EXPLAIN Request Modifier - Analytics Database - Teradata Vantage

Temporal Table Support

Deployment
VantageCloud
VantageCore
Edition
Enterprise
IntelliFlex
VMware
Product
Analytics Database
Teradata Vantage
Release Number
17.20
Published
June 2022
Language
English (United States)
Last Update
2023-10-30
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lifecycle
latest
Product Category
Teradata Vantage™

You can use the EXPLAIN, STATIC EXPLAIN, and DYNAMIC EXPLAIN request modifiers to report temporal semantic operations. The explain text provides the type of qualifier applied on the temporal tables being operated upon. It reports whether the query is current, sequenced, or nonsequenced.

Here is an example of the EXPLAIN report for a current query on a row-partitioned bitemporal table:

EXPLAIN SELECT * FROM Policy;

Result:

Explanation
-----------------------------------------------------------------------
  1) First, we lock DBASE.Policy for read on a reserved RowHash
     in all partitions to prevent global deadlock for DBASE.Policy.
  2) Next, we lock DBASE.Policy for read.
  3) We do an all-AMPs RETRIEVE step from a single partition of
     DBASE.Policy  (with temporal qualifier as "CURRENT 
 VALIDTIME AND CURRENT TRANSACTIONTIME") with a condition of ( 
 "((BEGIN(DBASE.Policy.Validity ))<= DATE '2010-02-18') 
 AND (((END(DBASE.Policy.Policy_Duration ))= TIMESTAMP 
 '9999-12-31 23:59:59.999999+00:00') AND 
 ((END(DBASE.Policy.Validity ))> DATE '2010-02-18'))") 
     into Spool 1 (group_amps), which is built locally on the AMPs.
     The size of Spool 1 is estimated with no confidence to be 1 row (
     85 bytes).  The estimated time for this step is 0.03 seconds.
  4) Finally, we send out an END TRANSACTION step to all AMPs involved
     in processing the request.
  -> The contents of Spool 1 are sent back to the user as the result of
     statement 1.  The total estimated time is 0.03 seconds.