Updating Statistics on a Table

Use SAP Control Center to update column-related statistics, such as histograms and densities.

1. In the Administration Console view, select ASE Servers > Schema Objects > Tables > User Tables.
2. Click the Name field of the table, then click the drop-down arrow and select Update Statistics.
3. On the Command Type screen, select the update statistics command to run.
4. (Optional) On the Data Partitions screen, select Specify a data partition, if applicable, and indicate any data partitions. update statistics runs on all partitions if you do not specify one. Click Next.
5. On the Columns screen, indicate whether:
   • To run update statistics on specific columns.
   • Histograms on all columns (the default).
   • To updates statistics in ordered column grouping. SAP ASE versions earlier than 15.7 ESD #2 support only ordered grouping statistics; the histograms option is unavailable.
6. On the Indexes screen (not available if you selected update all statistics on the Command Type tab, or specified any columns on the Columns tab), indicate any indexes on which to run update statistics. If you do not select any indexes, update statistics updates all indexes.
7. On the Index Partitions screen (visible when you select an index on the Indexes screen), indicate the index partition to update.
8. On the Hashing screen, select:
   • The type of hashing:
     • Partial hashing – for columns that have 65536 or fewer unique values.
     • With hashing – for columns that have greater than 65536 unique values.
     • No hashing.
   • A value for max resource granularity (which indicates the maximum percentage of the system’s resources a query can use), if applicable.
9. On the Histogram Tuning screen, set the histogram tuning factor. The size of the histogram is established by multiplying the number of steps with the value for histogram tuning factor.
10. On the Sampling screen, specify whether to set sampling, and to what percentage.
11. On the Step Number screen, indicate whether to set the number of histogram steps, and if so, how many.
12. On the Consumers screen, set the number of consumer processes to be used in parallel processing. The controls are enabled if the value for max parallel degree is 3 or greater.
13. On the DataChange Threshold screen, indicate whether to run update statistics when it reaches a data change threshold, and if so, the value of the threshold.
14. On the Summary screen, verify your selections.
15. Click Finish.