April 2010
6 posts
MongoDB Q1 Download Numbers
The MongoDB team is very excited about how the developer community is building around MongoDB, and we wanted to share some numbers. These are download numbers for the core server for January through March.  It is exactly the number of downloads of the core database from downloads.mongodb.org minus all bots (all known plus anything with bot in the user-agent) and all other crawlers we...
Apr 26th
3 notes
5 tags
On Distributed Consistency - Part 6 - Consistency...
See also: Part 1 - Introduction and CAP Part 2 - Eventual Consistency Part 3 - Network Partitions Part 4 - Multi Data Center Part 5 - Multi Writer Eventual Consistency The following diagram (click for large version) shows the various consistency models that have been discussed in this blog post series.  Stronger consistency modes generally meet the requirements of weaker modes, and are thus...
Apr 15th
3 tags
On Distributed Consistency - Part 5 - Many Writer...
See also: Part 1 - Introduction and CAP Part 2 - Eventual Consistency Part 3 - Network Partitions Part 4 - Multi Data Center Part 6 - Consistency Chart In part 2 we primarily discussed “single writer” eventual consistency.  Here we will discuss many-writer, and define that term more precisely. By many-writer, we mean a system where different data servers can receive writes...
Apr 14th
3 notes
2 tags
On Distributed Consistency - Part 4 - Multi Data...
See also: Part 1 - Introduction and CAP Part 2 - Eventual Consistency Part 3 - Network Partitions Part 5 - Multi Writer Eventual Consistency Part 6 - Consistency Chart Eventual consistency makes multi-data center data storage easier.  There are reasons eventual consistency is helpful for multi-data center that are unrelated to availability and CAP.  And as mentioned in Part 3, some common...
Apr 12th
1 note
On Distributed Consistency - Part 3 - Network...
See also: Part 1 - Introduction and CAP Part 2 - Eventual Consistency Part 4 - Multi Data Center Part 5 - Multi Writer Eventual Consistency Part 6 - Consistency Chart It’s fascinating that the formal theorem statement for CAP, in the first proof (that I know of), doesn’t use the word partition! Theorem 1 It is impossible in the asynchronous network model to implement a...
Apr 8th
On Distributed Consistency - Part 2 - Some...
See Also Part 1 - Introduction and CAP Part 3 - Network Partitions Part 4 - Multi Data Center Part 5 - Multi Writer Eventual Consistency Part 6 - Consistency Chart In Part 1 we discussed C-class and A-class behaviors.  For A-class, we need to weaken consistency constraints.  This does not mean the system need be completely inconsistent, but it does mean we will need to relax the consistency...
Apr 5th
4 notes