Re: almost-super-user problems that we haven't fixed yet

On 1/19/23 2:44 AM, Nathan Bossart wrote:
> On Wed, Jan 18, 2023 at 02:51:38PM -0500, Robert Haas wrote:
>> Should (nfree < SuperuserReservedBackends) be using <=, or am I confused?
> I believe < is correct.  At this point, the new backend will have already
> claimed a proc struct, so if the number of remaining free slots equals the
> number of reserved slots, it is okay.
>
>> What's the deal with removing "and no new replication connections will
>> be accepted" from the documentation? Is the existing documentation
>> just wrong? If so, should we fix that first? And maybe delete
>> "non-replication" from the error message that says "remaining
>> connection slots are reserved for non-replication superuser
>> connections"? It seems like right now the comments say that
>> replication connections are a completely separate pool of connections,
>> but the documentation and the error message make it sound otherwise.
>> If that's true, then one of them is wrong, and I think it's the
>> docs/error message. Or am I just misreading it?
> I think you are right.  This seems to have been missed in ea92368.  I moved
> this part to a new patch that should probably be back-patched to v12.
>
> On that note, I wonder if it's worth changing the "sorry, too many clients
> already" message to make it clear that max_connections has been reached.
> IME some users are confused by this error, and I think it would be less
> confusing if it pointed to the parameter that governs the number of
> connection slots.  I'll create a new thread for this.
>
There is  one typo , for the doc changes, it is  mentioned
"pg_use_reserved_backends" but i think it supposed to be
"pg_use_reserved_connections"
under Table 22.1. Predefined Roles.

[edb@centos7tushar bin]$ ./psql postgres -U r2

psql: error: connection to server on socket "/tmp/.s.PGSQL.5432" failed: FATAL:  remaining connection slots are reserved for roles with privileges of pg_use_reserved_backends