2 Replies Latest reply on Jan 10, 2018 8:47 AM by Joshua Milligan

    Summary of Join Results Sampled?

    Joshua Milligan

      I'm assuming the Join Result in the Summary represents the sampled data result, because here I'm simulating a cross join of 600K records with 20 records and am seeing only around 1M resulting records.

       

      At one point, I saw a "Sampled" indicator, but it has since disappeared, though the number of result records seems to represent a sample.

       

      Can anyone explain what is going on here?

       

       

      Best Regards,

      Joshua

        • 1. Re: Summary of Join Results Sampled?
          Isaac Kunen

          Hi Joshua,

           

          Yes -- precisely. We sample to try to keep the data manageable while you're massaging it, but there are operations like a join that can increase the number of records, so we will apply our sampling logic on top of them as well.

           

          You should absolutely see the "Sampled" badge when this happens -- and this should draw your attention to the fact that the join results may be misleading. If it's not showing up for you here (and if those columns really are all "1" as it appears) then it's definitely a bug.

           

          Cheers,

          -Isaac

          2 of 2 people found this helpful
          • 2. Re: Summary of Join Results Sampled?
            Joshua Milligan

            Isaac,

             

            Thank you!  Yes, I was pretty sure the "Sampled" badge showed up at first, but subsequently disappeared.  Your explanation makes perfect sense and yes, all the values are 1 for both fields.

             

            Best Regards,

            Joshua