On fim, 2006-02-16 at 16:24 -0500, Emi Lu wrote: > >>In another way, whenever we "delete/truncate and then insert" data into > >>a table, it is better to "vacuum anaylze"? > >> > >> > >You shouldn't need a VACUUM if you haven't yet done any updates or > >deletes since the TRUNCATE. An ANALYZE seems like a good idea, though. > >(You could get away without ANALYZE if the new data has essentially the > >same statistics as the old, but if you're making only minor changes, why > >are you using this technique at all ...) > > > > > After truncate table A, around 60,000 will be inserted. Then a > comparision will be done between table A and table B. After that, table > B will be updated according to the comparision result. Records inserted > into table A is increasing everyday. > > So, your suggestion is that after the population of table A, the query > planner should be able to find the most efficient query plan because we > do truncate but not delete, and we do not need to do vacuum analyze at > all, right? no. the suggestion was that a VACUUM is not needed, but that an ANALYZE might be. gnari
