{"record":{"id":"d280a3d2a80a6c03","repo":"apache/flink","slug":"could-not-write-bytes-since-the-buffer-is-full","errorCode":null,"errorMessage":"Could not write {} bytes since the buffer is full.","messagePattern":"Could not write (.+?) bytes since the buffer is full\\.","errorType":"exception","errorClass":"IOException","httpStatus":null,"severity":"error","filePath":"flink-core/src/main/java/org/apache/flink/types/Record.java","lineNumber":1843,"sourceCode":"        @SuppressWarnings(\"restriction\")\n        private static final long BASE_OFFSET = UNSAFE.arrayBaseOffset(byte[].class);\n\n        private static final boolean LITTLE_ENDIAN =\n                (MemoryUtils.NATIVE_BYTE_ORDER == ByteOrder.LITTLE_ENDIAN);\n\n        @Override\n        public void skipBytesToWrite(int numBytes) throws IOException {\n            int skippedBytes = skipBytes(numBytes);\n\n            if (skippedBytes != numBytes) {\n                throw new EOFException(\"Could not skip \" + numBytes + \" bytes.\");\n            }\n        }\n\n        @Override\n        public void write(DataInputView source, int numBytes) throws IOException {\n            if (numBytes > this.end - this.position) {\n                throw new IOException(\n                        \"Could not write \" + numBytes + \" bytes since the buffer is full.\");\n            }\n\n            source.readFully(this.memory, this.position, numBytes);\n            this.position += numBytes;\n        }\n    }\n}\n","sourceCodeStart":1825,"sourceCodeEnd":1852,"githubUrl":"https://github.com/apache/flink/blob/2f3c205e9266cb30240eb7f4fdab15cad629a70f/flink-core/src/main/java/org/apache/flink/types/Record.java#L1825-L1852","documentation":"Thrown by the DataOutputView-style write(DataInputView source, int numBytes) on Record's output view, used to bulk-copy bytes from a source view into the record's memory. Unlike other write methods it does NOT resize: it requires numBytes <= this.end - this.position (remaining space in the fixed-size target segment) and otherwise throws an IOException that the buffer is full.","triggerScenarios":"Calling write(source, numBytes) with numBytes greater than the space left between position and end in the target buffer; common when copying a large field into a nearly full segment or when end was set to a fixed capacity (not the array length).","commonSituations":"Splicing records between bounded memory segments; capacity computed from a stale position after a failed/partial copy; forgetting that this helper is capacity-bounded while write(byte[]) auto-resizes.","solutions":["Ensure end - position >= numBytes before the call, or grow/reallocate the target segment first","Use write(byte[]) / writeUTF paths (which resize) instead of write(DataInputView, int) when the size is not guaranteed","Reset the target view's position/end appropriately when reusing buffers between records"],"exampleFix":"// before\ntarget.write(source, numBytes); // numBytes > target remaining\n\n// after\nif (targetEnd - targetPos < numBytes) {\n    growTarget(numBytes);\n}\ntarget.write(source, numBytes);","handlingStrategy":"validation","validationCode":"if (numBytes > end - position) {\n    throw new IllegalStateException(\"target segment too small: need \" + numBytes + \", have \" + (end - position));\n}\nview.write(source, numBytes);","typeGuard":null,"tryCatchPattern":"catch (IOException e) { if (e.getMessage().contains(\"buffer is full\")) { growSegment(); view.write(source, numBytes); } else throw e; }","preventionTips":["Remember write(DataInputView,int) never resizes","Track remaining capacity alongside position","Reset position/end when reusing segments"],"tags":["flink","serialization","record","buffer-full","capacity"],"backgroundTag":null,"analyzedSha":"2f3c205e9266cb30240eb7f4fdab15cad629a70f","analyzedAt":"2026-08-14T08:48:24.518Z","schemaVersion":2},"datasetVersion":"2026-08-14T10:17:34.591Z"}