Hi,
At times it's useful to know the last replayed WAL record's timeline
ID (especially on the standbys that are lagging in applying WAL while
failing over - for reporting, logging and debugging purposes). AFICS,
there's no function that exposes the last replayed TLI. We can either
change the existing pg_last_wal_replay_lsn() to report TLI along with
the LSN which might break the compatibility or introduce a new
function pg_last_wal_replay_info() that emits both LSN and TLI. I'm
fine with either of the approaches, but for now, I'm attaching a WIP
patch that adds a new function pg_last_wal_replay_info().
Thoughts?
Regards,
Bharath Rupireddy.