On Mon, Sep 24, 2018 at 05:59:12PM -0700, Vladimir Ryabtsev wrote: > > This seems significant..it means the heap was probably written in > backwards > order relative to the IDs, and the OS readahead is ineffective when index > scanning across a range of IDs. > But again, why is it different for one range and another? It was reversed > for both ranges. I don't have an explaination for it.. but I'd be curious to know pg_stats.correlation for the id column: SELECT schemaname, tablename, attname, correlation FROM pg_stats WHERE tablename='articles' AND column='article_id' LIMIT 1; Justin
