When to rewrite away deletes

Worked examples, recomputed

Every number the mechanisms quote for this relationship is recomputed from it, so none of them disagrees with it.

• d = 0.2, 50 reads → 10 > 1: rewrite
• 3 reads → 0.6 < 1: leave it

Where it appears

Each mechanism states it in its own names. The general symbol each name stands for is shown with it.

• Table & Storage Maintenance

  Who pays for the gap between the order data arrives in and the order it is read in: the writer, every reader, or a background job, and what is the break-even?

  $$d\times \text{expected future reads}>1$$

  Read it in place →