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https://issues.apache.org/jira/browse/SOLR-8849?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hoss Man updated SOLR-8849:
---------------------------
    Attachment: SOLR-8849.patch

proposed patch.

in addition to cleaning up the random usage, this also refactors the 
non-loop/sleep portions of the monkeyThread into a new {{public void 
causeSomeChaos()}} method.

this way, it's possible to write a (single threaded) test with 100% 
reproducible chaos w/o needing to write your own random decision making about 
what chaos methods to call.

> ChaosMonkey should cuase chaos in a more reproducible manner
> ------------------------------------------------------------
>
>                 Key: SOLR-8849
>                 URL: https://issues.apache.org/jira/browse/SOLR-8849
>             Project: Solr
>          Issue Type: Test
>            Reporter: Hoss Man
>            Assignee: Hoss Man
>         Attachments: SOLR-8849.patch
>
>
> 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()}} ...
> {code}
>       public void run() {
>         while (!stop) {
>           try {
>     
>             Random random = LuceneTestCase.random();
>             // ... lots of stuff using random, or calling methods that use 
> LuceneTestCase.random() directly
> {code}
> 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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