On Tue, Dec 6, 2016 at 6:57 PM, Masahiko Sawada <sawada.m...@gmail.com> wrote: > On Tue, Dec 6, 2016 at 1:11 PM, Fujii Masao <masao.fu...@gmail.com> wrote: >> If M (i.e., number of quorum sync standbys) is enough large, >> your choice would be good. But usually M seems not so large. >> > > Thank you for the comment. > > One another possible idea is to use the partial selection sort[1], > which takes O(MN) time. Since this is more efficient if N is small > this would be better than qsort for this case. But I'm not sure that > we can see such a difference by result of performance measurement. > > [1] https://en.wikipedia.org/wiki/Selection_algorithm#Partial_selection_sort
We'll begin to see a minimal performance impact when selecting a sync standby across hundreds of them, which is less than say what 0.1% (or less) of existing deployments are doing. The current approach taken seems simple enough to be kept, and performance is not something to worry much IMHO. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
