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  1. Solr
  2. SOLR-8849

ChaosMonkey should cuase chaos in a more reproducible manner

    Details

    • Type: Test
    • Status: Resolved
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: 6.0
    • Component/s: None
    • Labels:
      None

      Description

      Looking into the ChaosMonkey code a bit, and it seems like this class – particularly the way monkeyThread is defined – uses randomness in a way that makes it extremely unlikely that it will ever create reproducible failures.

      Obviously in any test where there are multiple concurrent threads, timing issues might prevent test reproducibility – but in this case, even the sequence of "chaos" actions the monkeyThread takes won't be reproducible if anyother concurrent test thread accesses LuceneTestCase.random() ...

            public void run() {
              while (!stop) {
                try {
          
                  Random random = LuceneTestCase.random();
                  // ... lots of stuff using random, or calling methods that use LuceneTestCase.random() directly
      

      It seems like it would be a lot better if ChaosMonkey's constructor created it's own private Random chaosRand using LuceneTestCase.random() as a seed, and then used chaosRand to make all random choices in it's methods.

      That way at least the sequence of chaotic operations made by ChaosMonkey would be consistent for a given test seed, even if the exact timing/interleaving of those operations relative to other operations by other threads couldn't be garunteed.

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            • Assignee:
              hossman Hoss Man
              Reporter:
              hossman Hoss Man
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              • Created:
                Updated:
                Resolved: