Containment (Simple) vs Containment (base):

sakuraime 2,326 Reputation points
2020-08-26T07:49:22.277+00:00

Containment (Simple) vs Containment (base):
Containment (Simple): Users query for data that exists. For example, for an equality join between two tables, factor in the predicates selectivity1 in each input histogram, before joining histograms to estimate the join selectivity

Simple Containment becomes Base Containment: Users might query for data that does not exist. For example, for an equality join between two tables, we use the base tables histograms to estimate the join selectivity, and then factor in the predicates selectivity.

still confusing what's the difference . any example ?

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  1. Erland Sommarskog 110.3K Reputation points
    2020-08-26T21:59:58.703+00:00

    So have you read Joe Sack's white paper on the new cardinality estimator yet?
    https://video2.skills-academy.com/en-us/previous-versions/dn673537(v=msdn.10)?redirectedfrom=MSDN

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  2. sakuraime 2,326 Reputation points
    2020-08-28T17:19:37.053+00:00

    so it's only applicable to "inner join" , the examples are inner joins

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