Background documentationSample Locate this document in the navigation structure

 

The system uses samples to estimate the SQL optimizer statistics for a table. The default value for the sample size is 20,000 records.

Sample Type and Size for Updating the SQL Optimizer Statistics

Number of Data Records (Sample Type Rows)

Proportion of Data Records as Percentage of all Data Records in the Table (Sample Size Percent)

Description

0

0

The system does not update any statistics for the table.

0 < Number of data records < Number of data records in the table

The default value for the sample size is 20,000 data records.

0 < Percentage of data records < 100 %

For large tables (> 1,000,000 data records) in SAP systems, we recommend a sample size of 5 %.

The system uses the sample size specified to estimate the statistics.

Number of all data records in the table

100 %

The system calculates the statistics. This usually takes much longer than an estimation using a sample.

More Information

Concepts of the Database System, SQL Optimizer Statistics, EXPLAIN Statement

SQL Reference Manual, SAMPLE Definition

Database Administration in CCMS, SQL Optimizer in CCMS, Scheduling Updates of the SQL Optimizer Statistics

SAP Note 927882