Oracle Database Discussions

hi guys,

these are the definitions I have read at

[http://www.orafaq.com/wiki|http://www.orafaq.com/wiki]

PIO or Physical I/O refers to reading and writing from/to disk.
LIO or Logical I/O refers to reading and writing from/to memory (for example, from/to the SGA Buffer Cache)

Basically, from what I read, the COST is measured in PIOs.

If we had a query that returned 20 rows, and:

2 rows of the 20 were found in datablock X in Buffer cache
4 rows of the 20 were found in datablock Y in Buffer cache

2 rows of the 20 were found in datablock A on disk
2 rows of the 20 were found in datablock B on disk
2 rows of the 20 were found in datablock C on disk
2 rows of the 20 were found in datablock D on disk
6 rows of the 20 were found in datablock E on disk

then would it be correct to say that LIO is 2 and PIO is 5?

And we'd say the cost of this operation was 5. Is that correct?

thanks