Re: Error while creating subscription when server is running in single user mode

On 6/1/17 21:55, Andres Freund wrote:
> On 2017-06-01 21:42:41 -0400, Peter Eisentraut wrote:
>> We should look at what the underlying problem is before we prohibit
>> anything at a high level.
>
> I'm not sure there's any underlying issue here, except being in single
> user mode.

My point is that we shouldn't be putting checks into DDL commands about
single-user mode if the actual cause of the issue is in a lower-level
system. Not all uses of a particular DDL command necessary use a latch,
for example. Also, there could be other things that hit a latch that
are reachable in single-user mode that we haven't found yet.

So I think the check should either go somewhere in the latch code, or
possibly in the libpqwalreceiver code. Or we make the latch code work
so that the check-for-postmaster-death code becomes a noop in
single-user mode. Suggestions?

--
Peter Eisentraut http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services