if we take 2 tables(like emp and dept), we use join stage and how to improve t

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if we take 2 tables(like emp and dept), we use join stage and
how to improve the performance?

Question Posted / prasad

5 Answers
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if we take 2 tables(like emp and dept), we use join stage and how to improve the performance? ..

Answer / kiran

when ever join 2 tables based on key columns if the key
column is numeric ,set modulus,if the key column is non
numeric set hash partition technique.and compare to look up
join give better performance coz join has sort operation
by default.

Is This Answer Correct ?

11 Yes

2 No

if we take 2 tables(like emp and dept), we use join stage and how to improve the performance? ..

Answer / ashok

above answer has one mistake
i.e join doesn't has sort operation bydefault we explicitly
specify

Is This Answer Correct ?

9 Yes

3 No

if we take 2 tables(like emp and dept), we use join stage and how to improve the performance? ..

Answer / poorna chandra

Hi this is Poorna ,

We can Improve the performance on join stage by doing
pre sorting for both left and right data based on
key .Then we can Improve the performance in join stage .

Plz correct me if any mistake in thinking .

Is This Answer Correct ?

6 Yes

1 No

if we take 2 tables(like emp and dept), we use join stage and how to improve the performance? ..

Answer / rajeshchunduri

in emp and dept tables key column is deptno so it is key
based and datatype for key column is int . At this time we
change partion tech from hash to modulus.

chunduri

Is This Answer Correct ?

1 Yes

1 No

if we take 2 tables(like emp and dept), we use join stage and how to improve the performance? ..

Answer / professional

Hi,
For the above query to improve the performance based on key columns in emp and dept joins by default sort in datastage for better performance if you have already a sorted data just go for environmental variables and do the operation #APT_Not_SORTDATA option then performance increase automatically...

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0 No

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