Re: Add hint about replication slots when nearing wraparound

On Wed, Dec 20, 2017 at 12:46 AM, Robert Haas <robertmhaas@gmail.com> wrote:
> On Tue, Dec 19, 2017 at 5:27 AM, Feike Steenbergen
> <feikesteenbergen@gmail.com> wrote:
>> While doing some wraparound debugging, I saw the hint regarding upcoming
>> wraparound did not include the problem of having a stale replication
>> slot (which I'm actually using to force wraparound issues).
>>
>> I remember a few discussions where a stale replication slot was actually the
>> culprit in these situations.
>>
>> Something like the attached maybe?
>
> +1.

+1.

prepare_transaction.sgml has a "Caution" block mentioning that it is
unwise to keep 2PC transactions unfinished for a too-long time as it
interferes with VACUUM. In doc/src/sgml/logicaldecoding.sgml, it would
be nice to add the a similar caution notice about replication slots so
as users can get be warned before a wraparound shows up.
-- 
Michael