On Fri, Jun 5, 2015 at 10:22 AM, Andres Freund <andres@anarazel.de> wrote:
> > Maybe I'm missing something, which functions do you have in mind exactly?
pg_logical_slot_get_changes() etc?
Oh, totally forgot about these. However there are two significant differences between using the functions and using START_REPLICATION command:
1. With get/peek_changes one cannot specify start_lsn. A parameter upto_lsn is supported instead.
2. The functions return when either of the upto_* limits is reached or there are no more data to decode, while with internal command it should wait for more data until interrupted by user.
Anyway, using pg_recvlogical is perfectly fine by me, it's just psql can pass the command, but is not ready to handle the request. Maybe just having are more sensible error message for PGRES_COPY_BOTH is the way to go.
