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Message Posted: Wed, 22 Jun 2011 @ 14:17:44 GMT
I have a real head-scratcher here:
I have 2 identical, 1-node Teradata systems:
and 2 identical tables, one on each system.
However, when I Explain a simple DELETE statement on system 1, it adds an extra line to the explain plan compared to system 2. The line is: "We spoil the parser's dictionary cache for the table."
Now, I know that flushing parser's cache can significantly slow-down my deletes. Especially when there are thousands of them, line-per-line. I am aware of the fact that a delete in batch mode would be much more efficient here. However, I am still curious about a reason for this behaviour.
If someone can enlighten me, I'd be grateful.
DEL FROM DB.TableName WHERE COLUMN2 = 2
Explain System 1:
Explain System 2:
The DDL is as follows:
CREATE SET TABLE DB.TABLENAME ,NO FALLBACK , NO BEFORE JOURNAL, NO AFTER JOURNAL, CHECKSUM = DEFAULT ( COLUMN1 INTEGER NOT NULL, COLUMN2 DECIMAL(8,0), COLUMN3 BYTEINT, COLUMN4 VARCHAR(255) CHARACTER SET LATIN NOT CASESPECIFIC, COLUMN5 SMALLINT, COLUMN6 SMALLINT, COLUMN7 TIMESTAMP(0) NOT NULL DEFAULT CURRENT_TIMESTAMP(0)) PRIMARY INDEX ( COLUMN1, COLUMN2 );
Thanks a lot.
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