Re: Libpq support to connect to standby server as priority

Tom Lane wrote:
> > As it is now, the patch doesn't keep two connections open.  It remembers
> > the index of the host of the first successful writable connection, but
> > closes the connection, and opens another one to that host if no read-only
> > host can be found.
> 
> Oh!  The reason I assumed it wasn't doing that is that such a behavior
> seems completely insane.  If the point is to keep down the load on your
> master server, then connecting only to immediately disconnect is not
> a friendly way to do that --- even without counting the fact that you
> might later come back and connect again.

That's why I had argued initially to keep the session open, but you
seem to dislike that idea as well.

> If that's the best we can do, we should forget the whole feature and
> just recommend putting slave servers first in your hosts list when
> you want prefer-slave.

If you know which is which, certainly.
But in a setup with automated failover you cannot be certain which is which.
That's what the proposed feature targets.

Yours,
Laurenz Albe