{"record":{"id":"0b76dc11b6a92868","repo":"apache/seatunnel","slug":"the-update-before-event-at-for-table-was-not-fol","errorCode":null,"errorMessage":"The update before event at  for table  was not followed by after event.","messagePattern":"The update before event at  for table  was not followed by after event\\.","errorType":"exception","errorClass":"java.lang.IllegalStateException","httpStatus":null,"severity":"error","filePath":"seatunnel-connectors-v2/connector-cdc/connector-cdc-db2/src/main/java/org/apache/seatunnel/connectors/seatunnel/cdc/db2/source/reader/fetch/transactionlog/Db2TransactionLogFetchTask.java","lineNumber":330,"sourceCode":"                if (!schemaChangeCheckpoints.isEmpty()\n                        && tableWithSmallestLsn\n                                        .getChangePosition()\n                                        .getCommitLsn()\n                                        .compareTo(schemaChangeCheckpoints.peek().getStopLsn())\n                                >= 0) {\n                    migrateTable(partition, offsetContext, schemaChangeCheckpoints);\n                }\n\n                TableId tableId = tableWithSmallestLsn.getChangeTable().getSourceTableId();\n                int operation = tableWithSmallestLsn.getOperation();\n                Object[] data = tableWithSmallestLsn.getData();\n\n                int eventCount = 1;\n                if (operation == Db2ChangeRecordEmitter.OP_UPDATE_BEFORE) {\n                    if (!tableWithSmallestLsn.next()\n                            || tableWithSmallestLsn.getOperation()\n                                    != Db2ChangeRecordEmitter.OP_UPDATE_AFTER) {\n                        throw new IllegalStateException(\n                                \"The update before event at \"\n                                        + tableWithSmallestLsn.getChangePosition()\n                                        + \" for table \"\n                                        + tableId\n                                        + \" was not followed by after event.\");\n                    }\n                    eventCount = 2;\n                }\n                Object[] dataNext =\n                        operation == Db2ChangeRecordEmitter.OP_UPDATE_BEFORE\n                                ? tableWithSmallestLsn.getData()\n                                : null;\n\n                TxLogPosition currentPosition = tableWithSmallestLsn.getChangePosition();\n                offsetContext.setChangePosition(currentPosition, eventCount);\n                offsetContext.event(\n                        tableId, metadataConnection.timestampOfLsn(currentPosition.getCommitLsn()));\n","sourceCodeStart":312,"sourceCodeEnd":348,"githubUrl":"https://github.com/apache/seatunnel/blob/cf67b549a7a6c35fa0beb12d83c62892427ea919/seatunnel-connectors-v2/connector-cdc/connector-cdc-db2/src/main/java/org/apache/seatunnel/connectors/seatunnel/cdc/db2/source/reader/fetch/transactionlog/Db2TransactionLogFetchTask.java#L312-L348","documentation":"While merging DB2 change-table result sets in LSN order, an UPDATE_BEFORE event must be immediately followed by its matching UPDATE_AFTER event. If the next row is missing or is not an UPDATE_AFTER, the merged stream is corrupt and the task throws this IllegalStateException (the message interpolates change position and table id, which may render with gaps).","triggerScenarios":"readChangeTableResultSets encounters a change-table row with operation OP_UPDATE_BEFORE whose successor row is absent or has a different operation — e.g. missing change-table rows, expired change-table retention deleting one half of the pair, or concurrent modification during reads.","commonSituations":"Change-data-capture retention window too small so old rows get purged mid-read; capture instance re-created while streaming; DB2 CDC (SQL Server-style change tables) inconsistency; very high update volume during startup.","solutions":["Increase DB2 change-table retention so both halves of update pairs survive the read","Verify the capture instance is intact and restart the streaming task from a clean checkpoint","Check for jobs purging change tables concurrently with the connector's reads","Retry from the last checkpoint after confirming change-table consistency"],"exampleFix":null,"handlingStrategy":"retry","validationCode":"// ensure change-table retention exceeds expected streaming duration\n-- check DB2 CDC retention settings before long jobs","typeGuard":null,"tryCatchPattern":"try { runPipeline(); } catch (IllegalStateException e) { if (e.getMessage().contains(\"was not followed by after event\")) { verifyChangeTables(); restartFromCheckpoint(); } }","preventionTips":["Set change-table retention longer than the longest possible outage/replay","Do not purge change tables while the connector streams","Avoid re-creating capture instances mid-job"],"tags":["db2","cdc","streaming","change-log","invariant"],"backgroundTag":"internal-invariant-violation","analyzedSha":"cf67b549a7a6c35fa0beb12d83c62892427ea919","analyzedAt":"2026-09-10T21:44:55.265Z","contentChangedAt":"2026-09-10T21:44:55.265Z","schemaVersion":2},"datasetVersion":"2026-09-14T11:17:12.474Z"}