Re: Autovacuum fails to keep visibility map up-to-date in mostly-insert-only-tables

It is only a page read if you have to read the page.  It would seem optimal to have bgwriter adventitiously set hint bits and vm bits, because that is the last point at which the page can be changed without risking that it be written out twice. At that point, it has been given the maximum amount of time it can be given for the interested transactions to have committed and to have aged past the xmin horizon.  I seem to recall that the main problem with that, though, is that you must be attached to a database in order to determine visibility, and bgwriter is not attached to a database.

Cheers,

Jeff