Hello,
I've changed the BEGIN WAIT FOR LSN statement to core functions
pg_waitlsn, pg_waitlsn_infinite and pg_waitlsn_no_wait.
Currently the functions work inside repeatable read transactions, but
waitlsn creates a snapshot if called first in a transaction block, which
can possibly lead the transaction to working incorrectly, so the
function gives a warning.
Usage examples
==========
select pg_waitlsn(‘LSN’, timeout);
select pg_waitlsn_infinite(‘LSN’);
select pg_waitlsn_no_wait(‘LSN’);
