Re: COPY FREEZE and setting PD_ALL_VISIBLE/visibility map bits

The following review has been posted through the commitfest application:
make installcheck-world:  not tested
Implements feature:       not tested
Spec compliant:           not tested
Documentation:            not tested

This patch is particularly helpful in processing OpenStreetMap Data in PostGIS.
OpenStreetMap is imported as a stream of 300-900 (depending on settings) gigabytes, that are needing a VACUUM after a
COPYFREEZE.
 
With this patch, the first and usually the last transforming query is performed much faster after initial load.

I have read this patch and have no outstanding comments on it.
Pavan Deolasee demonstrates the expected speed improvement.

The new status of this patch is: Ready for Committer