Skip to main content

I/O-bound

A workload whose runtime is limited by reading and writing data rather than by calculation. Adding workers to an I/O-bound job adds waiting, not throughput.

Establish the ratio of read time to compute time before concluding a workload will benefit from more workers.

Data & I/OPerformance & optimization

Related terms

  • Compute-bound: A workload whose runtime is limited by how fast calculations can be performed. Adding workers to a compute-bound job generally makes it finish sooner.
  • Columnar format: A file format that stores values grouped by column rather than by row, so a reader can fetch only the fields it needs.
  • Object storage: Storage reachable by every node in a cluster. Inputs must live here, or in workspace storage, rather than on one machine’s local disk.
  • Profiling: Measuring where a program actually spends its time, before deciding what to optimize.