Hi,Mongo has a global write/read lock - Reads can happen concurrently,
but only one write executes at a time, and some write operations will
intelligently yield.However, mongo updates are very fast especially
when using in-place modifiers. Your best bet in getting an idea of how
the two compare for your application is probably to writing a simple
test/benchmark to simulate the type of data + loads you are expecting
- you can use mongostat to check lock %.
For additional performance, you could also separate read and write
queries by setting up replication, and sending your read queries to
the slave, and sending all writes to the master. Also note that
collection-level will be coming soon (
https://jira.mongodb.org/browse/
SERVER-1240) which will further reduce chances of lock contention.
Hope this helps,-Mike