On Mon, Jan 5, 2009 at 2:02 PM, Gregory Stark <st...@enterprisedb.com> wrote: >> Regardless of whether we do that or not, no one has offered any >> justification of the arbitrary decision not to compress columns >1MB, > > Er, yes, there was discussion before the change, for instance: > > http://archives.postgresql.org/pgsql-hackers/2007-08/msg00082.php
OK, maybe I'm missing something, but I don't see anywhere in that email where it suggests NEVER compressing anything above 1MB. It suggests some more nuanced things which are quite different. > And do you have any response to this point? > > I think the right value for this setting is going to depend on the > environment. If the system is starved for cpu cycles then you won't want to > compress large data. If it's starved for i/o bandwidth but has spare cpu > cycles then you will. > > http://archives.postgresql.org/pgsql-hackers/2009-01/msg00074.php I think it is a good point, to the extent that compression is an option that people choose in order to improve performance. I'm not really convinced that this is the case, but I haven't seen much evidence on either side of the question. > Well the original code had a threshold above which we *always* compresed even > if it saved only a single byte. I certainly don't think that's right either. ...Robert -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
