There's something a little different that happens during DELETE instead. Close out any open sessions you might have with unfinished transactions seen before. Now, let's start another transaction to delete a row:
postgres=# BEGIN; BEGIN postgres=# DELETE FROM t WHERE s=1; DELETE 1 postgres=# SELECT * from t; s | i ---+--- (0 rows)
Once again, if you look at this table from another session, because it's not been committed yet, the row deleted here will still be there, just with an xmax value set:
$ psql -c "SELECT *,xmin,xmax FROM t;" s | i | xmin | xmax ---+-----+--------+-------- 1 | 101 | 158213 | 158214
Only in the first session has the row been deleted. This brings us to a second form of visibility that needs to be considered: ...
