On Thu, May 17, 2018 at 3:54 AM, Konstantin Knizhnik <k.knizh...@postgrespro.ru> wrote: > 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.
Speaking of configuration, are you planning to support multiple compression libraries at the same time? It looks like the current patch implicitly requires client and server to use the same configure option, without any attempt to detect or negotiate. Do I guess correctly that a library mismatch would produce an incomprehensible corrupt stream message? -- Thomas Munro http://www.enterprisedb.com
