I'm agreeing with your comment, not arguing with it.
The problems we had moving from mmapv1 to rocksdb were almost entirely based on the rewrite of the query planner in 2.6, not the storage engine itself.
The WT storage engine is far less mature than RocksDB. Only a very tiny amount of code in the Mongo+Rocks integration is actually new code, it's just the thin layer of glue between mongo and the storage engine API.
It was a tricky migration because we made the decision to do it early while so much code was still new in mongo for that version. We wanted to help give feedback on the storage engine API because we had pushed so hard for that feature, and because we were pushing the boundaries of what the mmap engine could ever reasonably be expected to do.
(Side note: OMG, anyone who measures their request rate in anything other than per-second is putting up a giant red flag that they don't know what they're doing.)
Right, I knew there was a misunderstanding initially over what company I was referring to (CleverTap, not 10gen/MongoDB) and we were mostly on the same page :)
RocksDB is great, WT is getting to be great, both are getting better and have solid teams working on them. LSMs have great use cases, btrees too. 600 QPS you do not blog about.
The problems we had moving from mmapv1 to rocksdb were almost entirely based on the rewrite of the query planner in 2.6, not the storage engine itself.
The WT storage engine is far less mature than RocksDB. Only a very tiny amount of code in the Mongo+Rocks integration is actually new code, it's just the thin layer of glue between mongo and the storage engine API.
It was a tricky migration because we made the decision to do it early while so much code was still new in mongo for that version. We wanted to help give feedback on the storage engine API because we had pushed so hard for that feature, and because we were pushing the boundaries of what the mmap engine could ever reasonably be expected to do.
(Side note: OMG, anyone who measures their request rate in anything other than per-second is putting up a giant red flag that they don't know what they're doing.)