{"record":{"id":"a91fa51324fc8a6e","repo":"apache/flink","slug":"problem-while-truncating-file-path","errorCode":null,"errorMessage":"Problem while truncating file: ${path}","messagePattern":"Problem while truncating file: (.+?)","errorType":"exception","errorClass":"IOException","httpStatus":null,"severity":"error","filePath":"flink-filesystems/flink-hadoop-fs/src/main/java/org/apache/flink/runtime/fs/hdfs/HadoopRecoverableFsDataOutputStream.java","lineNumber":154,"sourceCode":"    //  Reflection utils for truncation\n    //    These are needed to compile against Hadoop versions before\n    //    Hadoop 2.7, which have no truncation calls for HDFS.\n    // ------------------------------------------------------------------------\n\n    private static void safelyTruncateFile(\n            final FileSystem fileSystem, final Path path, final HadoopFsRecoverable recoverable)\n            throws IOException {\n\n        ensureTruncateInitialized();\n\n        revokeLeaseByFileSystem(fileSystem, path);\n\n        // truncate back and append\n        boolean truncated;\n        try {\n            truncated = truncate(fileSystem, path, recoverable.offset());\n        } catch (Exception e) {\n            throw new IOException(\"Problem while truncating file: \" + path, e);\n        }\n\n        if (!truncated) {\n            // Truncate did not complete immediately, we must wait for\n            // the operation to complete and release the lease.\n            revokeLeaseByFileSystem(fileSystem, path);\n        }\n    }\n\n    private static void ensureTruncateInitialized() throws FlinkRuntimeException {\n        if (HadoopUtils.isMinHadoopVersion(2, 7) && truncateHandle == null) {\n            Method truncateMethod;\n            try {\n                truncateMethod = FileSystem.class.getMethod(\"truncate\", Path.class, long.class);\n            } catch (NoSuchMethodException e) {\n                throw new FlinkRuntimeException(\n                        \"Could not find a public truncate method on the Hadoop File System.\");\n            }","sourceCodeStart":136,"sourceCodeEnd":172,"githubUrl":"https://github.com/apache/flink/blob/2f3c205e9266cb30240eb7f4fdab15cad629a70f/flink-filesystems/flink-hadoop-fs/src/main/java/org/apache/flink/runtime/fs/hdfs/HadoopRecoverableFsDataOutputStream.java#L136-L172","documentation":"While preparing a resume, safelyTruncateFile invokes the reflective Hadoop truncate call and any exception it throws is wrapped in IOException('Problem while truncating file: <path>'). The nested cause carries the real Hadoop-side failure (permissions, lease, connectivity, unsupported operation).","triggerScenarios":"safelyTruncateFile -> truncate(fileSystem, path, recoverable.offset()) throwing: e.g. AccessControlException, lease not released, NameNode unreachable, or UnsupportedOperationException from a filesystem without truncate.","commonSituations":"Resuming an HDFS file sink when the temp file's lease is still held by a dead task; permissions changed between write and resume; using a Hadoop-compatible store (some S3 emulators, WebHDFS frontends) that does not implement truncate.","solutions":["Inspect the nested cause and address it: release the HDFS lease (hdfs debug recoverLease or wait for soft limit), fix permissions, restore NameNode connectivity","Verify the target filesystem actually supports truncate (real HDFS 2.7+; many Hadoop-compatible stores do not)","If the file cannot be resumed, discard it and let the sink rewrite the part from the last checkpoint"],"exampleFix":"# release a stuck lease before resume\nhdfs debug -recoverLease -path <tempFile> -resync","handlingStrategy":"try-catch","validationCode":null,"typeGuard":null,"tryCatchPattern":"try {\n    out = writer.recover(recoverable);\n} catch (IOException e) {\n    if (e.getMessage().contains(\"Problem while truncating\")) {\n        Throwable cause = e.getCause();\n        // lease: recoverLease and retry; permissions: fix and retry; unsupported: rewrite file\n    }\n}","preventionTips":["Release stale HDFS leases before resuming (hdfs debug -recoverLease)","Verify write permissions on temp directories after any security changes","Confirm the target filesystem implements truncate before relying on resume"],"tags":["hdfs","truncate","recovery","wrapper-exception"],"backgroundTag":null,"analyzedSha":"2f3c205e9266cb30240eb7f4fdab15cad629a70f","analyzedAt":"2026-08-14T08:48:24.518Z","schemaVersion":2},"datasetVersion":"2026-08-14T10:17:34.591Z"}