GZIP of pre-zipped output

If you are really so desparate to save a couple of GB that you are resorting
to -Z9 then I'd suggest using bzip2 instead.

bzip is designed for things like installer images where there will be
massive amounts of downloads, so it uses a ton of cpu during compression,
but usually less than -Z9 and makes a better result.

Cheers
Dave

On Mar 21, 2010 10:50 AM, "David Newall" <postgresql(at)davidnewall(dot)com> wrote:

Tom Lane wrote:
>
> I would bet that the reason for the slow throughput is that gzip
> is fruitlessl...
Indeed, I didn't expect much reduction in size, but I also didn't expect a
four-order of magnitude increase in run-time (i.e. output at 10MB/second
going down to 500KB/second), particularly as my estimate was based on
gzipping a previously gzipped file. I think it's probably pathological
data, as it were. Might even be of interest to gzip's maintainers.