Table scan cost %

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Table scan cost %

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Gail Shaw SSC Guru Points: 1004514 More actions · Answer 1

The cost % is the optimiser's estimate of how expensive an operation is relative to the rest of the query. If you have a table scan of a very small table and another operation (index seek or scan) on a very large table, it's quite normal that the table scan comes out with a low percentage.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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SQL ORACLE One Orange Chip Points: 27807 More actions · Answer 2

Cost for indexed table is unnecessarily less than table scan if indexes are not created correctly.