PostgreSQL 11 lets you create a data directory with group read access (0750) instead of owner-only (0700), enabling unprivileged backup processes to copy files…
A read-only preset, like block_size — SHOW data_checksums tells you whether the cluster has page checksums, and that’s the only interaction the GUC offers. But
The planner assumes cursors fetch only 10% of results by default. If you're actually reading them all, that fast-start bias could be killing your performance.