h928725721 commented on issue #14411:
URL: https://github.com/apache/arrow/issues/14411#issuecomment-1280240597
`
@Slf4j
public class ValueVectorTest {
static BufferAllocator allocator = new RootAllocator();
public static void main(String[] args) {
getSchema();
}
@SneakyThrows
public static Schema getSchema() {
ByteArrayOutputStream out = writeStream();
readStream(out);
return null;
}
private static void readStream(ByteArrayOutputStream s) throws
IOException {
try (ArrowStreamReader reader = new ArrowStreamReader(new
ByteArrayInputStream(s.toByteArray()), allocator)) {
VectorSchemaRoot schemaRoot = reader.getVectorSchemaRoot();
reader.loadNextBatch();
List<FieldVector> fieldVectors = schemaRoot.getFieldVectors();
long start = System.currentTimeMillis();
fieldVectors.forEach(fieldVector -> {
long start1 = System.currentTimeMillis();
typeHandler(fieldVector);
long end1 = System.currentTimeMillis();
log.info("each time -------------------------> {}",end1 -
start1);
});
long end = System.currentTimeMillis();
log.info("total time -------------------------> {}",end - start);
}
}
private static void typeHandler(FieldVector fieldVector) {
Types.MinorType minorType = fieldVector.getMinorType();
switch (minorType) {
case BIT:
BitVector b = (BitVector) fieldVector;
int bCount = b.getValueCount();
for (int i = 0; i < bCount; i++) {
Boolean i1 = b.getObject(i);
//do something
}
break;
case VARCHAR:
VarCharVector v = (VarCharVector) fieldVector;
int vCount = v.getValueCount();
for (int i = 0; i < vCount; i++) {
Text bytes = v.getObject(i);
//do something
}
break;
}
}
private static ByteArrayOutputStream writeStream() throws IOException {
BitVector bitVector = new BitVector("boolean", allocator);
VarCharVector varCharVector = new VarCharVector("varchar",
allocator);
for (int i = 0; i < 100000000; i++) {
bitVector.setSafe(i, i % 2 == 0 ? 0 : 1);
varCharVector.setSafe(i, ("test" +
i).getBytes(StandardCharsets.UTF_8));
}
bitVector.setValueCount(100000000);
varCharVector.setValueCount(100000000);
List<Field> fields = Arrays.asList(bitVector.getField(),
varCharVector.getField());
List<FieldVector> vectors = Arrays.asList(bitVector, varCharVector);
VectorSchemaRoot root = new VectorSchemaRoot(fields, vectors);
ByteArrayOutputStream out = new ByteArrayOutputStream();
ArrowStreamWriter writer = new ArrowStreamWriter(root,
/*DictionaryProvider=*/null, Channels.newChannel(out));
writer.start();
writer.writeBatch();
for (int i = 0; i < 4; i++) {
BitVector childVector1 = (BitVector) root.getVector(0);
VarCharVector childVector2 = (VarCharVector) root.getVector(1);
childVector1.reset();
childVector2.reset();
writer.writeBatch();
}
writer.end();
return out;
}
}
`
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