rok commented on code in PR #14341:
URL: https://github.com/apache/arrow/pull/14341#discussion_r1195514363
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3083,243 @@ class RleBooleanDecoder : public DecoderImpl, virtual
public BooleanDecoder {
// ----------------------------------------------------------------------
// DELTA_BYTE_ARRAY
-class DeltaByteArrayDecoder : public DecoderImpl,
- virtual public TypedDecoder<ByteArrayType> {
+/// Delta Byte Array encoding also known as incremental encoding or front
compression:
+/// for each element in a sequence of strings, store the prefix length of the
previous
+/// entry plus the suffix.
+///
+/// This is stored as a sequence of delta-encoded prefix lengths
(DELTA_BINARY_PACKED),
+/// followed by the suffixes encoded as delta length byte arrays
+/// (DELTA_LENGTH_BYTE_ARRAY).
+
+// ----------------------------------------------------------------------
+// DeltaByteArrayEncoder
+
+template <typename DType>
+class DeltaByteArrayEncoder : public EncoderImpl, virtual public
TypedEncoder<DType> {
public:
- explicit DeltaByteArrayDecoder(const ColumnDescriptor* descr,
+ using T = typename DType::c_type;
+
+ explicit DeltaByteArrayEncoder(const ColumnDescriptor* descr,
MemoryPool* pool =
::arrow::default_memory_pool())
+ : EncoderImpl(descr, Encoding::DELTA_BYTE_ARRAY, pool),
+ sink_(pool),
+ prefix_length_encoder_(nullptr, pool),
+ suffix_encoder_(nullptr, pool),
+ last_value_(""),
+ kEmpty(ByteArray(0, reinterpret_cast<const uint8_t*>(""))) {}
+
+ std::shared_ptr<Buffer> FlushValues() override;
+
+ int64_t EstimatedDataEncodedSize() override {
+ return prefix_length_encoder_.EstimatedDataEncodedSize() +
+ suffix_encoder_.EstimatedDataEncodedSize();
+ }
+
+ using TypedEncoder<DType>::Put;
+
+ void Put(const ::arrow::Array& values) override;
+
+ void Put(const T* buffer, int num_values) override;
+
+ void PutSpaced(const T* src, int num_values, const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ if (valid_bits != NULLPTR) {
+ PARQUET_ASSIGN_OR_THROW(auto buffer, ::arrow::AllocateBuffer(num_values
* sizeof(T),
+
this->memory_pool()));
+ T* data = reinterpret_cast<T*>(buffer->mutable_data());
+ int num_valid_values = ::arrow::util::internal::SpacedCompress<T>(
+ src, num_values, valid_bits, valid_bits_offset, data);
+ Put(data, num_valid_values);
+ } else {
+ Put(src, num_values);
+ }
+ }
+
+ protected:
+ template <typename ArrayType>
+ void PutBinaryArray(const ArrayType& array) {
+ auto previous_len = static_cast<uint32_t>(last_value_.size());
+ std::string_view last_value_view = last_value_;
+
+ PARQUET_THROW_NOT_OK(::arrow::VisitArraySpanInline<typename
ArrayType::TypeClass>(
+ *array.data(),
+ [&](::std::string_view view) {
+ if (ARROW_PREDICT_FALSE(view.size() >= kMaxByteArraySize)) {
+ return Status::Invalid("Parquet cannot store strings with size 2GB
or more");
+ }
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray src{view};
+
+ uint32_t j = 0;
+ const uint32_t common_length = std::min(previous_len, src.len);
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+ previous_len = src.len;
+ prefix_length_encoder_.Put({static_cast<int32_t>(j)}, 1);
+
+ last_value_view = view;
+ const auto suffix_length = static_cast<uint32_t>(src.len - j);
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
+ return Status::OK();
+ }
+ const uint8_t* suffix_ptr = src.ptr + j;
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffix_encoder_.Put(&suffix, 1);
+
+ return Status::OK();
+ },
+ []() { return Status::OK(); }));
+ last_value_ = last_value_view;
+ }
+
+ ::arrow::BufferBuilder sink_;
+ DeltaBitPackEncoder<Int32Type> prefix_length_encoder_;
+ DeltaLengthByteArrayEncoder<ByteArrayType> suffix_encoder_;
+ std::string last_value_;
+ const ByteArray kEmpty;
+};
+
+template <typename DType>
+void DeltaByteArrayEncoder<DType>::Put(const T* src, int num_values) {
+ throw ParquetException("Put not implemented for " +
this->descr_->ToString());
+}
+
+template <>
+void DeltaByteArrayEncoder<ByteArrayType>::Put(const ByteArray* src, int
num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ ArrowPoolVector<int32_t> prefix_lengths(num_values,
+
::arrow::stl::allocator<int32_t>(pool_));
+ std::string_view last_value_view = last_value_;
+
+ for (int i = 0; i < num_values; i++) {
+ // Convert to ByteArray, so we can pass to the suffix_encoder_.
+ const ByteArray value = src[i];
+ if (ARROW_PREDICT_FALSE(value.len >=
static_cast<int32_t>(kMaxByteArraySize))) {
+ throw ParquetException("Parquet cannot store strings with size 2GB or
more");
+ }
+
+ auto view = string_view{reinterpret_cast<const char*>(value.ptr),
+ static_cast<uint32_t>(value.len)};
+ uint32_t j = 0;
+ const uint32_t common_length =
+ std::min(value.len, static_cast<uint32_t>(last_value_view.length()));
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+
+ last_value_view = view;
+ prefix_lengths[i] = j;
+ const auto suffix_length = static_cast<uint32_t>(value.len - j);
+
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
Review Comment:
I believe this was necessary for some compilers. I'll comment it out
temporarily to see if it's still an issue.
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3083,243 @@ class RleBooleanDecoder : public DecoderImpl, virtual
public BooleanDecoder {
// ----------------------------------------------------------------------
// DELTA_BYTE_ARRAY
-class DeltaByteArrayDecoder : public DecoderImpl,
- virtual public TypedDecoder<ByteArrayType> {
+/// Delta Byte Array encoding also known as incremental encoding or front
compression:
+/// for each element in a sequence of strings, store the prefix length of the
previous
+/// entry plus the suffix.
+///
+/// This is stored as a sequence of delta-encoded prefix lengths
(DELTA_BINARY_PACKED),
+/// followed by the suffixes encoded as delta length byte arrays
+/// (DELTA_LENGTH_BYTE_ARRAY).
+
+// ----------------------------------------------------------------------
+// DeltaByteArrayEncoder
+
+template <typename DType>
+class DeltaByteArrayEncoder : public EncoderImpl, virtual public
TypedEncoder<DType> {
public:
- explicit DeltaByteArrayDecoder(const ColumnDescriptor* descr,
+ using T = typename DType::c_type;
+
+ explicit DeltaByteArrayEncoder(const ColumnDescriptor* descr,
MemoryPool* pool =
::arrow::default_memory_pool())
+ : EncoderImpl(descr, Encoding::DELTA_BYTE_ARRAY, pool),
+ sink_(pool),
+ prefix_length_encoder_(nullptr, pool),
+ suffix_encoder_(nullptr, pool),
+ last_value_(""),
+ kEmpty(ByteArray(0, reinterpret_cast<const uint8_t*>(""))) {}
+
+ std::shared_ptr<Buffer> FlushValues() override;
+
+ int64_t EstimatedDataEncodedSize() override {
+ return prefix_length_encoder_.EstimatedDataEncodedSize() +
+ suffix_encoder_.EstimatedDataEncodedSize();
+ }
+
+ using TypedEncoder<DType>::Put;
+
+ void Put(const ::arrow::Array& values) override;
+
+ void Put(const T* buffer, int num_values) override;
+
+ void PutSpaced(const T* src, int num_values, const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ if (valid_bits != NULLPTR) {
+ PARQUET_ASSIGN_OR_THROW(auto buffer, ::arrow::AllocateBuffer(num_values
* sizeof(T),
+
this->memory_pool()));
+ T* data = reinterpret_cast<T*>(buffer->mutable_data());
+ int num_valid_values = ::arrow::util::internal::SpacedCompress<T>(
+ src, num_values, valid_bits, valid_bits_offset, data);
+ Put(data, num_valid_values);
+ } else {
+ Put(src, num_values);
+ }
+ }
+
+ protected:
+ template <typename ArrayType>
+ void PutBinaryArray(const ArrayType& array) {
+ auto previous_len = static_cast<uint32_t>(last_value_.size());
+ std::string_view last_value_view = last_value_;
+
+ PARQUET_THROW_NOT_OK(::arrow::VisitArraySpanInline<typename
ArrayType::TypeClass>(
+ *array.data(),
+ [&](::std::string_view view) {
+ if (ARROW_PREDICT_FALSE(view.size() >= kMaxByteArraySize)) {
+ return Status::Invalid("Parquet cannot store strings with size 2GB
or more");
+ }
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray src{view};
+
+ uint32_t j = 0;
+ const uint32_t common_length = std::min(previous_len, src.len);
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+ previous_len = src.len;
+ prefix_length_encoder_.Put({static_cast<int32_t>(j)}, 1);
+
+ last_value_view = view;
+ const auto suffix_length = static_cast<uint32_t>(src.len - j);
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
+ return Status::OK();
+ }
+ const uint8_t* suffix_ptr = src.ptr + j;
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffix_encoder_.Put(&suffix, 1);
+
+ return Status::OK();
+ },
+ []() { return Status::OK(); }));
+ last_value_ = last_value_view;
+ }
+
+ ::arrow::BufferBuilder sink_;
+ DeltaBitPackEncoder<Int32Type> prefix_length_encoder_;
+ DeltaLengthByteArrayEncoder<ByteArrayType> suffix_encoder_;
+ std::string last_value_;
+ const ByteArray kEmpty;
+};
+
+template <typename DType>
+void DeltaByteArrayEncoder<DType>::Put(const T* src, int num_values) {
+ throw ParquetException("Put not implemented for " +
this->descr_->ToString());
+}
+
+template <>
+void DeltaByteArrayEncoder<ByteArrayType>::Put(const ByteArray* src, int
num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ ArrowPoolVector<int32_t> prefix_lengths(num_values,
+
::arrow::stl::allocator<int32_t>(pool_));
+ std::string_view last_value_view = last_value_;
+
+ for (int i = 0; i < num_values; i++) {
+ // Convert to ByteArray, so we can pass to the suffix_encoder_.
+ const ByteArray value = src[i];
+ if (ARROW_PREDICT_FALSE(value.len >=
static_cast<int32_t>(kMaxByteArraySize))) {
+ throw ParquetException("Parquet cannot store strings with size 2GB or
more");
+ }
+
+ auto view = string_view{reinterpret_cast<const char*>(value.ptr),
+ static_cast<uint32_t>(value.len)};
+ uint32_t j = 0;
+ const uint32_t common_length =
+ std::min(value.len, static_cast<uint32_t>(last_value_view.length()));
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+
+ last_value_view = view;
+ prefix_lengths[i] = j;
+ const auto suffix_length = static_cast<uint32_t>(value.len - j);
+
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
+ continue;
+ }
+ const uint8_t* suffix_ptr = value.ptr + j;
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffix_encoder_.Put(&suffix, 1);
+ }
+ prefix_length_encoder_.Put(prefix_lengths.data(), num_values);
+ last_value_ = last_value_view;
+}
+
+template <>
+void DeltaByteArrayEncoder<FLBAType>::Put(const FLBA* src, int num_values) {
Review Comment:
Wouldn't that be a bit hard to do without making
`DeltaByteArrayEncoder<FLBAType>::Put` less efficient? (I'm not sure what the
overhead of getting len at every iteration is)
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3083,243 @@ class RleBooleanDecoder : public DecoderImpl, virtual
public BooleanDecoder {
// ----------------------------------------------------------------------
// DELTA_BYTE_ARRAY
-class DeltaByteArrayDecoder : public DecoderImpl,
- virtual public TypedDecoder<ByteArrayType> {
+/// Delta Byte Array encoding also known as incremental encoding or front
compression:
+/// for each element in a sequence of strings, store the prefix length of the
previous
+/// entry plus the suffix.
+///
+/// This is stored as a sequence of delta-encoded prefix lengths
(DELTA_BINARY_PACKED),
+/// followed by the suffixes encoded as delta length byte arrays
+/// (DELTA_LENGTH_BYTE_ARRAY).
+
+// ----------------------------------------------------------------------
+// DeltaByteArrayEncoder
+
+template <typename DType>
+class DeltaByteArrayEncoder : public EncoderImpl, virtual public
TypedEncoder<DType> {
public:
- explicit DeltaByteArrayDecoder(const ColumnDescriptor* descr,
+ using T = typename DType::c_type;
+
+ explicit DeltaByteArrayEncoder(const ColumnDescriptor* descr,
MemoryPool* pool =
::arrow::default_memory_pool())
+ : EncoderImpl(descr, Encoding::DELTA_BYTE_ARRAY, pool),
+ sink_(pool),
+ prefix_length_encoder_(nullptr, pool),
+ suffix_encoder_(nullptr, pool),
+ last_value_(""),
+ kEmpty(ByteArray(0, reinterpret_cast<const uint8_t*>(""))) {}
+
+ std::shared_ptr<Buffer> FlushValues() override;
+
+ int64_t EstimatedDataEncodedSize() override {
+ return prefix_length_encoder_.EstimatedDataEncodedSize() +
+ suffix_encoder_.EstimatedDataEncodedSize();
+ }
+
+ using TypedEncoder<DType>::Put;
+
+ void Put(const ::arrow::Array& values) override;
+
+ void Put(const T* buffer, int num_values) override;
+
+ void PutSpaced(const T* src, int num_values, const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ if (valid_bits != NULLPTR) {
+ PARQUET_ASSIGN_OR_THROW(auto buffer, ::arrow::AllocateBuffer(num_values
* sizeof(T),
+
this->memory_pool()));
+ T* data = reinterpret_cast<T*>(buffer->mutable_data());
+ int num_valid_values = ::arrow::util::internal::SpacedCompress<T>(
+ src, num_values, valid_bits, valid_bits_offset, data);
+ Put(data, num_valid_values);
+ } else {
+ Put(src, num_values);
+ }
+ }
+
+ protected:
+ template <typename ArrayType>
+ void PutBinaryArray(const ArrayType& array) {
+ auto previous_len = static_cast<uint32_t>(last_value_.size());
+ std::string_view last_value_view = last_value_;
+
+ PARQUET_THROW_NOT_OK(::arrow::VisitArraySpanInline<typename
ArrayType::TypeClass>(
+ *array.data(),
+ [&](::std::string_view view) {
+ if (ARROW_PREDICT_FALSE(view.size() >= kMaxByteArraySize)) {
+ return Status::Invalid("Parquet cannot store strings with size 2GB
or more");
+ }
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray src{view};
+
+ uint32_t j = 0;
+ const uint32_t common_length = std::min(previous_len, src.len);
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+ previous_len = src.len;
+ prefix_length_encoder_.Put({static_cast<int32_t>(j)}, 1);
+
+ last_value_view = view;
+ const auto suffix_length = static_cast<uint32_t>(src.len - j);
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
+ return Status::OK();
+ }
+ const uint8_t* suffix_ptr = src.ptr + j;
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffix_encoder_.Put(&suffix, 1);
+
+ return Status::OK();
+ },
+ []() { return Status::OK(); }));
+ last_value_ = last_value_view;
+ }
+
+ ::arrow::BufferBuilder sink_;
+ DeltaBitPackEncoder<Int32Type> prefix_length_encoder_;
+ DeltaLengthByteArrayEncoder<ByteArrayType> suffix_encoder_;
+ std::string last_value_;
+ const ByteArray kEmpty;
+};
+
+template <typename DType>
+void DeltaByteArrayEncoder<DType>::Put(const T* src, int num_values) {
+ throw ParquetException("Put not implemented for " +
this->descr_->ToString());
+}
+
+template <>
+void DeltaByteArrayEncoder<ByteArrayType>::Put(const ByteArray* src, int
num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ ArrowPoolVector<int32_t> prefix_lengths(num_values,
+
::arrow::stl::allocator<int32_t>(pool_));
Review Comment:
Changed. I'm not sure how would lockstep with (I assume you mean suffix
encoder) would work.
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3196,6 +3471,45 @@ class DeltaByteArrayDecoder : public DecoderImpl,
std::shared_ptr<ResizableBuffer> buffered_data_;
};
+class DeltaByteArrayDecoder : public DeltaByteArrayDecoderImpl<ByteArrayType> {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<ByteArrayType>;
+ using Base::DeltaByteArrayDecoderImpl;
+
+ int Decode(ByteArray* buffer, int max_values) override {
+ return GetInternal(buffer, max_values);
+ }
+};
+
+class DeltaByteArrayFLBADecoder : public DeltaByteArrayDecoderImpl<FLBAType>,
+ virtual public FLBADecoder {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<FLBAType>;
+ using Base::DeltaByteArrayDecoderImpl;
+ using Base::pool_;
+
+ int Decode(ByteArray* buffer, int max_values) {
+ return GetInternal(buffer, max_values);
+ }
+ int Decode(FixedLenByteArray* buffer, int max_values) override {
+ int decoded_values_size = max_values;
+ if (MultiplyWithOverflow(decoded_values_size,
+ descr_->type_length() * sizeof(ByteArray),
Review Comment:
Size of a buffer that values will be decoded into.
##########
cpp/src/parquet/encoding_test.cc:
##########
@@ -1955,5 +1955,293 @@ TEST(DeltaLengthByteArrayEncodingAdHoc, ArrowDirectPut)
{
CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::large_binary(),
values));
}
+// ----------------------------------------------------------------------
+// DELTA_BYTE_ARRAY encode/decode tests.
+
+template <typename Type>
+class TestDeltaByteArrayEncoding : public TestEncodingBase<Type> {
+ public:
+ using c_type = typename Type::c_type;
+ static constexpr int TYPE = Type::type_num;
+
+ void CheckRoundtrip() override {
+ auto encoder =
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ auto decoder = MakeTypedDecoder<Type>(Encoding::DELTA_BYTE_ARRAY,
descr_.get());
+
+ encoder->Put(draws_, num_values_);
+ encode_buffer_ = encoder->FlushValues();
+
+ decoder->SetData(num_values_, encode_buffer_->data(),
+ static_cast<int>(encode_buffer_->size()));
+ int values_decoded = decoder->Decode(decode_buf_, num_values_);
+ ASSERT_EQ(num_values_, values_decoded);
+ ASSERT_NO_FATAL_FAILURE(VerifyResults<c_type>(decode_buf_, draws_,
num_values_));
+ }
+
+ void CheckRoundtripSpaced(const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ auto encoder =
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ auto decoder = MakeTypedDecoder<Type>(Encoding::DELTA_BYTE_ARRAY,
descr_.get());
+ int null_count = 0;
+ for (auto i = 0; i < num_values_; i++) {
+ if (!bit_util::GetBit(valid_bits, valid_bits_offset + i)) {
+ null_count++;
+ }
+ }
+
+ encoder->PutSpaced(draws_, num_values_, valid_bits, valid_bits_offset);
+ encode_buffer_ = encoder->FlushValues();
+ decoder->SetData(num_values_ - null_count, encode_buffer_->data(),
+ static_cast<int>(encode_buffer_->size()));
+ auto values_decoded = decoder->DecodeSpaced(decode_buf_, num_values_,
null_count,
+ valid_bits, valid_bits_offset);
+ ASSERT_EQ(num_values_, values_decoded);
+ ASSERT_NO_FATAL_FAILURE(VerifyResultsSpaced<c_type>(decode_buf_, draws_,
num_values_,
+ valid_bits,
valid_bits_offset));
+ }
+
+ protected:
+ USING_BASE_MEMBERS();
+};
+
+typedef ::testing::Types<ByteArrayType, FLBAType>
TestDeltaByteArrayEncodingTypes;
+TYPED_TEST_SUITE(TestDeltaByteArrayEncoding, TestDeltaByteArrayEncodingTypes);
+
+TYPED_TEST(TestDeltaByteArrayEncoding, BasicRoundTrip) {
+ ASSERT_NO_FATAL_FAILURE(this->Execute(0, 0));
+ ASSERT_NO_FATAL_FAILURE(this->Execute(250, 2));
+ ASSERT_NO_FATAL_FAILURE(this->ExecuteSpaced(
+ /*nvalues*/ 1234, /*repeats*/ 1, /*valid_bits_offset*/ 64, /*null_prob*/
0));
+
+ ASSERT_NO_FATAL_FAILURE(this->Execute(2000, 200));
+ ASSERT_NO_FATAL_FAILURE(this->ExecuteSpaced(
+ /*nvalues*/ 1234, /*repeats*/ 10, /*valid_bits_offset*/ 64,
+ /*null_probability*/ 0.1));
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowBinaryDirectPut) {
+ const int64_t size = 50;
+ const int32_t min_length = 0;
+ const int32_t max_length = 10;
+ const int32_t num_unique = 10;
+ const double null_probability = 0.25;
+ auto encoder = MakeTypedEncoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ auto decoder = MakeTypedDecoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+
+ auto CheckSeed = [&](std::shared_ptr<::arrow::Array> values) {
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ int num_values = static_cast<int>(values->length() - values->null_count());
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<ByteArrayType>::Accumulator acc;
+ if (::arrow::is_string(values->type()->id())) {
+ acc.builder = std::make_unique<::arrow::StringBuilder>();
+ } else {
+ acc.builder = std::make_unique<::arrow::BinaryBuilder>();
+ }
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.builder->Finish(&result));
+ ASSERT_EQ(values->length(), result->length());
+ ASSERT_OK(result->ValidateFull());
+
+ auto upcast_result = CastBinaryTypesHelper(result, values->type());
+ ::arrow::AssertArraysEqual(*values, *result);
+ };
+
+ ::arrow::random::RandomArrayGenerator rag(42);
+ auto values = rag.String(0, min_length, max_length, null_probability);
+ CheckSeed(values);
+ for (auto seed : {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}) {
+ rag = ::arrow::random::RandomArrayGenerator(seed);
+
+ values = rag.String(size, min_length, max_length, null_probability);
+ CheckSeed(values);
+
+ values =
+ rag.BinaryWithRepeats(size, num_unique, min_length, max_length,
null_probability);
+ CheckSeed(values);
+ }
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowBinaryDirectPutFixedLength) {
+ const int64_t size = 50;
+ const double null_probability = 0.25;
+ ::arrow::random::RandomArrayGenerator rag(0);
+ auto encoder = MakeTypedEncoder<FLBAType>(Encoding::DELTA_BYTE_ARRAY);
+ auto decoder = MakeTypedDecoder<FLBAType>(Encoding::DELTA_BYTE_ARRAY);
+
+ auto CheckSeed = [&](std::shared_ptr<::arrow::Array> values) {
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ int num_values = static_cast<int>(values->length() - values->null_count());
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<FLBAType>::Accumulator acc(values->type());
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.Finish(&result));
+ ASSERT_EQ(values->length(), result->length());
+ ASSERT_OK(result->ValidateFull());
+ ::arrow::AssertArraysEqual(*values, *result);
+ };
+
+ for (auto seed : {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}) {
+ for (auto length : {0, 10, 100, 1000}) {
+ rag = ::arrow::random::RandomArrayGenerator(seed);
+ auto values = rag.FixedSizeBinary(size, length, null_probability);
+ CheckSeed(values);
+ }
+ }
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowDirectPut) {
+ auto CheckEncode = [](std::shared_ptr<::arrow::Array> values,
+ std::shared_ptr<::arrow::Array> prefix_lengths,
+ std::shared_ptr<::arrow::Array> suffix_lengths,
+ std::string_view value) {
+ auto encoder = MakeTypedEncoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ auto prefix_lengths_encoder =
+ MakeTypedEncoder<Int32Type>(Encoding::DELTA_BINARY_PACKED);
+ ASSERT_NO_THROW(prefix_lengths_encoder->Put(*prefix_lengths));
+ auto prefix_lengths_buf = prefix_lengths_encoder->FlushValues();
+
+ auto encoded_prefix_lengths_buf = SliceBuffer(buf, 0,
prefix_lengths_buf->size());
+
+ auto suffix_lengths_encoder =
+ MakeTypedEncoder<Int32Type>(Encoding::DELTA_BINARY_PACKED);
+ ASSERT_NO_THROW(suffix_lengths_encoder->Put(*suffix_lengths));
+ auto suffix_lengths_buf = suffix_lengths_encoder->FlushValues();
+ auto encoded_values_buf =
+ SliceBuffer(buf, prefix_lengths_buf->size() +
suffix_lengths_buf->size());
+
+ auto encoded_prefix_length_buf = SliceBuffer(buf, 0,
prefix_lengths_buf->size());
+ EXPECT_TRUE(prefix_lengths_buf->Equals(*encoded_prefix_length_buf));
+ auto encoded_suffix_length_buf =
+ SliceBuffer(buf, prefix_lengths_buf->size(),
suffix_lengths_buf->size());
+ EXPECT_TRUE(suffix_lengths_buf->Equals(*encoded_suffix_length_buf));
+ EXPECT_EQ(value, encoded_values_buf->ToString());
+ };
+
+ auto arrayToI32 = [](const std::shared_ptr<::arrow::Array>& lengths) {
+ std::vector<int32_t> arrays;
+ auto data_ptr = checked_cast<::arrow::Int32Array*>(lengths.get());
+ for (int i = 0; i < lengths->length(); ++i) {
+ arrays.push_back(data_ptr->GetView(i));
+ }
+ return arrays;
+ };
+
+ auto CheckDecode = [](std::shared_ptr<Buffer> buf,
+ std::shared_ptr<::arrow::Array> values) {
+ int num_values = static_cast<int>(values->length());
+ auto decoder = MakeTypedDecoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<ByteArrayType>::Accumulator acc;
+ if (::arrow::is_string(values->type()->id())) {
+ acc.builder = std::make_unique<::arrow::StringBuilder>();
+ } else {
+ acc.builder = std::make_unique<::arrow::BinaryBuilder>();
+ }
+
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.builder->Finish(&result));
+ ASSERT_EQ(num_values, result->length());
+ ASSERT_OK(result->ValidateFull());
+
+ auto upcast_result = CastBinaryTypesHelper(result, values->type());
+ ::arrow::AssertArraysEqual(*values, *upcast_result);
+ };
+
+ auto CheckEncodeDecode = [&](std::string_view values,
+ std::shared_ptr<::arrow::Array> prefix_lengths,
+ std::shared_ptr<::arrow::Array> suffix_lengths,
+ std::string_view suffix_data) {
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::utf8(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::large_utf8(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::binary(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::large_binary(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
Review Comment:
Indeed! Changed.
##########
cpp/src/parquet/encoding_test.cc:
##########
@@ -1955,5 +1955,293 @@ TEST(DeltaLengthByteArrayEncodingAdHoc, ArrowDirectPut)
{
CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::large_binary(),
values));
}
+// ----------------------------------------------------------------------
+// DELTA_BYTE_ARRAY encode/decode tests.
+
+template <typename Type>
+class TestDeltaByteArrayEncoding : public TestEncodingBase<Type> {
+ public:
+ using c_type = typename Type::c_type;
+ static constexpr int TYPE = Type::type_num;
+
+ void CheckRoundtrip() override {
+ auto encoder =
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ auto decoder = MakeTypedDecoder<Type>(Encoding::DELTA_BYTE_ARRAY,
descr_.get());
+
+ encoder->Put(draws_, num_values_);
+ encode_buffer_ = encoder->FlushValues();
+
+ decoder->SetData(num_values_, encode_buffer_->data(),
+ static_cast<int>(encode_buffer_->size()));
+ int values_decoded = decoder->Decode(decode_buf_, num_values_);
+ ASSERT_EQ(num_values_, values_decoded);
+ ASSERT_NO_FATAL_FAILURE(VerifyResults<c_type>(decode_buf_, draws_,
num_values_));
+ }
+
+ void CheckRoundtripSpaced(const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ auto encoder =
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ auto decoder = MakeTypedDecoder<Type>(Encoding::DELTA_BYTE_ARRAY,
descr_.get());
+ int null_count = 0;
+ for (auto i = 0; i < num_values_; i++) {
+ if (!bit_util::GetBit(valid_bits, valid_bits_offset + i)) {
+ null_count++;
+ }
+ }
+
+ encoder->PutSpaced(draws_, num_values_, valid_bits, valid_bits_offset);
+ encode_buffer_ = encoder->FlushValues();
+ decoder->SetData(num_values_ - null_count, encode_buffer_->data(),
+ static_cast<int>(encode_buffer_->size()));
+ auto values_decoded = decoder->DecodeSpaced(decode_buf_, num_values_,
null_count,
+ valid_bits, valid_bits_offset);
+ ASSERT_EQ(num_values_, values_decoded);
+ ASSERT_NO_FATAL_FAILURE(VerifyResultsSpaced<c_type>(decode_buf_, draws_,
num_values_,
+ valid_bits,
valid_bits_offset));
+ }
+
+ protected:
+ USING_BASE_MEMBERS();
+};
+
+typedef ::testing::Types<ByteArrayType, FLBAType>
TestDeltaByteArrayEncodingTypes;
+TYPED_TEST_SUITE(TestDeltaByteArrayEncoding, TestDeltaByteArrayEncodingTypes);
+
+TYPED_TEST(TestDeltaByteArrayEncoding, BasicRoundTrip) {
+ ASSERT_NO_FATAL_FAILURE(this->Execute(0, 0));
+ ASSERT_NO_FATAL_FAILURE(this->Execute(250, 2));
+ ASSERT_NO_FATAL_FAILURE(this->ExecuteSpaced(
+ /*nvalues*/ 1234, /*repeats*/ 1, /*valid_bits_offset*/ 64, /*null_prob*/
0));
+
+ ASSERT_NO_FATAL_FAILURE(this->Execute(2000, 200));
+ ASSERT_NO_FATAL_FAILURE(this->ExecuteSpaced(
+ /*nvalues*/ 1234, /*repeats*/ 10, /*valid_bits_offset*/ 64,
+ /*null_probability*/ 0.1));
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowBinaryDirectPut) {
+ const int64_t size = 50;
+ const int32_t min_length = 0;
+ const int32_t max_length = 10;
+ const int32_t num_unique = 10;
+ const double null_probability = 0.25;
+ auto encoder = MakeTypedEncoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ auto decoder = MakeTypedDecoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+
+ auto CheckSeed = [&](std::shared_ptr<::arrow::Array> values) {
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ int num_values = static_cast<int>(values->length() - values->null_count());
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<ByteArrayType>::Accumulator acc;
+ if (::arrow::is_string(values->type()->id())) {
+ acc.builder = std::make_unique<::arrow::StringBuilder>();
+ } else {
+ acc.builder = std::make_unique<::arrow::BinaryBuilder>();
+ }
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.builder->Finish(&result));
+ ASSERT_EQ(values->length(), result->length());
+ ASSERT_OK(result->ValidateFull());
+
+ auto upcast_result = CastBinaryTypesHelper(result, values->type());
+ ::arrow::AssertArraysEqual(*values, *result);
+ };
+
+ ::arrow::random::RandomArrayGenerator rag(42);
+ auto values = rag.String(0, min_length, max_length, null_probability);
+ CheckSeed(values);
+ for (auto seed : {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}) {
+ rag = ::arrow::random::RandomArrayGenerator(seed);
+
+ values = rag.String(size, min_length, max_length, null_probability);
+ CheckSeed(values);
+
+ values =
+ rag.BinaryWithRepeats(size, num_unique, min_length, max_length,
null_probability);
+ CheckSeed(values);
+ }
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowBinaryDirectPutFixedLength) {
+ const int64_t size = 50;
+ const double null_probability = 0.25;
+ ::arrow::random::RandomArrayGenerator rag(0);
+ auto encoder = MakeTypedEncoder<FLBAType>(Encoding::DELTA_BYTE_ARRAY);
+ auto decoder = MakeTypedDecoder<FLBAType>(Encoding::DELTA_BYTE_ARRAY);
+
+ auto CheckSeed = [&](std::shared_ptr<::arrow::Array> values) {
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ int num_values = static_cast<int>(values->length() - values->null_count());
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<FLBAType>::Accumulator acc(values->type());
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.Finish(&result));
+ ASSERT_EQ(values->length(), result->length());
+ ASSERT_OK(result->ValidateFull());
+ ::arrow::AssertArraysEqual(*values, *result);
+ };
+
+ for (auto seed : {0, 1, 2, 3, 4, 5, 6, 7, 8, 9}) {
+ for (auto length : {0, 10, 100, 1000}) {
+ rag = ::arrow::random::RandomArrayGenerator(seed);
+ auto values = rag.FixedSizeBinary(size, length, null_probability);
+ CheckSeed(values);
+ }
+ }
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowDirectPut) {
+ auto CheckEncode = [](std::shared_ptr<::arrow::Array> values,
+ std::shared_ptr<::arrow::Array> prefix_lengths,
+ std::shared_ptr<::arrow::Array> suffix_lengths,
+ std::string_view value) {
+ auto encoder = MakeTypedEncoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ auto prefix_lengths_encoder =
+ MakeTypedEncoder<Int32Type>(Encoding::DELTA_BINARY_PACKED);
+ ASSERT_NO_THROW(prefix_lengths_encoder->Put(*prefix_lengths));
+ auto prefix_lengths_buf = prefix_lengths_encoder->FlushValues();
+
+ auto encoded_prefix_lengths_buf = SliceBuffer(buf, 0,
prefix_lengths_buf->size());
+
+ auto suffix_lengths_encoder =
+ MakeTypedEncoder<Int32Type>(Encoding::DELTA_BINARY_PACKED);
+ ASSERT_NO_THROW(suffix_lengths_encoder->Put(*suffix_lengths));
+ auto suffix_lengths_buf = suffix_lengths_encoder->FlushValues();
+ auto encoded_values_buf =
+ SliceBuffer(buf, prefix_lengths_buf->size() +
suffix_lengths_buf->size());
+
+ auto encoded_prefix_length_buf = SliceBuffer(buf, 0,
prefix_lengths_buf->size());
+ EXPECT_TRUE(prefix_lengths_buf->Equals(*encoded_prefix_length_buf));
+ auto encoded_suffix_length_buf =
+ SliceBuffer(buf, prefix_lengths_buf->size(),
suffix_lengths_buf->size());
+ EXPECT_TRUE(suffix_lengths_buf->Equals(*encoded_suffix_length_buf));
+ EXPECT_EQ(value, encoded_values_buf->ToString());
+ };
+
+ auto arrayToI32 = [](const std::shared_ptr<::arrow::Array>& lengths) {
+ std::vector<int32_t> arrays;
+ auto data_ptr = checked_cast<::arrow::Int32Array*>(lengths.get());
+ for (int i = 0; i < lengths->length(); ++i) {
+ arrays.push_back(data_ptr->GetView(i));
+ }
+ return arrays;
+ };
+
+ auto CheckDecode = [](std::shared_ptr<Buffer> buf,
+ std::shared_ptr<::arrow::Array> values) {
+ int num_values = static_cast<int>(values->length());
+ auto decoder = MakeTypedDecoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<ByteArrayType>::Accumulator acc;
+ if (::arrow::is_string(values->type()->id())) {
+ acc.builder = std::make_unique<::arrow::StringBuilder>();
+ } else {
+ acc.builder = std::make_unique<::arrow::BinaryBuilder>();
+ }
+
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.builder->Finish(&result));
+ ASSERT_EQ(num_values, result->length());
+ ASSERT_OK(result->ValidateFull());
+
+ auto upcast_result = CastBinaryTypesHelper(result, values->type());
+ ::arrow::AssertArraysEqual(*values, *upcast_result);
+ };
+
+ auto CheckEncodeDecode = [&](std::string_view values,
+ std::shared_ptr<::arrow::Array> prefix_lengths,
+ std::shared_ptr<::arrow::Array> suffix_lengths,
+ std::string_view suffix_data) {
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::utf8(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::large_utf8(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::binary(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+ CheckEncode(::arrow::ArrayFromJSON(::arrow::large_binary(), values),
prefix_lengths,
+ suffix_lengths, suffix_data);
+
+ auto encoded =
::arrow::ConcatenateBuffers({DeltaEncode(arrayToI32(prefix_lengths)),
+
DeltaEncode(arrayToI32(suffix_lengths)),
+
std::make_shared<Buffer>(suffix_data)})
+ .ValueOrDie();
+
+ CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::utf8(), values));
+ CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::large_utf8(),
values));
+ CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::binary(), values));
+ CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::large_binary(),
values));
+ };
+
+ {
+ auto values = R"(["axis", "axle", "babble", "babyhood"])";
+ auto prefix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([0, 2,
0, 3])");
+ auto suffix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([4, 2,
6, 5])");
+
+ constexpr std::string_view suffix_data = "axislebabbleyhood";
+ CheckEncodeDecode(values, prefix_lengths, suffix_lengths, suffix_data);
+ }
+
+ {
+ auto values = R"(["axis", "axis", "axis", "axis"])";
+ auto prefix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([0, 4,
4, 4])");
+ auto suffix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([4, 0,
0, 0])");
+
+ constexpr std::string_view suffix_data = "axis";
+ CheckEncodeDecode(values, prefix_lengths, suffix_lengths, suffix_data);
+ }
+
+ {
+ auto values = R"(["axisba", "axis", "axis", "axis"])";
+ auto prefix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([0, 4,
4, 4])");
+ auto suffix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([6, 0,
0, 0])");
+
+ constexpr std::string_view suffix_data = "axisba";
+ CheckEncodeDecode(values, prefix_lengths, suffix_lengths, suffix_data);
+ }
+
+ {
+ auto values = R"(["baaxis", "axis", "axis", "axis"])";
+ auto prefix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([0, 0,
4, 4])");
+ auto suffix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([6, 4,
0, 0])");
+
+ constexpr std::string_view suffix_data = "baaxisaxis";
+ CheckEncodeDecode(values, prefix_lengths, suffix_lengths, suffix_data);
+ }
+
+ {
+ auto values = R"(["καλημέρα", "καμηλιέρη", "καμηλιέρη", "καλημέρα"])";
+ auto prefix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([0, 5,
18, 5])");
+ auto suffix_lengths = ::arrow::ArrayFromJSON(::arrow::int32(), R"([16, 13,
0, 11])");
+ const std::string suffix_data = "καλημέρα\xbcηλιέρη\xbbημέρα";
Review Comment:
Indeed.
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3083,243 @@ class RleBooleanDecoder : public DecoderImpl, virtual
public BooleanDecoder {
// ----------------------------------------------------------------------
// DELTA_BYTE_ARRAY
-class DeltaByteArrayDecoder : public DecoderImpl,
- virtual public TypedDecoder<ByteArrayType> {
+/// Delta Byte Array encoding also known as incremental encoding or front
compression:
+/// for each element in a sequence of strings, store the prefix length of the
previous
+/// entry plus the suffix.
+///
+/// This is stored as a sequence of delta-encoded prefix lengths
(DELTA_BINARY_PACKED),
+/// followed by the suffixes encoded as delta length byte arrays
+/// (DELTA_LENGTH_BYTE_ARRAY).
+
+// ----------------------------------------------------------------------
+// DeltaByteArrayEncoder
+
+template <typename DType>
+class DeltaByteArrayEncoder : public EncoderImpl, virtual public
TypedEncoder<DType> {
public:
- explicit DeltaByteArrayDecoder(const ColumnDescriptor* descr,
+ using T = typename DType::c_type;
+
+ explicit DeltaByteArrayEncoder(const ColumnDescriptor* descr,
MemoryPool* pool =
::arrow::default_memory_pool())
+ : EncoderImpl(descr, Encoding::DELTA_BYTE_ARRAY, pool),
+ sink_(pool),
+ prefix_length_encoder_(nullptr, pool),
+ suffix_encoder_(nullptr, pool),
+ last_value_(""),
+ kEmpty(ByteArray(0, reinterpret_cast<const uint8_t*>(""))) {}
+
+ std::shared_ptr<Buffer> FlushValues() override;
+
+ int64_t EstimatedDataEncodedSize() override {
+ return prefix_length_encoder_.EstimatedDataEncodedSize() +
+ suffix_encoder_.EstimatedDataEncodedSize();
+ }
+
+ using TypedEncoder<DType>::Put;
+
+ void Put(const ::arrow::Array& values) override;
+
+ void Put(const T* buffer, int num_values) override;
+
+ void PutSpaced(const T* src, int num_values, const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ if (valid_bits != NULLPTR) {
+ PARQUET_ASSIGN_OR_THROW(auto buffer, ::arrow::AllocateBuffer(num_values
* sizeof(T),
+
this->memory_pool()));
+ T* data = reinterpret_cast<T*>(buffer->mutable_data());
+ int num_valid_values = ::arrow::util::internal::SpacedCompress<T>(
+ src, num_values, valid_bits, valid_bits_offset, data);
+ Put(data, num_valid_values);
+ } else {
+ Put(src, num_values);
+ }
+ }
+
+ protected:
+ template <typename ArrayType>
+ void PutBinaryArray(const ArrayType& array) {
+ auto previous_len = static_cast<uint32_t>(last_value_.size());
+ std::string_view last_value_view = last_value_;
+
+ PARQUET_THROW_NOT_OK(::arrow::VisitArraySpanInline<typename
ArrayType::TypeClass>(
+ *array.data(),
+ [&](::std::string_view view) {
+ if (ARROW_PREDICT_FALSE(view.size() >= kMaxByteArraySize)) {
+ return Status::Invalid("Parquet cannot store strings with size 2GB
or more");
+ }
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray src{view};
+
+ uint32_t j = 0;
+ const uint32_t common_length = std::min(previous_len, src.len);
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+ previous_len = src.len;
+ prefix_length_encoder_.Put({static_cast<int32_t>(j)}, 1);
+
+ last_value_view = view;
+ const auto suffix_length = static_cast<uint32_t>(src.len - j);
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
+ return Status::OK();
+ }
+ const uint8_t* suffix_ptr = src.ptr + j;
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffix_encoder_.Put(&suffix, 1);
+
+ return Status::OK();
+ },
+ []() { return Status::OK(); }));
+ last_value_ = last_value_view;
+ }
+
+ ::arrow::BufferBuilder sink_;
+ DeltaBitPackEncoder<Int32Type> prefix_length_encoder_;
+ DeltaLengthByteArrayEncoder<ByteArrayType> suffix_encoder_;
+ std::string last_value_;
+ const ByteArray kEmpty;
+};
+
+template <typename DType>
+void DeltaByteArrayEncoder<DType>::Put(const T* src, int num_values) {
+ throw ParquetException("Put not implemented for " +
this->descr_->ToString());
+}
+
+template <>
+void DeltaByteArrayEncoder<ByteArrayType>::Put(const ByteArray* src, int
num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ ArrowPoolVector<int32_t> prefix_lengths(num_values,
+
::arrow::stl::allocator<int32_t>(pool_));
+ std::string_view last_value_view = last_value_;
+
+ for (int i = 0; i < num_values; i++) {
+ // Convert to ByteArray, so we can pass to the suffix_encoder_.
+ const ByteArray value = src[i];
+ if (ARROW_PREDICT_FALSE(value.len >=
static_cast<int32_t>(kMaxByteArraySize))) {
+ throw ParquetException("Parquet cannot store strings with size 2GB or
more");
+ }
+
+ auto view = string_view{reinterpret_cast<const char*>(value.ptr),
+ static_cast<uint32_t>(value.len)};
Review Comment:
Done. Also changed at line ~3405.
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3083,243 @@ class RleBooleanDecoder : public DecoderImpl, virtual
public BooleanDecoder {
// ----------------------------------------------------------------------
// DELTA_BYTE_ARRAY
-class DeltaByteArrayDecoder : public DecoderImpl,
- virtual public TypedDecoder<ByteArrayType> {
+/// Delta Byte Array encoding also known as incremental encoding or front
compression:
+/// for each element in a sequence of strings, store the prefix length of the
previous
+/// entry plus the suffix.
+///
+/// This is stored as a sequence of delta-encoded prefix lengths
(DELTA_BINARY_PACKED),
+/// followed by the suffixes encoded as delta length byte arrays
+/// (DELTA_LENGTH_BYTE_ARRAY).
+
+// ----------------------------------------------------------------------
+// DeltaByteArrayEncoder
+
+template <typename DType>
+class DeltaByteArrayEncoder : public EncoderImpl, virtual public
TypedEncoder<DType> {
public:
- explicit DeltaByteArrayDecoder(const ColumnDescriptor* descr,
+ using T = typename DType::c_type;
+
+ explicit DeltaByteArrayEncoder(const ColumnDescriptor* descr,
MemoryPool* pool =
::arrow::default_memory_pool())
+ : EncoderImpl(descr, Encoding::DELTA_BYTE_ARRAY, pool),
+ sink_(pool),
+ prefix_length_encoder_(nullptr, pool),
+ suffix_encoder_(nullptr, pool),
+ last_value_(""),
+ kEmpty(ByteArray(0, reinterpret_cast<const uint8_t*>(""))) {}
+
+ std::shared_ptr<Buffer> FlushValues() override;
+
+ int64_t EstimatedDataEncodedSize() override {
+ return prefix_length_encoder_.EstimatedDataEncodedSize() +
+ suffix_encoder_.EstimatedDataEncodedSize();
+ }
+
+ using TypedEncoder<DType>::Put;
+
+ void Put(const ::arrow::Array& values) override;
+
+ void Put(const T* buffer, int num_values) override;
+
+ void PutSpaced(const T* src, int num_values, const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ if (valid_bits != NULLPTR) {
+ PARQUET_ASSIGN_OR_THROW(auto buffer, ::arrow::AllocateBuffer(num_values
* sizeof(T),
+
this->memory_pool()));
+ T* data = reinterpret_cast<T*>(buffer->mutable_data());
+ int num_valid_values = ::arrow::util::internal::SpacedCompress<T>(
+ src, num_values, valid_bits, valid_bits_offset, data);
+ Put(data, num_valid_values);
+ } else {
+ Put(src, num_values);
+ }
+ }
+
+ protected:
+ template <typename ArrayType>
+ void PutBinaryArray(const ArrayType& array) {
+ auto previous_len = static_cast<uint32_t>(last_value_.size());
+ std::string_view last_value_view = last_value_;
+
+ PARQUET_THROW_NOT_OK(::arrow::VisitArraySpanInline<typename
ArrayType::TypeClass>(
+ *array.data(),
+ [&](::std::string_view view) {
+ if (ARROW_PREDICT_FALSE(view.size() >= kMaxByteArraySize)) {
+ return Status::Invalid("Parquet cannot store strings with size 2GB
or more");
+ }
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray src{view};
+
+ uint32_t j = 0;
+ const uint32_t common_length = std::min(previous_len, src.len);
+ while (j < common_length) {
+ if (last_value_view[j] != view[j]) {
+ break;
+ }
+ j++;
+ }
+ previous_len = src.len;
+ prefix_length_encoder_.Put({static_cast<int32_t>(j)}, 1);
+
+ last_value_view = view;
+ const auto suffix_length = static_cast<uint32_t>(src.len - j);
+ if (suffix_length == 0) {
+ suffix_encoder_.Put(&kEmpty, 1);
+ return Status::OK();
+ }
+ const uint8_t* suffix_ptr = src.ptr + j;
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffix_encoder_.Put(&suffix, 1);
+
+ return Status::OK();
+ },
+ []() { return Status::OK(); }));
+ last_value_ = last_value_view;
+ }
+
+ ::arrow::BufferBuilder sink_;
+ DeltaBitPackEncoder<Int32Type> prefix_length_encoder_;
+ DeltaLengthByteArrayEncoder<ByteArrayType> suffix_encoder_;
+ std::string last_value_;
+ const ByteArray kEmpty;
+};
+
+template <typename DType>
+void DeltaByteArrayEncoder<DType>::Put(const T* src, int num_values) {
+ throw ParquetException("Put not implemented for " +
this->descr_->ToString());
Review Comment:
Indeed. Removed.
##########
cpp/src/parquet/encoding_test.cc:
##########
@@ -1955,5 +1955,293 @@ TEST(DeltaLengthByteArrayEncodingAdHoc, ArrowDirectPut)
{
CheckDecode(encoded, ::arrow::ArrayFromJSON(::arrow::large_binary(),
values));
}
+// ----------------------------------------------------------------------
+// DELTA_BYTE_ARRAY encode/decode tests.
+
+template <typename Type>
+class TestDeltaByteArrayEncoding : public TestEncodingBase<Type> {
+ public:
+ using c_type = typename Type::c_type;
+ static constexpr int TYPE = Type::type_num;
+
+ void CheckRoundtrip() override {
+ auto encoder =
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ auto decoder = MakeTypedDecoder<Type>(Encoding::DELTA_BYTE_ARRAY,
descr_.get());
+
+ encoder->Put(draws_, num_values_);
+ encode_buffer_ = encoder->FlushValues();
+
+ decoder->SetData(num_values_, encode_buffer_->data(),
+ static_cast<int>(encode_buffer_->size()));
+ int values_decoded = decoder->Decode(decode_buf_, num_values_);
+ ASSERT_EQ(num_values_, values_decoded);
+ ASSERT_NO_FATAL_FAILURE(VerifyResults<c_type>(decode_buf_, draws_,
num_values_));
+ }
+
+ void CheckRoundtripSpaced(const uint8_t* valid_bits,
+ int64_t valid_bits_offset) override {
+ auto encoder =
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ auto decoder = MakeTypedDecoder<Type>(Encoding::DELTA_BYTE_ARRAY,
descr_.get());
+ int null_count = 0;
+ for (auto i = 0; i < num_values_; i++) {
+ if (!bit_util::GetBit(valid_bits, valid_bits_offset + i)) {
+ null_count++;
+ }
+ }
+
+ encoder->PutSpaced(draws_, num_values_, valid_bits, valid_bits_offset);
+ encode_buffer_ = encoder->FlushValues();
+ decoder->SetData(num_values_ - null_count, encode_buffer_->data(),
+ static_cast<int>(encode_buffer_->size()));
+ auto values_decoded = decoder->DecodeSpaced(decode_buf_, num_values_,
null_count,
+ valid_bits, valid_bits_offset);
+ ASSERT_EQ(num_values_, values_decoded);
+ ASSERT_NO_FATAL_FAILURE(VerifyResultsSpaced<c_type>(decode_buf_, draws_,
num_values_,
+ valid_bits,
valid_bits_offset));
+ }
+
+ protected:
+ USING_BASE_MEMBERS();
+};
+
+typedef ::testing::Types<ByteArrayType, FLBAType>
TestDeltaByteArrayEncodingTypes;
+TYPED_TEST_SUITE(TestDeltaByteArrayEncoding, TestDeltaByteArrayEncodingTypes);
+
+TYPED_TEST(TestDeltaByteArrayEncoding, BasicRoundTrip) {
+ ASSERT_NO_FATAL_FAILURE(this->Execute(0, 0));
+ ASSERT_NO_FATAL_FAILURE(this->Execute(250, 2));
+ ASSERT_NO_FATAL_FAILURE(this->ExecuteSpaced(
+ /*nvalues*/ 1234, /*repeats*/ 1, /*valid_bits_offset*/ 64, /*null_prob*/
0));
+
+ ASSERT_NO_FATAL_FAILURE(this->Execute(2000, 200));
+ ASSERT_NO_FATAL_FAILURE(this->ExecuteSpaced(
+ /*nvalues*/ 1234, /*repeats*/ 10, /*valid_bits_offset*/ 64,
+ /*null_probability*/ 0.1));
+}
+
+TEST(DeltaByteArrayEncodingAdHoc, ArrowBinaryDirectPut) {
+ const int64_t size = 50;
+ const int32_t min_length = 0;
+ const int32_t max_length = 10;
+ const int32_t num_unique = 10;
+ const double null_probability = 0.25;
+ auto encoder = MakeTypedEncoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+ auto decoder = MakeTypedDecoder<ByteArrayType>(Encoding::DELTA_BYTE_ARRAY);
+
+ auto CheckSeed = [&](std::shared_ptr<::arrow::Array> values) {
+ ASSERT_NO_THROW(encoder->Put(*values));
+ auto buf = encoder->FlushValues();
+
+ int num_values = static_cast<int>(values->length() - values->null_count());
+ decoder->SetData(num_values, buf->data(), static_cast<int>(buf->size()));
+
+ typename EncodingTraits<ByteArrayType>::Accumulator acc;
+ if (::arrow::is_string(values->type()->id())) {
+ acc.builder = std::make_unique<::arrow::StringBuilder>();
+ } else {
+ acc.builder = std::make_unique<::arrow::BinaryBuilder>();
+ }
+ ASSERT_EQ(num_values,
+ decoder->DecodeArrow(static_cast<int>(values->length()),
+ static_cast<int>(values->null_count()),
+ values->null_bitmap_data(),
values->offset(), &acc));
+
+ std::shared_ptr<::arrow::Array> result;
+ ASSERT_OK(acc.builder->Finish(&result));
+ ASSERT_EQ(values->length(), result->length());
+ ASSERT_OK(result->ValidateFull());
+
+ auto upcast_result = CastBinaryTypesHelper(result, values->type());
Review Comment:
Removing where unnecessary.
`CastBinaryTypesHelper` casts (`utf8`, `large_utf8`)->`large_utf8` and
(`binary`, `large_binary`)->`large_binary`. This is then used in `CheckDecode`
(used in `TEST(DeltaLengthByteArrayEncodingAdHoc, ArrowDirectPut)` and
`TEST(DeltaByteArrayEncodingAdHoc, ArrowDirectPut)`) to be able to compare all
decoded (upcast) results against the same input values.
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3196,6 +3471,45 @@ class DeltaByteArrayDecoder : public DecoderImpl,
std::shared_ptr<ResizableBuffer> buffered_data_;
};
+class DeltaByteArrayDecoder : public DeltaByteArrayDecoderImpl<ByteArrayType> {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<ByteArrayType>;
+ using Base::DeltaByteArrayDecoderImpl;
+
+ int Decode(ByteArray* buffer, int max_values) override {
+ return GetInternal(buffer, max_values);
+ }
+};
+
+class DeltaByteArrayFLBADecoder : public DeltaByteArrayDecoderImpl<FLBAType>,
+ virtual public FLBADecoder {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<FLBAType>;
+ using Base::DeltaByteArrayDecoderImpl;
+ using Base::pool_;
+
+ int Decode(ByteArray* buffer, int max_values) {
+ return GetInternal(buffer, max_values);
+ }
+ int Decode(FixedLenByteArray* buffer, int max_values) override {
+ int decoded_values_size = max_values;
+ if (MultiplyWithOverflow(decoded_values_size,
+ descr_->type_length() * sizeof(ByteArray),
+ &decoded_values_size)) {
+ throw ParquetException("excess expansion in DELTA_LENGTH_BYTE_ARRAY");
+ }
+ ArrowPoolVector<uint8_t> decode_values(decoded_values_size,
+
::arrow::stl::allocator<uint8_t>(pool_));
+ auto decode_buf = reinterpret_cast<ByteArray*>(decode_values.data());
Review Comment:
Because `GetInternal` takes `ByteArray*` (`GetInternal(ByteArray* buffer,
int max_values)`). I might be missing your point :).
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3196,6 +3471,45 @@ class DeltaByteArrayDecoder : public DecoderImpl,
std::shared_ptr<ResizableBuffer> buffered_data_;
};
+class DeltaByteArrayDecoder : public DeltaByteArrayDecoderImpl<ByteArrayType> {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<ByteArrayType>;
+ using Base::DeltaByteArrayDecoderImpl;
+
+ int Decode(ByteArray* buffer, int max_values) override {
+ return GetInternal(buffer, max_values);
+ }
+};
+
+class DeltaByteArrayFLBADecoder : public DeltaByteArrayDecoderImpl<FLBAType>,
+ virtual public FLBADecoder {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<FLBAType>;
+ using Base::DeltaByteArrayDecoderImpl;
+ using Base::pool_;
+
+ int Decode(ByteArray* buffer, int max_values) {
+ return GetInternal(buffer, max_values);
+ }
+ int Decode(FixedLenByteArray* buffer, int max_values) override {
+ int decoded_values_size = max_values;
+ if (MultiplyWithOverflow(decoded_values_size,
+ descr_->type_length() * sizeof(ByteArray),
+ &decoded_values_size)) {
+ throw ParquetException("excess expansion in DELTA_LENGTH_BYTE_ARRAY");
+ }
+ ArrowPoolVector<uint8_t> decode_values(decoded_values_size,
+
::arrow::stl::allocator<uint8_t>(pool_));
+ auto decode_buf = reinterpret_cast<ByteArray*>(decode_values.data());
+
+ max_values = GetInternal(decode_buf, max_values);
+ for (int i = 0; i < max_values; i++) {
+ buffer[i].ptr = decode_buf->ptr + i * descr_->type_length();
Review Comment:
At `3505` we decode to `ByteArray` and then copy it value by value into
`FixedLenByteArray` at `3507`. We assume uniform length because original source
(before encoding) was `FixedLenByteArray` (this might be assuming too much
though).
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3196,6 +3471,45 @@ class DeltaByteArrayDecoder : public DecoderImpl,
std::shared_ptr<ResizableBuffer> buffered_data_;
};
+class DeltaByteArrayDecoder : public DeltaByteArrayDecoderImpl<ByteArrayType> {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<ByteArrayType>;
+ using Base::DeltaByteArrayDecoderImpl;
+
+ int Decode(ByteArray* buffer, int max_values) override {
+ return GetInternal(buffer, max_values);
+ }
+};
+
+class DeltaByteArrayFLBADecoder : public DeltaByteArrayDecoderImpl<FLBAType>,
+ virtual public FLBADecoder {
+ public:
+ using Base = DeltaByteArrayDecoderImpl<FLBAType>;
+ using Base::DeltaByteArrayDecoderImpl;
+ using Base::pool_;
+
+ int Decode(ByteArray* buffer, int max_values) {
Review Comment:
Removing.
##########
cpp/src/parquet/encoding_test.cc:
##########
@@ -1966,7 +1966,7 @@ class TestDeltaByteArrayEncoding : public
TestEncodingBase<Type> {
void CheckRoundtrip() override {
auto encoder =
- MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, false,
descr_.get());
+ MakeTypedEncoder<Type>(Encoding::DELTA_BYTE_ARRAY, /*xxx=*/ false,
descr_.get());
Review Comment:
Done.
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3409,6 +3723,16 @@ std::unique_ptr<Encoder> MakeEncoder(Type::type
type_num, Encoding::type encodin
default:
throw ParquetException("RLE only supports BOOLEAN");
}
+ } else if (encoding == Encoding::DELTA_BYTE_ARRAY) {
+ switch (type_num) {
+ case Type::BYTE_ARRAY:
+ return std::make_unique<DeltaByteArrayEncoder<ByteArrayType>>(descr,
pool);
+ case Type::FIXED_LEN_BYTE_ARRAY:
+ return std::make_unique<DeltaByteArrayEncoder<FLBAType>>(descr, pool);
Review Comment:
It was motivated by https://github.com/apache/parquet-format/pull/189. I can
split it out if necessary.
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