The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/10/auth-pg-hba-conf.html
Description:
I've been setting up logical replication today and I had a lot of trouble
getting it to work. The main issue I ran into was that I mistakenly had the
database set to "replication," thinking that logical replication required
that keyword the same way physical replication does.
When you do this, and then try to create a subscription, you get an error
like:
ERROR: could not connect to the publisher: FATAL: no pg_hba.conf entry for
replication connection from host "73.71.60.29", user "testreplicator", SSL
on
FATAL: no pg_hba.conf entry for replication connection from host
"73.71.60.29", user "testreplicator", SSL off
Hm. Somehow you can't connect. Well, it's because you are trying to do
logical replication and the only connection config you have is for physical
replication. The error message isn't great, and so I burned a good bit of
time trying to figure out what the heck was going on.
Anyway, I suggest a quick change to add emphasis about how the replication
keyword should not be used for logical replication. That'd have saved me.
In a really wonderful world, we could also:
- Update the pg_hba.conf file to make a note about this, and
- Improve the error message above somehow to indicate that it only sees
physical replication slots or something like that (I'm not sure what's
possible here.)
I hope this helps, and thank you for all the rest of the wonderful
documentation.