Seed tablesample strategy
What does this MR do?
This changes the approximate counting strategy based on TABLESAMPLE to become stable across multiple invocations. Sampling is based on a RNG. We seed the RNG in order to get stable results (unless the table changed between invocations).
For details, see TABLESAMPLE part of https://www.postgresql.org/docs/9.6/sql-select.html.
What are the relevant issue numbers?
Edited by Andreas Brandl