On Mon, Oct 4, 2010 at 2:58 AM, Dean Rasheed <dean.a.rash...@gmail.com> wrote: > That requires a new sort for each row. I generated this with a minor > tweak to Pavel's patch to just restart the tuplesort each time (the > "quick-fix" solution). The problem is that performance really sucks, > because it is an O(n^2 log(n)) algorithm.
Maybe that's OK. If you're doing repeated median operations on large data sets, perhaps you should expect that to be slow. I bet that people who want to use this as a window function will want one median per group, not n medians per group; and it doesn't seem like a good idea to say - we're not going to let you use this as a window function AT ALL because you might decide to do something that will be really slow. You can always hit ^C if you get tired of waiting. This seems like it's very far from being the most important thing for us to optimize, though of course it's great if we can. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise Postgres Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
