We generally believe that the most common workload is for reads to exponentially prefer most recently written data. However as stress currently behaves we have two id generation modes: sequential and random (although random can be distributed). I propose introducing a new mode which is somewhat like sequential, except we essentially 'look back' from the current id by some amount defined by a distribution. I may possibly make the position only increment as it's first written to also, so that this mode can be run from a clean slate with a mixed workload. This should allow is to generate workloads that are more representative.
At the same time, I will introduce a timestamp value generator for primary key columns that is strictly ascending, i.e. has some random component but is based off of the actual system time (or some shared monotonically increasing state) so that we can again generate a more realistic workload. This may be challenging to tie in with the new procedurally generated partitions, but I'm sure it can be done without too much difficulty.