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https://issues.apache.org/jira/browse/ZOOKEEPER-2789?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16020640#comment-16020640
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Hadoop QA commented on ZOOKEEPER-2789:
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-1 overall. GitHub Pull Request Build
+1 @author. The patch does not contain any @author tags.
+1 tests included. The patch appears to include 15 new or modified tests.
+1 javadoc. The javadoc tool did not generate any warning messages.
+1 javac. The applied patch does not increase the total number of javac
compiler warnings.
+1 findbugs. The patch does not introduce any new Findbugs (version 3.0.1)
warnings.
+1 release audit. The applied patch does not increase the total number of
release audit warnings.
-1 core tests. The patch failed core unit tests.
+1 contrib tests. The patch passed contrib unit tests.
Test results:
https://builds.apache.org/job/PreCommit-ZOOKEEPER-github-pr-build/736//testReport/
Findbugs warnings:
https://builds.apache.org/job/PreCommit-ZOOKEEPER-github-pr-build/736//artifact/trunk/build/test/findbugs/newPatchFindbugsWarnings.html
Console output:
https://builds.apache.org/job/PreCommit-ZOOKEEPER-github-pr-build/736//console
This message is automatically generated.
> Reassign `ZXID` for solving 32bit overflow problem
> --------------------------------------------------
>
> Key: ZOOKEEPER-2789
> URL: https://issues.apache.org/jira/browse/ZOOKEEPER-2789
> Project: ZooKeeper
> Issue Type: Bug
> Components: quorum
> Affects Versions: 3.5.3
> Reporter: Benedict Jin
> Fix For: 3.6.0
>
> Original Estimate: 168h
> Remaining Estimate: 168h
>
> If it is `1k/s` ops, then as long as $2^32 / (86400 * 1000) \approx 49.7$
> days ZXID will exhausted. But, if we reassign the `ZXID` into 16bit for
> `epoch` and 48bit for `counter`, then the problem will not occur until after
> $Math.min(2^16 / 365, 2^48 / (86400 * 1000 * 365)) \approx Math.min(179.6,
> 8925.5) = 179.6$ years.
> However, i thought the ZXID is `long` type, reading and writing the long type
> (and `double` type the same) in JVM, is divided into high 32bit and low 32bit
> part of the operation, and because the `ZXID` variable is not modified with
> `volatile` and is not boxed for the corresponding reference type (`Long` /
> `Double`), so it belongs to [non-atomic operation]
> (https://docs.oracle.com/javase/specs/jls/se8 /html/jls-17.html#jls-17.7).
> Thus, if the lower 32 bits of the upper 32 bits are divided into the entire
> 32 bits of the `long`, there may be a concurrent problem.
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