Martijn van Oosterhout <kleptog@svana.org> writes:
> However, postgres tables are very highly compressable, 10-to-1 is not
> that uncommon. pg_proc and pg_index compress by that for example.
> Indexes compress even more (a few on my system compress 25-to-1 but
> that could just be slack space, the record being 37-to-1
> (pg_constraint_conname_nsp_index)).
Anything containing a column of type "name" will compress amazingly well
because of all the padding spaces. I don't think that's representative
of user data though ... except maybe for the occasional novice using
"char(255)" ...
regards, tom lane