I wrote:
> It looks like the immediate problem can be resolved by just adding
> a check for conn->pghost not being NULL,
... scratch that. There's another problem here, which is that this
code should not be looking at conn->pghost AT ALL. That will do the
wrong thing with a multi-element host list. The right thing to be
looking at is conn->connhost[conn->whichhost].host --- with a test
to make sure it's not NULL or an empty string. (I didn't stop to
study this code close enough to see if it'll ignore an empty
string without help.)
regards, tom lane