External Sorting

约 80 个字

External Merge Sort

• N: Total number of records

• M: Number of records can be held in memory

• k: k-way merge

  use a \(k\) size heap

  require \(2k\) external memory

• Number of passes

  \(1 + log_k(N/M)\) , 1 for initial partition and sorting

Poly-phase Merge

Use \(k+1\) external memory.

Initial partition should be to consecutive Fibonacci number. So it can bouncing.

Parallel Merge

Computation & Memory access overlap!

\(2k\) input buffer and \(2\) output buffer

Replacement Selection

Minimize Merge Time