On Thu, Mar 7, 2019 at 12:37 AM Peter Geoghegan <p...@bowt.ie> wrote: > When I drew you that picture while we were in Lisbon, I mentioned to > you that the patch sometimes used a sentinel scantid value that was > greater than minus infinity, but less than any real scantid. This > could be used to force an otherwise-equal-to-pivot search to go left > rather than uselessly going right. I explained this about 30 minutes > in, when I was drawing you a picture.
I meant the opposite: it could be used to go right, instead of going left when descending the tree and unnecessarily moving right on the leaf level. As I said, moving right on the leaf level (rather than during the descent) should only happen when it's necessary, such as when there is a concurrent page split. It shouldn't happen reliably when searching for the same value, unless there really are matches across multiple leaf pages, and that's just what we have to do. -- Peter Geoghegan
