The diagnostic functions for VisibilityMap (VM).
This function shows the value recoreded in the visibility map for given page.
This function shows the value recoreded in the visibility map for all page of relation.
$ cd pg_visibilitymap
$ make USE_PGXS=1
# make USE_PGXS=1 install
$ psql
=# CREATE EXTENSION pg_visibilitymap;
CREATE EXTENSION
pg_visibilitymap has been built and tested on;
OS : Linux
DBMS : PostgreSQL 9.3 or later