16.10 - About Flushing the DBQL Cache Manually - Teradata Database

Teradata Database Administration

Product
Teradata Database
Release Number
16.10
Release Date
April 2018
Content Type
Administration
Publication ID
B035-1093-161K
Language
English (United States)

If you need to flush DBQL caches more quickly than the time defined by DBQLFlushRate, either:

  • Issue the FLUSH QUERY LOGGING request:

    where flush_option can be:

    Option Name Table Cache Flushed
    ALLDBQL DBQLogTbl, DBQLSQLTbl, DBQLStepTbl, DBQLObjTbl, DBQLXMLTbl, DBQLExplainTbl, DBQLXMLLockTbl, and DBQLParamTbl
    DEFAULT DBQLogTbl
    EXPLAIN DBQLExplainTbl
    LOCK DBQLXMLLockTbl
    OBJECTS DBQLObjTbl
    PARAMINFO DBQLParamTbl
    SQL DBQLSQLTbl
    STEPINFO DBQLStepTbl
    SUMMARY DBQLSummaryTbl
    XMLPLAN DBQLXMLTbl

This request:

  • Requires the EXECUTE privilege on DBC.DBQLAccessMacro
  • Is valid in BTET (Teradata) mode only
  • Cannot be part of a multi-statement request
  • Cannot be used in a stored procedure
    This request is especially recommended when a system is not busy and caches are not filling up and written to Data Dictionary tables as frequently.

    This request can also flush Teradata dynamic workload management software caches. Only the DBQL options are described here. For the Teradata dynamic workload management software options, see SQL Data Definition Language Syntax and Examples.

  • Or reset the value in the DBQLFlushRate to a faster rate.
    Changes to DBQLFlushRate also causes the summary/threshold cache to flush, which causes the summary/threshold collection time interval to change.