Re: B-Tree support function number 3 (strxfrm() optimization)

On Thu, Sep 25, 2014 at 1:36 PM, Robert Haas  wrote:
> (concerns about a second sortsupport state)

I think I may have underestimated the cost of not have
sorttuple.datum1 with a pointer-to-text representation available in
cases such as the one you describe.

Attached revision introduces an alternative approach, which does not
have a separate sortsupport state struct. In the event of aborting
abbreviation, we go back and fix-up datum1 to have a consistently have
a pointer to text representation, making a comparator swap safe - at
that point, it's as if abbreviation was never even considered (apart
from the cost, of course). We still need a special tie-breaker
comparator, though.

I hope this addresses your concern.

-- 
Peter Geoghegan