Solved: SQL Cache - Disk reads larger than buffer gets??

peter_strauss · ‎2007 Oct 25

Hello,

On an Oracle 10g test system, from ST04 -> Detailed analysis -> SQL request

I'm getting what seems to be a strange result for one statement:

Disk reads: 799,713

Buffer gets: 553.377

I thought that for each disk read, the block was read into the data buffer and then read from there.

This means that 'Disk reads' greater than 'Buffer gets' should be impossible.

Is what I'm seeing in my SQL cursor cache a bug or can someone suggest a scenario where disk reads could be greater than buffer gets?

Kind regards,

Peter

Former Member · ‎2007 Oct 25

Hello Peter,

also the hash join in the execution plan can be the reason for the direct path accesses.

Regards

Martin

SQL Cache - Disk reads larger than buffer gets??