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
