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