On Wed, Jun 07, 2006 at 12:57:15PM -0500, Tim Hart wrote: > Could custom types benefit significantly from custom operators as > well? Yes. > Do custom C functions stand a good chance of introducing speed > benefits over their raw SQL or pl/sql counterparts? Or is the field > too broad to speculate on the general case? Generally, it's too broad to say. Note also that programmer time is a valuable resource and CPU time is cheap. > The scenario that inspired this question was about data that had to > be stored accurately, but the data itself wasn't usually precise. > You could think of an individual datum being a set of ranges. You > could definitely define equality on this data type, but the ordering > operators would probably be meaningless. Right. Just don't define a < or > operator, but do define an = operator on the type :) > On the other hand, some (but not all) of the geometric operators could > probably be interpreted to apply to this data set, as long as you ignore the > 'above' and 'below' semantics, and replace the concepts of left and right > with less than and greater than. So for example, while > > << (is strictly left of) > > Wouldn't make sense, using the same operator to mean 'strictly less than' > might. > > Would R-tree indexes be useful for a data type like this? Would it > be possible to define the base type such that an R-tree index would > always be created? Kinda depends on what you're doing. > Once again - this is entirely idle curiosity. This isn't anything I > have a real need for. You might some day. One of PostgreSQL's Killer Features(TM) is its radical extensibility. Cheers, D -- David Fetter <david@xxxxxxxxxx> http://fetter.org/ phone: +1 415 235 3778 AIM: dfetter666 Skype: davidfetter Remember to vote!
