t On Tue, Apr 8, 2014 at 3:12 AM, Heikki Linnakangas <hlinnakan...@vmware.com> wrote: > 1. Avoid fmgr and shim overhead > 2. Use strxfrm to produce a pseudo-leading key that's cheaper to compare. > > In that case, these changes need to be analyzed separately. You don't get to > "make up" for the losses by the second part by the gains from the first > part. We could commit just the first part (for 9.5!), and that has to be the > baseline for the second part.
Yes, that's right. Robert already submitted a patch that only did 1) almost 2 years ago. That should have been committed at the time, but wasn't. At the time, the improvement was put at about 7% by Robert. It would be odd to submit the same patch that Robert withdrew already. Why shouldn't 2) be credited with the same benefits as 1) ? It's not as if the fact that the strxfrm() trick uses SortSupport is a contrivance. I cannot reasonably submit the two separately, unless the second in a cumulative patch. By far the largest improvements come from 2), while 1) doesn't regress anything. -- Peter Geoghegan -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
