[CASSANDRA-18848] GCInspector "Error accessing field of java.nio.Bits" under java17 - ASF JIRA

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Details

Type: Bug
Status: Resolved
Priority: Low
Resolution: Fixed
Fix Version/s: 5.0-alpha2, 5.0, 5.1
Component/s: Observability/Metrics
Labels:
None

Epic Link:
Support Java 17
Severity:
Low
Complexity:
Normal
Discovered By:
User Report
Since Version:

5.0-alpha1
Source Control Link:

https://github.com/apache/cassandra/commit/2b23fc58aa86a1cd0c98f97ddcf43305869d041e https://github.com/apache/cassandra/commit/89065ffa2189861c0437fd1f1a5748df006e8907
Test and Documentation Plan:

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5.0 Patch PR: https://github.com/apache/cassandra/pull/2683

5.0 JDK17 green CI run: https://app.circleci.com/pipelines/github/ekaterinadimitrova2/cassandra/2512/workflows/450638d5-873e-4257-824b-0db189236615

Also, tested locally and verified the debug log, no more exceptions are thrown. I believe we can safely propagate the patch to trunk and do only local check, saving on resources for full CI run.

I also used the opportunity to clean a few lines of dead code JDK8 related. TOTAL_CAPACITY had a different name in JDK8 so we were checking for that one in case we are on JDK8, but we dropped it already for 5.0+.

Show
5.0 Patch PR: https://github.com/apache/cassandra/pull/2683 5.0 JDK17 green CI run: https://app.circleci.com/pipelines/github/ekaterinadimitrova2/cassandra/2512/workflows/450638d5-873e-4257-824b-0db189236615 Also, tested locally and verified the debug log, no more exceptions are thrown. I believe we can safely propagate the patch to trunk and do only local check, saving on resources for full CI run. I also used the opportunity to clean a few lines of dead code JDK8 related. TOTAL_CAPACITY had a different name in JDK8 so we were checking for that one in case we are on JDK8, but we dropped it already for 5.0+.

Description

Running under java17, GCInspector throws the following exception:

DEBUG [main] 2023-09-13 09:35:28,031 GCInspector.java:85 - Error accessing field of java.nio.Bits
java.lang.reflect.InaccessibleObjectException: Unable to make field private static final java.util.concurrent.atomic.AtomicLong java.nio.Bits.TOTAL_CAPACITY accessible: module java.base does not "opens java.nio" to unnamed module @503d687a
        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:354)
        at java.base/java.lang.reflect.AccessibleObject.checkCanSetAccessible(AccessibleObject.java:297)
        at java.base/java.lang.reflect.Field.checkCanSetAccessible(Field.java:178)
        at java.base/java.lang.reflect.Field.setAccessible(Field.java:172)
        at org.apache.cassandra.service.GCInspector.<clinit>(GCInspector.java:80)
        at org.apache.cassandra.service.CassandraDaemon.setup(CassandraDaemon.java:328)
        at org.apache.cassandra.service.CassandraDaemon.activate(CassandraDaemon.java:729)
        at org.apache.cassandra.service.CassandraDaemon.main(CassandraDaemon.java:853)
INFO  [main] 2023-09-13 09:35:28,039 PaxosUncommittedTracker.java:236 - enabling PaxosUncommittedTracker

This is because GCInspector uses reflection to read the TOTAL_CAPACITY from java.nio.Bits. Access was restricted somewhere between 11 and 17.

Note: this is a rather harmless error, as we only look at Bits.totalCapacity for metrics collection on how much direct memory is being used by {{ByteBuffer}}s. If we fail to read the field, we simply return -1 for the metric value.

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Assignee:: Ekaterina Dimitrova

Reporter:: Ekaterina Dimitrova

Authors:: Ekaterina Dimitrova

Reviewers:: Michael Semb Wever, Stefan Miklosovic

Votes:: 0 Vote for this issue

Watchers:: 5 Start watching this issue

Dates

Created:: 13/Sep/23 13:47

Updated:: 01/Nov/23 08:54

Resolved:: 14/Sep/23 17:33