python system_error ai_generated partial

pytest.xdist.NoWorkerIdle: No idle worker available for test scheduling

ID: python/pytest-xdist-no-worker-idle

Also available as: JSON · Markdown · 中文
80%Fix Rate
80%Confidence
0Evidence
2024-11-01First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
3.9 active — — —
3.10 active — — —

Root Cause

All worker processes are busy with long-running tests, and no worker becomes free within the timeout period.

generic

中文

所有工作进程都在处理长时间运行的测试，并且在超时时间内没有工作节点空闲。

Workarounds

  1. 80% success Reduce the number of workers to match the number of available CPU cores. 
    pytest -n 4 (where 4 is the number of cores)
  2. 85% success Run long-running tests sequentially by marking them with @pytest.mark.slow and using -m 'not slow'. 
    pytest -m 'not slow' -n auto; then run slow tests separately with -n 1

Dead Ends

Common approaches that don't work:

  1. Increasing the number of workers to speed up tests 60% fail

    If tests are long, more workers may not help if the bottleneck is I/O or CPU.

  2. Setting a global timeout for all tests 70% fail

    Timeout may abort tests prematurely without addressing the scheduling issue.