Database I/O occurs when the database engine reads and writes blocks containing records to and from disk into memory. To minimize database disk I/O, the database engine tries to keep a block in memory after it reads the block the first time. The next time the engine needs that block, it can access it from memory rather than reading it from disk.

To eliminate database I/O bottlenecks, you can:

  • Increase the number of database buffers
  • Change the number and structure of database storage areas
  • Use private read-only buffers
  • Use asynchronous page writers (APWs)