On Nov 17, 2011 1:32 PM, "Tom Lane" <t...@sss.pgh.pa.us> wrote: > > John R Pierce <pie...@hogranch.com> writes: > > On 11/16/11 4:24 PM, Jason Buberel wrote: > >> Just wondering if there is ever a reason to vacuum a very large table > >> (> 1B rows) containing rows that never has rows deleted. > > > no updates either? > > To clarify: in Postgres, an "update" means an insert and a delete. > So unless you mean that this table is insert-only, you certainly > still need vacuum. > > > you still want to do a vacuum analyze every so often to update the > > statistics used by the planner. > > If it's purely an insert-only table, such as a logging table, then in > principle you only need periodic ANALYZEs and not any VACUUMs. >
Won't a VACUUM FREEZE (or autovac equivalent) be necessary eventually, to handle xid wraparound? If so, doing it pre-emptively might help avoid a giant I/O load and work pause when its forced. Or am I just confused?
