16.20 - DELETE文でのEXPLAINリクエスト修飾子 - Teradata Database - Teradata Vantage NewSQL Engine

Teradata Vantage™ SQLデータ操作言語

Product
Teradata Database
Teradata Vantage NewSQL Engine
Release Number
16.20
Release Date
2019年3月
Content Type
プログラミング リファレンス
Publication ID
B035-1146-162K-JPN
Language
日本語 (日本)

このEXPLAINリクエスト修飾子は、DELETE文を実行するための手順およびDELETEおよびSELECTの制約の適用結果を示します。

       EXPLAIN DELETE FROM rls_tbl WHERE col1=2;

システムは、このEXPLAINテキストを返します。

 *** Help information returned. 10 rows.
 *** Total elapsed time was 1 second.
Explanation
----------------------------------------------------------------------
  1) First, we do a single-AMP DELETE from RS.rls_tbl by way of the
     primary index "RS.rls_tbl.col1 = 2" with a residual condition of (
     "((SYSLIB.DELETELEVEL (RS.rls_tbl.levels ))= 'T') AND
     (((SYSLIB.SELECTLEVEL (2, RS.rls_tbl.levels ))= 'T') AND
     (((SYSLIB.DELETECATEGORIES (RS.rls_tbl.categories ))= 'T') AND
     ((SYSLIB.SELECTCATEGORIES ('90000000'XB, RS.rls_tbl.categories ))=
     'T')))").  The size is estimated with no confidence to be 2 rows.
     The estimated time for this step is 0.01 seconds.
  -> No rows are returned to the user as the result of statement 1.
     The total estimated time is 0.01 seconds.