Re: min_safe_lsn column in pg_replication_slots view

Alvaro Herrera <alvherre@2ndquadrant.com> writes:
> On 2020-Jul-09, Alvaro Herrera wrote:
>> I think we should define InvalidXLogSegNo to be ~((uint64)0) and add a
>> macro to test for that.

> That's overkill really.  I just used zero.  Running
> contrib/test_decoding under valgrind, this now passes.

> I think I'd rather do away with the compare to zero, and initialize to
> something else in GetWALAvailability, though.  What we're doing seems
> unclean and unclear.

Is zero really not a valid segment number?

            regards, tom lane