c8ba697a4b
Every time the best-tuple-found-so-far changes, we need to reset all the penalty values in which_grow[] to the penalties for the new best tuple. The old code failed to do this, resulting in inferior index quality. The original patch from Alexander Korotkov was just two lines; I took the liberty of fleshing that out by adding a bunch of comments that I hope will make this logic easier for others to understand than it was for me.
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