Michael Fuhr wrote: > On Wed, Mar 09, 2005 at 02:02:13AM +0100, Gaetano Mendola wrote: > > >>Basically I'm noticing that a simple vacuum full is not enough to >>shrink completelly the table: >> >># vacuum full verbose url; >>INFO: vacuuming "public.url" >>INFO: "url": found 268392 removable, 21286 nonremovable row versions in 8563 >>pages >>DETAIL: 22 dead row versions cannot be removed yet. > > > How busy is the database? I'd guess that each time you run VACUUM, > there are still open transactions that have visibility to the dead > rows, so VACUUM doesn't touch them. Those transactions eventually > complete, and eventually VACUUM FULL does what you're expecting. > I don't know if that's the only possible cause, but I get results > similar to yours if I have transactions open when I run VACUUM. >
That was my first tough but it seem strange that 2 dead rows where grabbing 7883 pages, don't you think ? # vacuum full verbose url; INFO: vacuuming "public.url" INFO: "url": found 74 removable, 21266 nonremovable row versions in 8550 pages DETAIL: 2 dead row versions cannot be removed yet. [SNIP] INFO: "url": moved 11 row versions, truncated 8550 to 8504 pages and in the next run: # vacuum full verbose url; INFO: vacuuming "public.url" INFO: "url": found 13 removable, 21264 nonremovable row versions in 8504 pages DETAIL: 0 dead row versions cannot be removed yet. [SNIP] INFO: "url": moved 5666 row versions, truncated 8504 to 621 pages Regards Gaetano Mendola ---------------------------(end of broadcast)--------------------------- TIP 8: explain analyze is your friend
