On Sat, Sep 9, 2017 at 8:28 AM, Greg Stark <st...@mit.edu> wrote: > This may be a bit "how long is a piece of string" but how do those two > compare with string sorting in an interesting encoding/locale -- say > /usr/share/dict/polish in pl_PL for example. It's certainly true that > people do sort text as well as numbers.
I haven't looked at text, because I presume that it's very rare for tuples within a table to be more or less ordered by a text attribute. While the traditional big advantage of replacement selection has always been its ability to double initial run length on average, where text performance is quite interesting because localized clustering still happens, that doesn't really seem relevant here. The remaining use of replacement selection is expressly only about the "single run, no merge" best case, and in particular about avoiding regressions when upgrading from versions prior to 9.6 (9.6 is the version where we began to generally prefer quicksort). > Also, people often sort on > keys of more than one column.... Very true. I should test this. -- 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
