{"record":{"id":"5271357614ec40b6","repo":"apache/iceberg","slug":"failed-to-fetch-table-changes-for-527135","errorCode":null,"errorMessage":"Failed to fetch table changes for {}","messagePattern":"Failed to fetch table changes for (.+?)","errorType":"console","errorClass":null,"httpStatus":null,"severity":"warning","filePath":"flink/v2.2/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/MonitorSource.java","lineNumber":147,"sourceCode":"          if (snapshot != null) {\n            if (!DataOperations.REPLACE.equals(snapshot.operation())) {\n              LOG.debug(\"Reading snapshot {}\", snapshot.snapshotId());\n              event.merge(new TableChange(snapshot, table));\n            } else {\n              LOG.debug(\"Skipping replace snapshot {}\", snapshot.snapshotId());\n            }\n\n            checking = snapshot.parentId();\n          } else {\n            // If the last snapshot has been removed from the history\n            checking = null;\n          }\n        }\n\n        lastSnapshotId = current;\n        return event;\n      } catch (Exception e) {\n        LOG.warn(\"Failed to fetch table changes for {}\", table, e);\n        return TableChange.empty();\n      }\n    }\n\n    @Override\n    public String toString() {\n      return MoreObjects.toStringHelper(this)\n          .add(\"lastSnapshotId\", lastSnapshotId)\n          .add(\"maxReadBack\", maxReadBack)\n          .add(\"table\", table)\n          .toString();\n    }\n  }\n\n  private static final class TableChangeIteratorSerializer\n      implements SimpleVersionedSerializer<Iterator<TableChange>> {\n\n    private static final int CURRENT_VERSION = 1;","sourceCodeStart":129,"sourceCodeEnd":165,"githubUrl":"https://github.com/apache/iceberg/blob/86d9c8fc543e7c56c9f624eb725f76c9baff9570/flink/v2.2/flink/src/main/java/org/apache/iceberg/flink/maintenance/operator/MonitorSource.java#L129-L165","documentation":"MonitorSource's change reader iterator fetches new table changes (snapshots since lastSnapshotId) so downstream tasks can react to rewrites/expirations. If reading the changes throws, it logs a warning with the table name and returns TableChange.empty(), meaning the trigger cycle sees no change and maintenance proceeds based on scheduled triggers rather than table activity. The error is swallowed by design to keep the monitoring source alive.","triggerScenarios":"Raised in the iterator's next() when refreshing the table or building a SnapshotIterable/change reader between lastSnapshotId and the current snapshot throws — expired snapshots, catalog access errors, or corrupted snapshot metadata.","commonSituations":"Snapshot expiration by another job removing snapshots the reader expected; REST/Hive catalog auth token expiry; table dropped or renamed while the monitor runs; network partition to the catalog.","solutions":["Check the nested exception for catalog access problems and fix connectivity/credentials","Coordinate expiration jobs with the maintenance monitor so it does not read removed snapshots","Verify the table still exists and the maintenance action's table identifier is correct","No code fix needed for transient errors — the next poll re-fetches changes from the last committed snapshot id"],"exampleFix":null,"handlingStrategy":"fallback","validationCode":null,"typeGuard":null,"tryCatchPattern":"// Library returns TableChange.empty() on failure; monitor logs:\n// grep 'Failed to fetch table changes for' taskmanager.log","preventionTips":["Coordinate snapshot expiration with the monitor so referenced snapshots survive","Keep catalog credentials refreshed for long-running maintenance jobs","Confirm the monitored table exists and the identifier is correct"],"tags":["flink","monitoring","snapshot","table-change"],"backgroundTag":"snapshot-read-failed","analyzedSha":"86d9c8fc543e7c56c9f624eb725f76c9baff9570","analyzedAt":"2026-09-12T00:46:39.097Z","contentChangedAt":"2026-09-12T00:46:39.097Z","schemaVersion":2},"datasetVersion":"2026-09-14T11:17:12.474Z"}