Sap Se

Axel Hertzschuch

Norman May

Wolfgang Lehner

Lars Fricke

Guido Moerkotte

Florian Wolf

A system includes determination of a plurality of queries of a workload, determination of a data source comprising a plurality of data rows, and determination of a sample data source based on a cardinality of each of the plurality of queries with respect to the data source and an estimated cardinality of each of the plurality of queries with respect to the data source, wherein the estimated cardinality of a query with respect to the data source is determined based on the sample data source.

Workload-based sampling

A system includes determination of a query on a table, the query including a first predicate and a second predicate, determination of a sample of the table, the sample comprising a plurality of tuples of the table, determination of a first conditional probability of selecting a tuple of the sample satisfying the first predicate and the second predicate, determination of a second conditional probability of selecting a tuple of the sample satisfying the first predicate and not satisfying the second predicate, adjustment of the first conditional probability based on the second conditional probability, a number of tuples of the sample satisfying the second predicate, a number of tuples of the sample not satisfying the second predicate, and a number of tuples of the sample satisfying the first predicate and not satisfying the second predicate, and determination of a selectivity of the query on the table based on the first adjusted conditional probability.

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Dresden, Germany

Axel Hertzschuch