{"record":{"id":"54b042d77ea9be2c","repo":"apache/cassandra","slug":"error-reading-key-s-in-segment-s-at-position-d","errorCode":null,"errorMessage":"Error reading key %s in segment %s at position %d: %s","messagePattern":"Error reading key (.+?) in segment (.+?) at position (.+?): (.+?)","errorType":"exception","errorClass":"RuntimeException","httpStatus":null,"severity":"error","filePath":"src/java/org/apache/cassandra/tools/StandaloneJournalUtil.java","lineNumber":179,"sourceCode":"                    if (metadataOnly)\n                        return;\n\n                    StaticSegment<JournalKey, Object> segment = DumpUtil.open(descriptor, JournalKey.SUPPORT);\n                    segment.forEachRecord((segment1, position, key, buffer, userVersion) -> {\n                        if (kind != null && key.type != JournalKey.Type.valueOf(kind))\n                            return;\n\n                        if (txnId != null && !TxnId.parse(txnId).equals(key.id))\n                            return;\n\n                        try (DataInputBuffer in = new DataInputBuffer(buffer, false))\n                        {\n                            Object v = key.type.serializer.deserialize(key, in, Version.V1);\n                            output.out.printf(\"%s: %s%n\", key, v);\n                        }\n                        catch (Throwable t)\n                        {\n                            throw new RuntimeException(String.format(\"Error reading key %s in segment %s at position %d: %s\",\n                                                                key, segment1, position, t.getMessage()), t);\n                        }\n                    });\n                });\n            }\n            catch (IOException e)\n            {\n                throw new RuntimeException(e);\n            }\n\n        }\n    }\n\n    @Command(name = \"dump_journal\", description = \"Dump journal\")\n    public static class DumpJournal implements Runnable\n    {\n        @Option(names = {\"-s\", \"--sstables\"}, description = \"Path to sstables\")\n        public String sstables;","sourceCodeStart":161,"sourceCodeEnd":197,"githubUrl":"https://github.com/apache/cassandra/blob/88fd0f6a0eaed8943f05ac9e8f947882b8ddc8f1/src/java/org/apache/cassandra/tools/StandaloneJournalUtil.java#L161-L197","documentation":"StandaloneJournalUtil (offline journal dump/read tool) deserializes each key from a journal segment and prints it. If deserialization of a key throws, the tool wraps the failure in a RuntimeException pinpointing the key, segment, and byte position, with the original throwable as cause — so the corrupt/unreadable entry can be located precisely.","triggerScenarios":"Reading a journal segment whose bytes at a key position cannot be deserialized with Version.V1 serializers: corrupted segment data, truncated entry, or a payload written by an incompatible version.","commonSituations":"Disk corruption or torn writes in journal segment files; reading segments copied from a node running a different Cassandra version; interrupted compaction/truncation of the journal.","solutions":["Inspect the cause in the stack trace to see the actual deserialization failure","Restore the corrupted segment from a replica/backup of the same journal","Verify the tool and data files come from compatible Cassandra versions","Isolate the bad segment file and exclude it / re-copy it before running the dump again"],"exampleFix":null,"handlingStrategy":"try-catch","validationCode":"if (!segmentFile.canRead() || segmentFile.length() == 0)\n    throw new IllegalStateException(\"Segment unreadable or empty: \" + segmentFile);","typeGuard":null,"tryCatchPattern":"try { StandaloneJournalUtil.run(...); }\ncatch (RuntimeException e) {\n    LOG.error(\"journal read failed at \" + e.getMessage(), e.getCause());\n}","preventionTips":["Use the same Cassandra version's tooling as the data files","Copy journal segments only from cleanly stopped nodes or verified snapshots","Check disk/corruption health when deserialization failures repeat"],"tags":["journal","deserialization","offline-tools","cassandra"],"backgroundTag":"deserialization-failed","analyzedSha":"88fd0f6a0eaed8943f05ac9e8f947882b8ddc8f1","analyzedAt":"2026-09-10T07:29:22.284Z","contentChangedAt":"2026-09-10T07:29:22.284Z","schemaVersion":2},"datasetVersion":"2026-09-14T16:17:12.679Z"}