"Kevin O'Gorman" <kogorman(at)pacbell(dot)net> writes:
> I've got 33150 rows which the EXPLAIN said at top level would be
> 80-byte rows. VACUUM indicates 488 pages. Does this compute?
Keep in mind that EXPLAIN's estimates of average row width are almost,
but not quite, entirely bogus. I'm actually quite surprised that your
arithmetic produced a number as close to 8K as it did.
We need to start keeping stats about the average width of variable-
length columns; until we do, EXPLAIN can't possibly produce row width
estimates that are at all accurate.
regards, tom lane