Edmund Horner <ejr...@gmail.com> writes: > [ tid scan patches ] I'm having a hard time wrapping my mind around why you'd bother with backwards TID scans. The amount of code needed versus the amount of usefulness seems like a pretty bad cost/benefit ratio, IMO. I can see that there might be value in knowing that a regular scan has "ORDER BY ctid ASC" pathkeys (mainly, that it might let us mergejoin on TID without an explicit sort). It does not, however, follow that there's any additional value in supporting the DESC case.
regards, tom lane