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Terms in Execution plan & Optimization Trace

原创 Linux操作系统 作者:staciy 时间:2011-04-13 21:11:31 0 删除 编辑

Cost:   the value of this column does not have any particular unit of measurement; It is merely a weighted value used to compute costs of execution plans.

Card:  estimated by the cost-based approach of the number of rows accessed by the operation.

Bytes: Estimated by the cost-based approach of the number of bytes accessed by the operation.

above values are not valueable to be referred or compared if they are generated by issuing different SQLs.

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