Explain Plan Output

[mkumarnk]

Hi,

Please explain what is the Rows,Bytes & Cost
in the out put of EXPLAIN PLAN utility.

Regards
Manoj

[sreddy]

Rows

Number of rows accessed. This comes from the CARDINALITY column of the plan table. If appropriate, the number is converted to K (thousands), M (millions), or G (1000 millions, or billions).

Bytes

Number of bytes accessed. This is the value of the BYTES column of the plan table. If appropriate, the number is displayed in Kilobytes, Megabytes, or Gigabytes.

Cost

This is the value of the COST column of the plan table. If appropriate, the number is displayed in K (thousands), M (millions), or G (1000 millions, or billions). This column is not applicable to rule-based optimization

[mkumarnk]

Hi ,

Thanks reddy !!

While tuning the query approach should be to make less COST etc, eventhough the quey is using index ?

Regards
Manoj

[sreddy]

Initially I was inteneded to post this link for you and thought again, shooting the right answer for question... This might be the link for you to start with.
http://otn.oracle.com/docs/products/...13_exp.htm#838

Never ending topic its going to be if we start on the optimizer behaviour... different from version to version,patch to patch and specific to QUERY... I would advise you to spend some time on this topic.