →

{ "comments": 4 }