PostgreSQL 10 High Performance - Third Edition

Enabling autovacuum on older versions

If you have autovacuum available but it's not turned on by default, which will be the case with PostgreSQL 8.1 and 8.2, there are a few related parameters that must also be enabled for it to work, as covered at http://www.postgresql.org/docs/8.1/interactive/maintenance.html or http://www.postgresql.org/docs/8.2/interactive/routine-vacuuming.html.

The normal trio to enable in the file in these versions are:

stats_start_collector=true 
stats_row_level=true 
autovacuum=on 

Note that as warned in the documentation, it's also wise to consider adjusting superuser_reserved_connections to allow for the autovacuum processes in these earlier versions.

The autovacuum you'll get in 8.1 and 8.2 is not going to be as ...