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Index/Table Space scan

 
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edkir98
Beginner


Joined: 27 Aug 2007
Posts: 102
Topics: 42
Location: Chennai
PostPosted: Tue May 26, 2009 4:45 am    Post subject: Index/Table Space scan Reply with quote
I have a query

Code:
SELECT IXCOL1,
           IXCOL2,
            NONIXCOL3
   FROM TABLE1
  WHERE IXCOL3 = :VALUE

TABLE1 has 3 indices IXCOL1/2/3 and NONIXCOL3 is a non-indexed column.

Now when the above query is executed the explain information shows that tablespace scan is used. When i remove NONIXCOL3 from this SELECT list like
Code:
SELECT IXCOL1,
           IXCOL2
   FROM TABLE1
  WHERE IXCOL3 = :VALUE
then it goes into index scan.

Will adding a non-index column in the select statement affect the nature of the scan?
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kolusu
Site Admin
Site Admin


Joined: 26 Nov 2002
Posts: 12380
Topics: 75
Location: San Jose
PostPosted: Tue May 26, 2009 9:12 am    Post subject: Reply with quote
edkir98,

Read this for a better understanding of DB2 Access paths

http://www.ibm.com/developerworks/db2/library/techarticle/0301mullins/0301mullins.html

Kolusu
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