Gary Doades <gpd@xxxxxxxxxxxx> writes: > Interestingly, if I don't delete the table after a run, but just drop > and re-create the index repeatedly it stays a pretty consistent time, > either repeatedly good or repeatedly bad! This is consistent with the theory of a data-dependent performance problem in qsort. If you don't generate a fresh set of random test data, then you get repeatable runtimes. With a new set of test data, you might or might not hit the not-so-sweet-spot that we seem to have detected. regards, tom lane
