# I/O Isn’t the RDBMS Bottleneck - It’s CPU

- ## Search Algorithms are Based on Disk Addresses

  - Multiple look-ups before you get to a memory pointer

- ## Data is Frequently Copied

  - Buffers must be available to be used by other pages

- ## Tables and Indices are Turned Into Random Pages

  - Serial table scans require a separate lookup sequence for each page
  - An index search invokes several page look-ups, then a data page search

- ## Optimization is Biased Toward I/O-Avoidance

  - No attention to instruction path length to perform memory operations
  - Optimizer must assume a page is on disk - it’s usually not

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