On Wed, 2005-12-07 at 11:01, Alexander Scholz wrote: > Dear NG, > > I have a serious performance flaw, when using postgresql 8.1 (other > versions haven't been tested) with libpq. When executing a > > select * from "xyz" 1) > > and "xyz" contains 300'000 records, it takes more than 60 seconds for > the query just to complete. First I thought it is a performance problem > of the server, but then we noticed an enormous amount of TCP/IP packets > that are beeing received in that (waiting)time. The memory usage of my > process, while waiting for the query to complete, bumps up to more than > 300MB, the CPU usage goes up to 100%! It seems as if libpq would be > receiving the complete resultset from the server _before_ returning from > the query execution! (Even then 300MB seems for me to be too much, but > that's not the point!) Just to ensure: I didn't perform ANY _fetch_ so > far! It's just about executing the query. Yep, libpq is doing exactly what you asked it to do, no more, no less. If you're like your result set to be in a cursor, you'll need to declare one. try declare cursor xyz as select ... fetch 100; and see how that works.
