Can't, it generates huge IO spikes.
But....
Few hours ago i manually started vacuum verbose on pg_attribute, now its finished and i have some outputs:
INFO: "pg_attribute": found 554728466 removable, 212058 nonremovable row versions in 44550921 out of 49326696 pages DETAIL: 178215 dead row versions cannot be removed yet. There were 53479 unused item pointers. 0 pages are entirely empty. CPU 1097.53s/1949.50u sec elapsed 6337.86 sec. Query returned successfully with no result in 01:47:3626 hours.
what do you think?
select count(*) on pg_attribute returns:
158340 rows
So as i understand vacuum full will create new pg_attribute and will wrote those amount of "valid" rows, but still it will scan 300GB old table?
So estimate will be even ~same compering with regular vacuum?