Andres Freund 78d6a9cbd3 Fix and improve SnapshotType comments.
The comment for SNAPSHOT_SELF was unfortunately explaining
SNAPSHOT_DIRTY, as reported by Sergei. Also expand a few comments, and
include a few more comments from heapam_visibility.c, so they're in an
AM independent place.

Reported-By: Sergei Kornilov
Author: Andres Freund
Discussion: https://postgr.es/m/9152241558192351@sas1-d856b3d759c7.qloud-c.yandex.net
2019-05-19 16:18:44 -07:00
..
2019-05-09 09:16:59 +02:00
2019-04-26 21:20:55 -04:00