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Chapter 5: Caches and Copies > Working Data Sets
Working Data Sets
So we’ve reached an important unit of memory, a collection of buffers that underpins the physical I/O behavior in Oracle. I emphasize the word physical because the mechanisms for finding and visiting buffered data (i.e., the so-called “logical” I/O) introduce a whole new pattern that cuts right across the buffer pools and working data sets . . . but we’ll come to that in a while.
Note In all the discussion to date, I have been ignoring the options for direct path reads and writes—I/O that goes to and from private process memory rather than the shared memory area. Actions that take place in private are not particularly complex, although they may cause various overheads, such as reads and block cleanout, to take place repeatedly. It’s public activity, where there’s a risk of conflict, that leads to complicated implementation details.
