Yes, to both. The transaction log is append only, so there are more optimal methods (including lock-free approaches to make it efficient. Also, the duration of

Yes, to both. The transaction log is append only, so there are more optimal methods (including lock-free approaches to make it efficient. Also, the duration of the lock is limited to the append operation, and not determined by application (when the atomically block ends). And yes, STM and high contention don't mix. It works well for occasional writes and predominant reads. Tim Sweeney's presentation on this topic is hugely informative. https://www.st.cs.uni-saarland.de//edu/seminare/2005/advanced-fp/docs/sweeny.pdf https://www.st.cs.uni-saarland.de//edu/seminare/2005/advance...