Re: Designing an extension for feature-space similarity search

Alexander Korotkov wrote:
> On Fri, Feb 17, 2012 at 11:32 PM, Jay Levitt <jay.levitt@gmail.com

>     Ah, yes, exactly the same problem. So what led you to add a flag instead
>     of using the range NULL..NULL? I'm on the fence about choosing.
>
>
> At first, range bounds can't be NULL :) At second, if we have range
> (a;b)+"contain empty" in internal page, both facts:
> 1) All normal underlying ranges are contained in (a;b).
> 2) There can be empty underlying ranges.
> are useful for search.

That makes sense; you're essentially keeping one bit of stats about the 
values present in the range.

I wonder: if I'm indexing a rowtype, then for each column in the row I need 
to store a lower-left and an upper-right bound, plus a might-have-nulls 
flag.  Sounds a lot like a range. Should I just use ranges for that? See a 
downside (overhead)? See an upside (seems less duplicative somehow)? I'm 
fine depending on 9.2.

Jay