We increased "vacuum_cost_limit" globally and decreased "autovacuum_vacuum_scale_factor" and "autovacuum_analyze_scale_factor" for large tables. Most of them by a factor 4~5x.

The docs explain the different settings: https://www.postgresql.org/docs/9.6/static/runtime-config-au...

When tweaking performance settings, always benchmark, especially with your specific load characteristics.

I believe parent is referring essentially to the auto vacuum scale factor parameter (https://www.postgresql.org/docs/9.6/static/runtime-config-au...)

For a big table with frequent writes, the default is too much (20% dead tuples).