On Fri, May 1, 2015 at 5:27 PM, Andrew Gierth <and...@tao11.riddles.org.uk> wrote: > Also as I've pointed out, it's not even clear that there is a regression > at all, since I've already shown that changes of several percent in > timings of sort operations can be caused by irrelevant noise factors. > To actually show a performance regression of less than 10% or so would > require, at a minimum, showing two different timings using the same data > and the same binary, though even that is subject to noise; to really > prove it you'd have to show a statistically significant difference > between sets of binaries with random padding sizes (see the graph I > posted on this point).
I think the issue is somewhat confused by the fact that there was performance investigation work done on the thread, and a regression was investigated (a regression that has since been fixed). This was a problem that had nothing in particular to do with the Datum tuplesort abbreviation patch, though. -- 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
