select actual data size for a relation?

Hi all;

Anyone know how to select / calculate the actual data size for a table or
index?

NOT the disk usage as in:
 pg_class.relpages -- shows disk usage including bloat
pg_relation_size() -- same as pg_class.relpages but in bytes
or pg_total_relation_size()  -- total disk usage inclusive of bloat and
indexes

I want only the data size. I tried grabbing the sum of all the avg_width cols
from pg_stats and multiplying times the pg_class.reltuples but this seems way
too big.

Thoughts?



Thanks in advance