On 2020-Jun-08, Tomas Vondra wrote: > Not sure if it's sufficient, though, because switching to logical may > require bumping up number of slots, walsenders, etc. At which point you > actually need a restart. Not to mention that extensions using logical > decoding (like pglogical) need to allocate shared memory etc. But for > the built-in logical replication that is not an issue, ofc.
I think it's reasonable to push our default limits for slots, walsenders, max_bgworkers etc a lot higher than current value (say 10 -> 100). An unused slot wastes essentially no resources; an unused walsender is just one PGPROC entry. If we did that, and also allowed wal_level to be changed on the fly, we wouldn't need to restart in order to enable logical replication, so there would be little or no pressure to change the wal_level default. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
