davisusanibar commented on code in PR #258:
URL: https://github.com/apache/arrow-cookbook/pull/258#discussion_r995921645
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java/source/dataset.rst:
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@@ -213,6 +213,84 @@ Query Data Content For File
2 Gladis
3 Juan
+Let's try to read a Parquet file with gzip compression and 3 row groups:
+
+.. code-block::
+
+ $ parquet-tools meta data4_3rg_gzip.parquet
+
+ file schema: schema
+ age: OPTIONAL INT64 R:0 D:1
+ name: OPTIONAL BINARY L:STRING R:0 D:1
+ row group 1: RC:4 TS:182 OFFSET:4
+ row group 2: RC:4 TS:190 OFFSET:420
+ row group 3: RC:3 TS:179 OFFSET:838
+
+.. testcode::
+
+ import org.apache.arrow.dataset.file.FileFormat;
+ import org.apache.arrow.dataset.file.FileSystemDatasetFactory;
+ import org.apache.arrow.dataset.jni.NativeMemoryPool;
+ import org.apache.arrow.dataset.scanner.ScanOptions;
+ import org.apache.arrow.dataset.scanner.Scanner;
+ import org.apache.arrow.dataset.source.Dataset;
+ import org.apache.arrow.dataset.source.DatasetFactory;
+ import org.apache.arrow.memory.BufferAllocator;
+ import org.apache.arrow.memory.RootAllocator;
+ import org.apache.arrow.vector.VectorSchemaRoot;
+ import org.apache.arrow.vector.ipc.ArrowReader;
+
+ import java.io.IOException;
+
+ String uri = "file:" + System.getProperty("user.dir") +
"/thirdpartydeps/parquetfiles/data4_3rg_gzip.parquet";
+ ScanOptions options = new ScanOptions(/*batchSize*/ 32768);
+ try (
+ BufferAllocator allocator = new RootAllocator();
+ DatasetFactory datasetFactory = new FileSystemDatasetFactory(allocator,
NativeMemoryPool.getDefault(), FileFormat.PARQUET, uri);
+ Dataset dataset = datasetFactory.finish();
+ Scanner scanner = dataset.newScan(options)
+ ) {
+ scanner.scan().forEach(scanTask -> {
+ try (ArrowReader reader = scanTask.execute()) {
Review Comment:
Yes, just updated
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