On Feb 10, 2010, at 10:28 PM, Greg Smith wrote: > Ben Chobot wrote: >> I'm looking at pg_stat_user_tables in 8.4.2, and I'm confused about >> n_live_tup. Shouldn't that be at least fairly close to (n_tup_ins - >> n_tup-del)? It doesn't seem to be, but I'm unclear why. >> > Insert 2000 tuples. > Delete 1000 tuples. > vacuum > Insert 1000 tuples. These go into the free space the deleted tuples used to > be in. > analyze > > n_tup_ins=3000 > n_tup_del=1000 > n_live_tup=3000
Say what? It's not documented terrible well (http://www.postgresql.org/docs/8.4/interactive/monitoring-stats.html is the best I can find) but I thought n_live_tup was basically the number of tuples visible to a new transaction. If my assumption is wrong, that might explain things. And unfortunately, Tom, we're not resetting stats counters. :(
