The predefined DBQL logs are created as relational tables in DBC during normal Vantage installation.
For Advanced SQL Engine 17.00 and later, the default mode for DBQL logging is set to Algorithm 3. For upgrades to Release 17.00, the previous setting is retained, although Teradata recommends switching to Algorithm 3 if that was not the previous setting for your environment. To switch to Algorithm 3, change DBS Control General field 64 DBQL CPU/IO Collection, see Setting DBQL Logging Algorithm.
To keep DBQL logging performing optimally, the best practice is to set up a recurring job to offload data to PDCR. See: Maintaining the Logs.
AMPs use a DBQL cache called DBQL Performance Stats (DPS) cache. The DPS cache size is controlled by the DBQL_AWTDPS_CacheMaximum field 37 in the DBS Control Performance section. The default cache size is 8192. If the size needs to be adjusted, see Changing the DBQL Performance Stats Cache Size.
If you choose not to use DBQL logging, the tables remain empty.