Re: Getting rid of wal_level=archive and default to hot_standby + wal_senders

Andres Freund <andres(at)2ndquadrant(dot)com> writes:
> On 2015-02-03 11:00:43 -0500, Robert Haas wrote:
>> Could we, maybe, even make it a derived value rather than one that is
>> explicitly configured? Like, if you set max_wal_senders>0, you automatically get
>> wal_level=hot_standby?

> Our experience with derived gucs isn't that great. Remember the whole
> effective_cache_size mess? Maybe we just need to find a better way to
> implement that though, instead of avoiding it from here on.

We've proven that it's a bad idea to have a GUC whose default value
depends on another one. However, I thought the proposal here was
to get rid of wal_level as a user-visible knob altogether. That
seems like a fine idea if we can drive the decision off other GUCs
instead.

regards, tom lane