On Fri, Dec 12, 2014 at 03:27:33PM +0100, Andres Freund wrote: > On 2014-12-12 09:24:27 -0500, Bruce Momjian wrote: > > On Fri, Dec 12, 2014 at 03:22:24PM +0100, Andres Freund wrote: > > > > Well, the larger question is why wouldn't we just have the user compress > > > > the entire WAL file before archiving --- why have each backend do it? > > > > Is it the write volume we are saving? I though this WAL compression > > > > gave better performance in some cases. > > > > > > Err. Streaming? > > > > Well, you can already set up SSL for compression while streaming. In > > fact, I assume many are already using SSL for streaming as the majority > > of SSL overhead is from connection start. > > That's not really true. The overhead of SSL during streaming is > *significant*. Both the kind of compression it does (which is far more > expensive than pglz or lz4) and the encyrption itself. In many cases > it's prohibitively expensive - there's even a fair number on-list > reports about this.
Well, I am just trying to understand when someone would benefit from WAL compression. Are we saying it is only useful for non-SSL streaming? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + Everyone has their own god. + -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
