14.4. Automatic Memory Management

Oracle performance (and, for that matter, computer performance in general) can be summed up in two basic tenets:

  • Memory is fast.

  • Disk is slow.

In fact, accessing data from memory tends to be approximately 10,000 times faster than accessing data from disk. So why is disk usage so prevalent if it is so slow? This is because of a couple of other basic tenets:

  • Memory is expensive.

  • Disk is cheap.

The terms "expensive" and "cheap" carry a deeper connotation than simply the purchase price. They also refer to the availability of the item. In fact, it might be more accurate to say that memory is scarce, while disk is plentiful.

For example, consider Oscar, the avid fisherman. He lives an hour away from the nearest lake, ...

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