[VWWHFSfQ]

Right but postgres isn't going to help with this if the application developer isn't doing safe and proper transaction management in the first place. What you described is a bug in the application logic for when and how to update the cache.

[singron]

It's super hard to get this right. E.g. if you only update the cache after the transaction commits, you might commit without updating the cache, or if 2 writers interleave, the first one to commit might make the final update to the cache with a stale value.