EXPLAIN Output for Aggregate Functions | Teradata Vantage - 17.00 - EXPLAIN Statement Output for Time Series Aggregate Functions - Teradata Database

Teradata Vantageā„¢ - Time Series Tables and Operations

Advanced SQL Engine
Teradata Database
June 2020
Programming Reference

The output of the EXPLAIN statement includes information about time zero when using VERBOSE EXPLAIN; for example:

We begin the time series aggregate calculation using
     time zero <time_zero> 

<time_zero> displays the type and constant value calculated as the time zero to use for a GROUP BY TIME query (such as, TIMESTAMP '2014-01-06 08:00:00.000000+00:00' ). This information appears in the SUM step of the EXPLAIN output.

Other information about time series queries can be deduced from the current EXPLAIN output:

  • Information about which optimization plan for single threaded aggregate execution is in use
  • Specification of each aggregate function as fully parallel or single threaded
  • Specification of any sorting or redistribution performed prior to the aggregation (this is important for single threaded aggregate evaluation)
  • Specification of any sorting or redistribution performed after the aggregation (this is important for FILL directive evaluation)
  • Execution of FILL directive prints (fill empty groups in the time series with <value>).