Skip to content

Dataset API: Allow empty projection #24

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 1 commit into from
Jul 1, 2021
Merged

Dataset API: Allow empty projection #24

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 1 addition & 3 deletions cpp/src/jni/dataset/jni_wrapper.cc
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -590,9 +590,7 @@ JNIEXPORT jlong JNICALL Java_org_apache_arrow_dataset_jni_JniWrapper_createScann
JniAssertOkOrThrow(scanner_builder->Pool(pool));

std::vector<std::string> column_vector = ToStringVector(env, columns);
if (!column_vector.empty()) {
JniAssertOkOrThrow(scanner_builder->Project(column_vector));
}
JniAssertOkOrThrow(scanner_builder->Project(column_vector));
JniAssertOkOrThrow(scanner_builder->BatchSize(batch_size));
// initialize filters
jsize exprs_len = env->GetArrayLength(filter);
Expand Down
21 changes: 21 additions & 0 deletions java/dataset/src/test/java/org/apache/arrow/dataset/file/TestFileSystemDataset.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -137,6 +137,27 @@ public void testParquetProjector() throws Exception {
AutoCloseables.close(factory);
}

@Test
public void testEmptyProjector() throws Exception {
ParquetWriteSupport writeSupport = ParquetWriteSupport.writeTempFile(AVRO_SCHEMA_USER, TMP.newFolder(), 1, "a",
2, "b");

FileSystemDatasetFactory factory = new FileSystemDatasetFactory(rootAllocator(), NativeMemoryPool.getDefault(),
FileFormat.PARQUET, writeSupport.getOutputURI());
ScanOptions options = new ScanOptions(new String[]{}, Filter.EMPTY, 100);
Schema schema = inferResultSchemaFromFactory(factory, options);
List<ArrowRecordBatch> datum = collectResultFromFactory(factory, options);
org.apache.avro.Schema expectedSchema = truncateAvroSchema(writeSupport.getAvroSchema(), 0, 1);

assertSingleTaskProduced(factory, options);
assertEquals(0, schema.getFields().size());
assertEquals(1, datum.size());

AutoCloseables.close(datum);
AutoCloseables.close(factory);
}


@Test
public void testParquetBatchSize() throws Exception {
ParquetWriteSupport writeSupport = ParquetWriteSupport.writeTempFile(AVRO_SCHEMA_USER, TMP.newFolder(),
Expand Down