anitchakkarwar(at)gmail(dot)com writes:
> If I do truncate then n_tup_del value is 0 but all the rows are deleted from
> table.
> Is this something expected behaviour ?
Yes. We're certainly not going to make TRUNCATE update that count, since
that would require making a pass over the table to count the to-be-deleted
tuples, and the whole point of TRUNCATE is to not make a pass over the
table.
regards, tom lane