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. Greetings, Andres Freund -- Andres Freund http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
