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Index range scan vs full table access [message #130577] Mon, 01 August 2005 04:45 Go to next message
Messages: 5
Registered: March 2005
Junior Member

I have a query written for a table which has a composite primary key. Primary key - (col1,col2,col3)
The query uses a single table and three conditions in the where clause such as
col1 = abc
col2 = xyz
col4 = pqr(some column in the table, not part of composite key)

Now when we generate an explain plan for this query it uses Index Range scan on the table.
But the explain plan generated at the client's place shows full table access for the same query.

How do I justify this and wat's more efficient index range scan or Full table access in this case. what might be the reason for this different explain plans.

Thanks & regrads,
Nitesh Rana.
Re: Index range scan vs full table access [message #130597 is a reply to message #130577] Mon, 01 August 2005 07:08 Go to previous message
Mahesh Rajendran
Messages: 10707
Registered: March 2002
Location: oracleDocoVille
Senior Member
Account Moderator
depends on many factors.
obviously, the query that runs faster is better.
FTS is usefull when your query scans more/all records. So instead of a sequential read, a scattered read is better.
Are two databases involved here?
make sure you have latest statistics collected and data is same in both databases.

[Updated on: Mon, 01 August 2005 07:09]

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