wgtmac commented on code in PR #1026: URL: https://github.com/apache/parquet-mr/pull/1026#discussion_r1104610792
########## parquet-hadoop/src/main/java/org/apache/parquet/hadoop/rewrite/ParquetRewriter.java: ########## @@ -183,12 +186,61 @@ public ParquetRewriter(TransParquetFileReader reader, } } + // Open all input files to validate their schemas are compatible to merge + private void openInputFiles(List<Path> inputFiles, Configuration conf) { + Preconditions.checkArgument(inputFiles != null && !inputFiles.isEmpty(), "No input files"); + + for (Path inputFile : inputFiles) { + try { + TransParquetFileReader reader = new TransParquetFileReader( + HadoopInputFile.fromPath(inputFile, conf), HadoopReadOptions.builder(conf).build()); + MessageType inputFileSchema = reader.getFooter().getFileMetaData().getSchema(); + if (this.schema == null) { + this.schema = inputFileSchema; + } else { + // Now we enforce equality of schemas from input files for simplicity. + if (!this.schema.equals(inputFileSchema)) { + throw new InvalidSchemaException("Input files have different schemas"); + } + } + this.allOriginalCreatedBys.add(reader.getFooter().getFileMetaData().getCreatedBy()); + this.inputFiles.add(reader); + } catch (IOException e) { + throw new IllegalArgumentException("Failed to open input file: " + inputFile, e); + } + } + + extraMetaData.put(ORIGINAL_CREATED_BY_KEY, String.join("\n", allOriginalCreatedBys)); Review Comment: We have discussed the issue to consolidate original created_by when merging several input files. Now I use a HashSet to make sure there is no duplicate and they are concatenated by `\n`. Does this sound good? @gszadovszky -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: dev-unsubscr...@parquet.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org