Re: libpq compression

On 16.05.2018 18:09, Grigory Smolkin wrote:
>
> Hello!
> I have noticed that psql --help lack -Z|--compression option.
> Also it would be nice to have option like --compression-level in psql 
> and pgbench.
>
Thank you for this notice.
Updated and rebased patch is attached.
Concerning specification of compression level: I have made many 
experiments with different data sets and both zlib/zstd and in both 
cases using compression level higher than default doesn't cause some 
noticeable increase of compression ratio, but quite significantly reduce 
speed. Moreover, for "pgbench -i" zstd provides better compression ratio 
(63 times!) with compression level 1 than with with largest recommended 
compression level 22! This is why I decided not to allow user to choose 
compression level.