Limits the size to which the per-AMP AWT DBQL Performance Stats (DPS) cache can grow. This cache holds DBQL request and step data for active requests.
Field Group
Performance
Valid Range
1024 to 16384 KB
1024 KB holds approximately 2,500 cache entries.
Default
8192 KB
Changes Take Effect
After the DBS Control Record has been written.
Usage Notes
- When the cache has grown to the set maximum size, no further DBQL AMP data is cached, and the accuracy of query performance statistics can degrade.
- If you reduce the size of the cache maximum to something below the current actual size of the cache, the current cache will neither shrink nor grow, but space in the current cache can be dynamically reused. The memory currently allocated to the cache is not released until the next database restart.
- If you see a 9666 information event logged to /var/log/messages, you should increase the value of this field.
- Teradata recommends you increase the value of this field in 4096 KB (4 MB) increments.
Related Information
| For more information on… | See… |
|---|---|
| BEGIN QUERY LOGGING, END QUERY LOGGING, and FLUSH QUERY LOGGING statements | SQL Data Definition Language Syntax and Examples, B035-1144. |
| tracking processing behavior with the DBQL | Database Administration, B035-1093. |