On Thu, Mar 15, 2012 at 3:14 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On Wed, Mar 14, 2012 at 6:06 PM, Daniel Farina <dan...@heroku.com> wrote: > >> If we're curious how it affects replication >> traffic, I could probably gather statistics on LZO-compressed WAL >> traffic, of which we have a pretty huge amount captured. > > What's the compression like for shorter chunks of data? Is it worth > considering using this for the libpq copy protocol and therefore > streaming replication also?
The overhead is between 1 and 5 bytes that reserve the high bit as a continuation bit (so one byte for small data), and then straight into data. So I think it could be applied for most payloads that are a few bytes wide. Presumably that could be lifted, but the format description only allows for 2**32 - 1 for the uncompressed size. I'd really like to find a way to layer both message-oblivious and message-aware transport under FEBE with both backend and frontend support without committing the project to new code for-ever-and-ever. I guess I could investigate it in brief now, unless you've already thought about/done some work in that area. -- fdr -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
