Rework stats reset section
Use the recipe from https://gitlab.com/postgres-ai/postgresql-consulting/postgres-howtos/-/blob/main/0050_pre_and_post_steps_for_benchmark_iterations.md#pre-step-reset-statistics to reset stats. It gives a few benefits:
- conditional reset for extensions (e.g., if
pg_stat_kcache
is not installed, no reset attempt for it will happen) - more types of core stats is reset, depending on PG version -- e.g.,
pg_stat_io
for PG16+
Additionally:
- when collecting artifacts after an iteration, the logic is adjusted not to fail if pg_stat_kcache or pg_wait_sampling are not installed
- do not prune the output of the reset attempt – all the reset messages are essential for further analysis of the experiment
Edited by Nikolay Samokhvalov