[IMPROVED] Publish permissions cache pruning#6674
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neilalexander merged 1 commit intomainfrom Mar 14, 2025
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The test `TestLeafNodePubAllowedPruning` would sometimes report (after all go routines calling c.pubAllowed() being done) that the cache size was greater than the max allowed (128). @MauriceVanVeen did fix the test with a correct explanation of why this test flapped, but I think we can improve a tiny bit the code so that the cache is much likely to be pruned enough. In this PR, I make `prunePubPermsCache()` attempts up to 5 times to prune enough the cache, locking/releasing at each attempt to improve the odds that another routine takes a shot at it. In my experiments, I am seeing only up to 2 attempts to be below the max size (and less than 10ms execution time). That being said, with artificial sleep before the release of the lock, it could take way more attempts. So for very slow machines, although I have reverted the changes to the test done in PR#6636, I did add a little protection to call one more time `c.pubAllowed()` if we first detect that we are over the limit. If we are still after that the test will fail and would need another look. Signed-off-by: Ivan Kozlovic <ivan@synadia.com>
wallyqs
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Mar 13, 2025
MauriceVanVeen
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Mar 14, 2025
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Includes the following (already cherry-picked) PRs: - #6587 - #6607 - #6612 - #6609 - #6620 - #6668 - #6674 - #6647 - #6684 - #6691 - #6697 - #6705 - #6706 - #6704 - #6714 - #6720 - #6727 - #6730 - #6726 - #6732 - #6759 - #6753 - #6685 - #6769 - #6777 - #6785 - #6786 - #6778 - #6790 - #6791 - #6798 - #6794 - #6801 Signed-off-by: Neil Twigg <neil@nats.io> Signed-off-by: Neil Twigg <neil@nats.io>
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The test
TestLeafNodePubAllowedPruningwould sometimes report (after all go routines calling c.pubAllowed() being done) that the cache size was greater than the max allowed (128).@MauriceVanVeen did fix the test with a correct explanation of why this test flapped, but I think we can improve a tiny bit the code so that the cache is much likely to be pruned enough.
In this PR, I make
prunePubPermsCache()attempts up to 5 times to prune enough the cache, locking/releasing at each attempt to improve the odds that another routine takes a shot at it.In my experiments, I am seeing only up to 2 attempts to be below the max size (and less than 10ms execution time). That being said, with artificial sleep before the release of the lock, it could take way more attempts. So for very slow machines, although I have reverted the changes to the test done in PR#6636, I did add a little protection to call one more time
c.pubAllowed()if we first detect that we are over the limit. If we are still after that the test will fail and would need another look.Signed-off-by: Ivan Kozlovic ivan@synadia.com