In data warehouse scenarios where you constantly load in new data every night, and then go query the data you just loaded, you often get really bad execution plans. We explain why.

2 Comments. Leave new

  • I just want to clarify my understanding. When you added the extra 20000 rows, the modification count changed but the statistics did not update? So was the new Cardinality Estimator using the modification count to make its estimate, without knowing anything about the rows that were actually added? And the old Cardinality Estimator still estimated 1 row because it didn’t take into account the modification count at all?

    Reply
  • Mark Armstrong
    March 18, 2019 9:39 pm

    And waiting …
    And wait …
    Zzzzzz

    Reply

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