The developers at Meteor have just released Meteor 1.0.4. This release is great news for any Compose and Meteor users who've been keeping their MongoDB database at version 2.4 or requesting downgrades, because this new Meteor officially supports MongoDB 2.6 and 3.0. For those who don't know Meteor, it's an application framework for the web which makes creating synchronised web applications remarkably easy and as its database backend it uses MongoDB and can use MongoDB's oplog for speed and scale.
For us in testing, Meteor's oplog handling has worked well, but we understood there were corner cases where things could go awry. For people with those corner cases, the common option was to drop back to 2.4 which we could help with. With Meteor 1.0.4, that issue has now gone away as the code that was "carefully wirtten to be bug-compatible with 2.4" has been taken out and replaced with new code that matches 2.6 and 3.0 MongoDB. Meteor now ships its development environment with MongoDB 2.6 and that, in turn, means you can use Compose MongoDB 2.6 knowing it's a fully supported database.
There are other enhancements in Meteor 1.0.4's database handling too. An up to 10x speedup in common queries with the oplog driver and an automatic fallback to poll-and-diff if the Meteor server falls behind processing the oplog should help all applications remain responsive. There's also access to the underlying database and collection through new
rawCollection methods for when you really can't avoid getting directly to grips with the MongoDB beneath the framework.
The Thrill of Threedom
You may notice that the Meteor developers aren't moving their default MongoDB to 3.0 yet and we applaud their cautious approach. It hasn't been out in the field long enough for anyone to make it default and upgrading to it should only be done outside business critical operations. We have found some people are rushing to update production use of MongoDB to 3.0 without testing and we can only ask them to please, test first, either locally or with a separate MongoDB deployment on Compose. If you're thinking of upgrading to 3.0 and are unsure what is best practice for testing that before you do it, drop a line to email@example.com and we'll point you in the right direction.
The League of Versions
To keep track of all current available versions, we have our League of Versions table. This is updated as we roll out new versions or change defaults. Generally, we support upgrades only - contact firstname.lastname@example.org if you need advice on any other version change or for assistance upgrading.
|Database||Supported Versions||Default Version|
|Compose MongoDB Sandboxes run MongoDB 2.4.|
|MongoDB||2.6.6, 2.6.8, 3.0.0||2.6.8|
|Redis||2.8.17, 2.8.18, 2.8.19||2.8.19|
Note: This article is part of the Compose Support Desk series