July 2009
5 posts
1 tag
Work full time on MongoDB : 10gen is hiring C++...
10gen, which provides commercial support for MongoDB, is hiring C++ developers to work on the project. If you are interested, we think the best way to start talking would be to pick something from Jira and just fix it as a micro project!  Then get in touch on IRC or by email (dwight at 10gen dt com). 10gen is located in New York City. Thanks, Dwight M
Jul 17th
4 tags
What is the Right Data Model?
There is certainly plenty of activity in the nonrelational (“NOSQL”) db space right now.  We know for these projects the data model is not relational.  But what is the data model?  What is the right model? There are many possibilities, the most popular of which are: Key/Value. Pure key/value stores are blobs stored by key. Tabular. Some projects use a Google BigTable-like data model...
Jul 16th
1 note
32-bit limitations
32-bit MongoDB processes are limited to about 2.5 gb of data.  This has come as a surprise to a lot of people who are used to not having to worry about that.  The reason for this is that the MongoDB storage engine uses memory-mapped files for performance. By not supporting more than 2gb on 32-bit, we’ve been able to keep our code much simpler and cleaner.  This greatly reduces the number of...
Jul 8th
12 notes
1 tag
Reaching into Objects
MongoDB is a JSON-style store.  Just like JSON, we can nest objects within other objects, and also arrays of data within objects. This then suggests the question or issue: how does one perform a query on nested objects?  Index keys in nested objects?  This is very important of course.  The following doc page explains the method. http://www.mongodb.org/display/DOCS/Dot+Notation
Jul 4th
1 tag
Databases and Predictability of Performance
A subject which perhaps doesn’t get enough attention is whether the performance of a database is predictable. What we are asking is: are there ever any surprises or gotchas in the time it takes for a db operation to execute?  For traditional database management systems, the answer is yes. For example, statistical query optimizers can be unpredictable: if the statistics for a table change in...
Jul 1st
2 notes