Monitoring Disk Utilization - Teradata Database

Mistake

Solution

A user did not define a PI. The system uses the first column of the table as the default P1.

Define a PI with good data distribution.

A user used a null as PI for the target table in a left outer join.

Perform any of the following:

A user performed a join on column with poor data distribution. For example, the user entered:

SELECT A.colname, B.x, B.y
FROM A, B
WHERE A.colname =
	B.colname;

SELECT colname, count(*) 
FROM T 
	HAVING count(*) > 1000
	GROUP BY 1 ORDER BY 1 Desc;

The following displays:

colname   count(*)
codeXYZ   720,000
codeABC     1,200