On Tuesday, July 1, 2014, john gale <j...@smadness.com> wrote: > > What does vacuum have to scan to be able to reclaim space, and how many > times does it need to scan to finalize ? > > More specifically, my VACUUM VERBOSE <table> is taking a long time and > seems to be rescanning the same indexes / fields multiple times without > finishing. >
vacuum can only memorize one dead tuple for every 6 bytes of maintenance_work_mem. If there are more dead tuples than that, it needs to make multiple passes over the indexes. Increase maintenance_work_mem to improve the efficiency. Cheers, Jeff
