B+ Trees in Practice

• Typical order: 100. Typical fill-factor: 67%.

  • average fanout = 133

• Typical capacities:

  • Height 4: 1334 = 312,900,700 records
  • Height 3: 1333 = 2,352,637 records

• Can often hold top levels in buffer pool:

  • Level 1 = 1 page = 8 Kbytes
  • Level 2 = 133 pages = 1 Mbyte
  • Level 3 = 17,689 pages = 133 MBytes

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