"Kevin Grittner" <Kevin.Grittner@wicourts.gov> writes:
> One thing I've been wondering about is what, exactly, is compressed in
> custom format. Is it like a .tar.gz file, where the compression is a
> layer over the top, or are individual entries compressed?
Individual entries. Eyeball examination of a dump file shows that we
only compress table-data entries, and don't for example waste time
firing up the compressor to process a function body. It's possible
that it'd be worth trying to have some lower limit on the amount of
data in a table before we bother to compress it, but I bet that it
wouldn't make any difference on your databases ...
regards, tom lane