Patent ID: 11880366
Assignee: SAP SE
Field: Computer technology (Electrical engineering)
Classification: CPC G | IPC G

Claim 10:
11. A computing system configured to execute computer-readable instructions for performing join size estimation operations, the operations comprising:
for a join operation between a first table, to which a filter has been applied, and a second table, performing iterations until a statistical confidence in a join factor for the join operation has been reached, the iterations comprising:
using a sample size, sampling a filter output of the filter to generate a filtered sample, the filtered sample comprising a sample size number of records from the filter output;
for records in the filtered sample, accessing an index for the second table and retrieving counts of records in the second table corresponding to the records in the filtered sample;
calculating the join factor based on the counts of records in the second table corresponding to the records in the filtered sample and the sample size of the filtered sample; and
upon determining that a statistical confidence in the join factor has not yet been reached, determining a new value for the sample size for a next iteration;

estimating a data size for the join operation using the join factor; and
based on the estimated data size for the join operation, determining or modifying a query execution plan incorporating the join operation as part of query optimization.