DELETE文でのEXPLAINリクエスト修飾子 - Advanced SQL Engine - Teradata Database

Teradata Vantage™ - SQLデータ操作言語

Product
Advanced SQL Engine
Teradata Database
Release Number
17.10
Published
2021年7月
Language
日本語
Last Update
2021-09-23
dita:mapPath
ja-JP/vjt1596846980081.ditamap
dita:ditavalPath
ja-JP/wrg1590696035526.ditaval
dita:id
B035-1146
Product Category
Software
Teradata Vantage

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.