17.00 - 17.05 - About Flushing the DBQL Caches Manually - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - Database Administration

Product
Advanced SQL Engine
Teradata Database
Release Number
17.00
17.05
Published
June 2020
Language
English (United States)
Last Update
2021-01-22
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If you need to flush DBQL caches more quickly than the time defined by DBQLFlushRate, take one of the following actions:

  • Reduce the cache size. See Changing DBQL Cache Size.
  • Issue the FLUSH QUERY LOGGING request:


    where flush_option can be:

    Option Name Table Cache Flushed
    ALL DBQLogTbl, DBQLSQLTbl, DBQLStepTbl, DBQLObjTbl, DBQLXMLTbl, DBQLExplainTbl, DBQLXMLLockTbl, DBQLParamTbl,and DBC.ObjectUsage
    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
    USECOUNT DBC.ObjectUsage
    XMLPLAN DBQLXMLTbl
    This request:
    • Requires the EXECUTE privilege on DBC.DBQLAccessMacro
    • Is valid in BTET (Teradata) mode only
    • Cannot be part of a multistatement 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 Teradata Vantage™ - SQL Data Definition Language Syntax and Examples, B035-1144.
  • 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.