On Thu, Jun 14, 2018 at 4:56 PM Claudio Freire <klaussfre...@gmail.com> wrote: > Not at all. Insertion cost in unique indexes with lots of duplicates > (happens, dead duplicates) grows quadratically on the number of > duplicates, and that's improved by making the index unique and sorted.
Sorry, I've messed up the terms. I did actually compare current non-unique indexes with non-unique indexes keeping duplicate entries ordered by TID (which makes them somewhat unique). I didn't really considered indexes, which forces unique constraints. For them insertion cost grows quadratically (as you mentioned) independently on whether we're keeping duplicates ordered by TID or not. ------ Alexander Korotkov Postgres Professional: http://www.postgrespro.com The Russian Postgres Company
