Nice write-up. Something does not add up here though. Primary writes 32 ahead to the WAL when fetched the first time, then keeps a counter (log_cnt) which it decreases each time nextval is called. So, when sequence was initialized, nextval is 1 and WAL has 32. The replica sees 32 as fetched offset. How does incident sequence switch from 7 to 39? Shouldn't it be 33 when the replica was made the primary? Same for incident 20 -> 52, shouldn't it be 33 when replica was made primary? Unless I am missing something here, i.e, 32 is added to the nextval and nextval is logged each time (20 or 7).