On Sun, Oct 26, 2008 at 09:49:49PM -0400, Tom Lane wrote:
> So I'm concluding that we can easily afford to switch to tuplestore-always
> operation, especially if we are willing to put any effort into tuplestore
> optimization. (I note that the current tuplestore code writes 24 bytes
> per row for this example, which is a shade on the high side for only 4 bytes
> payload. It looks like it would be pretty easy to knock 10 bytes off that
> for a 40% savings in I/O volume.)
I thought that the bad case for a tuplestore was if the set returning
function was expensive and the user used it with a LIMIT clause. In the
tuplestore case you evaluate everything then throw it away.
Your test cases, if you append LIMIT 1 to all of them, how do the
timings compare then?
Have a nice day,
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> Please line up in a tree and maintain the heap invariant while
> boarding. Thank you for flying nlogn airlines.