On Thu, Oct 20, 2016 at 12:30 PM, Pavan Deolasee <pavan.deola...@gmail.com> wrote: > > > On Thu, Oct 20, 2016 at 8:44 PM, Petr Jelinek <p...@2ndquadrant.com> wrote: >> >> >> >> WARM can do WARM update 50% of time, indirect index can do HOT update >> 100% of time (provided the column is not changed), I don't see why we >> could not have both solutions. >> > > I think the reason why I restricted WARM to one update per chain, also > applies to indirect index. For example, if a indirect column value is > changed from 'a' to 'b' and back to 'a', there will be two pointers from 'a' > to the PK and AFAICS that would lead to the same duplicate scan issue. > > We have a design to convert WARM chains back to HOT and that will increase > the percentage of WARM updates much beyond 50%. I was waiting for feedback > on the basic patch before putting in more efforts, but it went unnoticed > last CF.
With indirect indexes, since you don't need to insert a tid, you can just "insert on conflict do nothing" on the index. -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers