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Rohit Umarjikar
Global Moderator
Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA
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Suppose I have a below query,
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Select emp_id,Dep_id,Name
from tableA
where
Dep_id=20
with ur; |
Now on tableA, the indexing sequence is in below format,
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Index info:
TableA.INDX001
emp_id
Dep_id |
So in this case would the above index will be considered or it will just ignore and do a table space scan as because of Dep_id is at second position in the index creation??
Thanks,
Rohit |
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dbzTHEdinosauer
Global Moderator
Joined: 20 Oct 2006
Posts: 6966
Location: porcelain throne
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| why don't you look at the EXPLAIN output and tell us the answer to your question? |
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GuyC
Senior Member
Joined: 11 Aug 2009
Posts: 1281
Location: Belgium
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| It depends on DB2 version, cardinality of emp_id,dep_id, number of pages,clusterratio of the index,... but most likely DB2 will choose a tablescan. |
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Rohit Umarjikar
Global Moderator
Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA
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I am trying doing that, but not finding such existing queries. but if any one is already knowing this then would save my time. 
Aslo current version is V9.1 |
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dick scherrer
Moderator Emeritus
Joined: 23 Nov 2006
Posts: 19244
Location: Inside the Matrix
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Hello,
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| I am trying doing that, but not finding such existing queries. |
You should run the Explain on YOUR query - not some existing query.
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| but if any one is already knowing this then would save my time. |
The advice you've been given is probably the best you will get with the limited info we have available.
And keep in mind that we are not here to save your time, but to help people with how/why questions and help solve problems. What you are working on Should take your time . . . |
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Rohit Umarjikar
Global Moderator
Joined: 21 Sep 2010
Posts: 3051
Location: NYC,USA
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Yes Dick, noted.
I will update you all with the explain result. |
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