On Tue, May 21, 2019 at 8:27 PM Walter Smith <wal...@carezone.com> wrote:
> On Tue, May 21, 2019 at 11:17 AM Peter Geoghegan <p...@bowt.ie> wrote: > >> On Tue, May 21, 2019 at 11:16 AM Walter Smith <wal...@carezone.com> >> wrote: >> > It occurs to me that is a somewhat unusual index -- it tracks >> unprocessed notifications so it gets an insert and delete for every row, >> and is normally almost empty. >> >> Is it a very low cardinality index? In other words, is the total >> number of distinct keys rather low? Not just at any given time, but >> over time? > > > Very low. Probably less than ten over all time. I suspect the only use of > the index is to rapidly find the processed=false rows, so the > notifiable_type value isn’t important, really. It would probably work just > as well on any other column. > > — Walter > > > >
