Answer: Change the Copy activity setting to Binary Copy.

## Analysis of the Error and Solution The error `DelimitedTextMoreColumnsThanDefined` occurs when Azure Data Factory (ADF) attempts to process a file as delimited text (CSV/TSV) but encounters more columns than expected in the data structure. In this specific case: - **Key Observation**: The source file `0_2020_11_09_11_43_32.avro` is an **Avro file**, but ADF is incorrectly trying to process it as `Csv/Tsv Format Text`. - **Root Cause**: ADF is attempting schema validation and parsing the Avro file as if it were a delimited text file, which causes the column mismatch error. ## Evaluation of Options ### ✅ **Option A: Change the Copy activity setting to Binary Copy** - **Optimal Solution**: Binary Copy treats files as binary objects without attempting to parse or validate their content structure. - **Why It Works**: Since the requirement is simply to copy files between folders (Folder1 to Folder2), Binary Copy bypasses schema validation entirely, copying the Avro files exactly as they are. - **Best Practice**: This approach is recommended for bulk file migration scenarios where data transformation is not required, especially when dealing with binary formats like Avro, Parquet, or mixed file types. ### ❌ Option B: Lower the degree of copy parallelism - **Not Relevant**: This setting affects performance and throughput but does not address the fundamental schema parsing issue causing the error. - **Impact**: Reducing parallelism might slow down the copy operation but won't resolve the column mismatch problem. ### ❌ Option C: Add an explicit mapping - **Inappropriate for This Scenario**: Explicit mapping requires ADF to parse and understand the file structure, which is exactly what's causing the error with Avro files. - **Limitation**: Since ADF is incorrectly interpreting the Avro file as CSV/TSV, explicit mapping would still fail because the underlying parsing mechanism is wrong for the file format. ### ❌ Option D: Enable fault tolerance to skip incompatible rows - **Suboptimal Approach**: While this would allow the copy to continue by skipping problematic rows, it results in data loss. - **Not Recommended**: The error occurs because ADF is using the wrong parsing method for Avro files, not because the data itself is inherently incompatible. Skipping rows would discard valid Avro data. ## Conclusion **Binary Copy (Option A)** is the correct solution because it addresses the root cause: ADF should not attempt to parse Avro files as delimited text. This approach ensures complete data preservation while efficiently accomplishing the file copy operation between ADLS Gen2 folders.