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
