release-2.1: storage: don't clear lastTxnMeta on WriteIntentError to different key #32853
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Fixes cockroachdb#32582. This change removes a faulty optimization in the `contentionQueue`. The optimization removed the txnMeta associated with a contended key in the queue when it found a `WriteIntentError` from a different key. It didn't take into account that this error could be from an earlier request within the same batch, meaning that we can't make any assumptions about the state of the previously contended intent simply because we see a different `WriteIntentError`. Release note (bug fix): Fix a bug where metadata about contended keys was inadvertently ignored, allowing for a failure in txn cycle detection and transaction deadlocks in rare cases.
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bdarnell
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Dec 5, 2018
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Saw in CI of cockroachdb#32853. We were ignoring deadlock errors on txn4, but not txn5. Release note: None
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Waiting on #32864. |
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32864: storage: fix flake in TestContendedIntentChangesOnRetry r=nvanbenschoten a=nvanbenschoten Saw in CI of #32853. We were ignoring deadlock errors on txn4, but not txn5. Release note: None Co-authored-by: Nathan VanBenschoten <[email protected]>
Saw in CI of cockroachdb#32853. We were ignoring deadlock errors on txn4, but not txn5. Release note: None
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Cherry-picked #32864. Merging on green. |
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Backport 1/1 commits from #32773.
/cc @cockroachdb/release
Fixes #32582.
This change removes a faulty optimization in the
contentionQueue.The optimization removed the txnMeta associated with a contended key
in the queue when it found a
WriteIntentErrorfrom a different key.It didn't take into account that this error could be from an earlier
request within the same batch, meaning that we can't make any assumptions
about the state of the previously contended intent simply because we
see a different
WriteIntentError.Release note (bug fix): Fix a bug where metadata about contended keys
was inadvertently ignored, allowing for a failure in txn cycle detection
and transaction deadlocks in rare cases.