16.20 - DBQL: Flush Object Use Count - Teradata Vantage NewSQL Engine

Teradata Vantage™ NewSQL Engine Release Summary

prodname
Teradata Database
Teradata Vantage NewSQL Engine
vrm_release
16.20
created_date
March 2019
category
Release Notes
featnum
B035-1098-162K

A FLUSH QUERY LOGGING request now supports the USECOUNT option, which writes cached object use counts to the Data Dictionary ObjectUsage table. USECOUNT is not included in the ALLDBQL option. USECOUNT is included in the ALL option.

Benefits

Users can now flush the object use count cache whenever their applications require it instead of waiting for the 10-minute system default period to expire or for the cache to become full.

Considerations

  • To preserve the performance benefits of caching data, use the USECOUNT option only where needed.
  • If the majority of users or applications need the object use count cache flushed more frequently than the 10-minute system default, lower the value of the DBS Control parameter ObjectUseCountCollectRate instead.
  • The cache flush can take a few seconds to complete, depending on how busy the system is. Users should account for this potential delay when querying rows in the DBC.ObjectUsage table.
  • The USECOUNT option does not reset the system counts used by the COLLECT STATISTICS statement.

SQL Changes

The following SQL statement now accepts the USECOUNT option: FLUSH QUERY LOGGING.

Additional Information

For more information, see Teradata Vantage™ - Database Administration, B035-1093 or Teradata Vantage™ SQL Data Definition Language Syntax and Examples, B035-1144.