mapleFU commented on code in PR #14341:
URL: https://github.com/apache/arrow/pull/14341#discussion_r1263913094
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3058,235 @@ 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> {
+ static constexpr std::string_view kEmpty = "";
+
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),
Review Comment:
encoder like this would be ok, but could you add comment for why descr could
be nullptr?
##########
cpp/src/parquet/encoding.cc:
##########
@@ -1238,43 +1240,62 @@ int PlainBooleanDecoder::Decode(bool* buffer, int
max_values) {
return max_values;
}
-struct ArrowBinaryHelper {
- explicit ArrowBinaryHelper(typename
EncodingTraits<ByteArrayType>::Accumulator* out) {
- this->out = out;
- this->builder = out->builder.get();
- this->chunk_space_remaining =
- ::arrow::kBinaryMemoryLimit - this->builder->value_data_length();
+template <typename DType, typename Enable = void>
+struct ArrowBinaryHelper;
+
+template <typename DType>
+struct ArrowBinaryHelper<DType, std::enable_if_t<std::is_same_v<DType,
ByteArrayType> ||
+ std::is_same_v<DType,
FLBAType>,
+ void>> {
+ explicit ArrowBinaryHelper(typename EncodingTraits<DType>::Accumulator* acc)
{
+ builder = acc->builder.get();
+ chunks = acc->chunks;
+ if (ARROW_PREDICT_FALSE(SubtractWithOverflow(::arrow::kBinaryMemoryLimit,
+ builder->value_data_length(),
+ &chunk_space_remaining))) {
+ throw ParquetException("excess expansion in ArrowBinaryHelper<DType>");
+ }
}
Status PushChunk() {
std::shared_ptr<::arrow::Array> result;
RETURN_NOT_OK(builder->Finish(&result));
- out->chunks.push_back(result);
+ chunks.push_back(std::move(result));
chunk_space_remaining = ::arrow::kBinaryMemoryLimit;
return Status::OK();
}
bool CanFit(int64_t length) const { return length <= chunk_space_remaining; }
void UnsafeAppend(const uint8_t* data, int32_t length) {
+ DCHECK(CanFit(length));
chunk_space_remaining -= length;
builder->UnsafeAppend(data, length);
}
void UnsafeAppendNull() { builder->UnsafeAppendNull(); }
- Status Append(const uint8_t* data, int32_t length) {
- chunk_space_remaining -= length;
- return builder->Append(data, length);
- }
+ virtual Status Append(const uint8_t* data, int32_t length);
Status AppendNull() { return builder->AppendNull(); }
- typename EncodingTraits<ByteArrayType>::Accumulator* out;
- ::arrow::BinaryBuilder* builder;
+ typename EncodingTraits<DType>::BuilderType* builder;
+ std::vector<std::shared_ptr<::arrow::Array>> chunks;
Review Comment:
This means that, when `PushChunk` called, only `chunks` pushback an element,
but `builder->chunks` not. I guess using previous:
```c++
typename EncodingTraits<ByteArrayType>::Accumulator* out;
::arrow::BinaryBuilder* builder;
```
would be ok? Or
```
typename EncodingTraits<DType>::BuilderType* builder;
std::vector<std::shared_ptr<::arrow::Array>>* chunks;
```
##########
cpp/src/parquet/encoding_test.cc:
##########
@@ -874,7 +874,7 @@ std::shared_ptr<::arrow::Array>
EncodingAdHocTyped<FLBAType>::GetValues(int seed
}
using EncodingAdHocTypedCases =
- ::testing::Types<BooleanType, Int32Type, Int64Type, FloatType, DoubleType,
FLBAType>;
+ ::testing::Types<BooleanType, Int32Type, Int64Type, FloatType, DoubleType>;
Review Comment:
Just want to make clear why we modify the builder type? Maybe I've missed
the context
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3058,235 @@ 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> {
+ static constexpr std::string_view kEmpty = "";
+
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_(descr, pool),
+ last_value_(""),
+ empty_(static_cast<uint32_t>(kEmpty.size()),
+ reinterpret_cast<const uint8_t*>(kEmpty.data())) {}
+
+ 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 VisitorType>
+ void PutInternal(const T* src, int num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ uint32_t len = descr_->type_length();
+
+ std::string_view last_value_view = last_value_;
+ constexpr int kBatchSize = 256;
+ std::array<int32_t, kBatchSize> prefix_lengths;
+ std::array<ByteArray, kBatchSize> suffixes;
+ auto visitor = VisitorType{src, len};
+
+ for (int i = 0; i < num_values; i += kBatchSize) {
+ const int batch_size = std::min(kBatchSize, num_values - i);
+
+ for (int j = 0; j < batch_size; ++j) {
+ const int idx = i + j;
+ auto view = visitor[idx];
+ len = visitor.len(idx);
+
+ uint32_t k = 0;
+ const uint32_t common_length =
+ std::min(len, static_cast<uint32_t>(last_value_view.length()));
+ while (k < common_length) {
+ if (last_value_view[k] != view[k]) {
+ break;
+ }
+ k++;
+ }
+
+ last_value_view = view;
+ prefix_lengths[j] = k;
+ const uint32_t suffix_length = len - k;
+ const uint8_t* suffix_ptr = src[idx].ptr + k;
+
+ // Convert to ByteArray, so it can be passed to the suffix_encoder_.
+ const ByteArray suffix(suffix_length, suffix_ptr);
+ suffixes[j] = suffix;
+ }
+ suffix_encoder_.Put(suffixes.data(), batch_size);
+ prefix_length_encoder_.Put(prefix_lengths.data(), batch_size);
+ }
+ last_value_ = last_value_view;
+ }
+
+ template <typename ArrayType>
+ void PutBinaryArray(const ArrayType& array) {
+ auto previous_len = static_cast<uint32_t>(last_value_.length());
+ 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 len = src.len;
+ const uint32_t common_length = std::min(previous_len, len);
Review Comment:
ditto, can we have better naming for `len` and `common_length`?
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3058,235 @@ 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> {
+ static constexpr std::string_view kEmpty = "";
+
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_(descr, pool),
+ last_value_(""),
+ empty_(static_cast<uint32_t>(kEmpty.size()),
+ reinterpret_cast<const uint8_t*>(kEmpty.data())) {}
+
+ 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 VisitorType>
+ void PutInternal(const T* src, int num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ uint32_t len = descr_->type_length();
+
+ std::string_view last_value_view = last_value_;
+ constexpr int kBatchSize = 256;
+ std::array<int32_t, kBatchSize> prefix_lengths;
+ std::array<ByteArray, kBatchSize> suffixes;
+ auto visitor = VisitorType{src, len};
+
+ for (int i = 0; i < num_values; i += kBatchSize) {
+ const int batch_size = std::min(kBatchSize, num_values - i);
+
+ for (int j = 0; j < batch_size; ++j) {
+ const int idx = i + j;
+ auto view = visitor[idx];
+ len = visitor.len(idx);
+
+ uint32_t k = 0;
+ const uint32_t common_length =
Review Comment:
I guess this is `common_length` or `maximum_common_prefix_length`, and `k`
could be `common_prefix_length`?
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3058,235 @@ 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> {
+ static constexpr std::string_view kEmpty = "";
+
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_(descr, pool),
+ last_value_(""),
+ empty_(static_cast<uint32_t>(kEmpty.size()),
+ reinterpret_cast<const uint8_t*>(kEmpty.data())) {}
+
+ 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 VisitorType>
+ void PutInternal(const T* src, int num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ uint32_t len = descr_->type_length();
+
+ std::string_view last_value_view = last_value_;
+ constexpr int kBatchSize = 256;
+ std::array<int32_t, kBatchSize> prefix_lengths;
+ std::array<ByteArray, kBatchSize> suffixes;
+ auto visitor = VisitorType{src, len};
+
+ for (int i = 0; i < num_values; i += kBatchSize) {
+ const int batch_size = std::min(kBatchSize, num_values - i);
+
+ for (int j = 0; j < batch_size; ++j) {
+ const int idx = i + j;
+ auto view = visitor[idx];
+ len = visitor.len(idx);
Review Comment:
could we use `len` from `view`? like `view.len`?
##########
cpp/src/parquet/encoding.cc:
##########
@@ -3037,12 +3058,235 @@ 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> {
+ static constexpr std::string_view kEmpty = "";
+
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_(descr, pool),
+ last_value_(""),
+ empty_(static_cast<uint32_t>(kEmpty.size()),
+ reinterpret_cast<const uint8_t*>(kEmpty.data())) {}
+
+ 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 VisitorType>
+ void PutInternal(const T* src, int num_values) {
+ if (num_values == 0) {
+ return;
+ }
+ uint32_t len = descr_->type_length();
Review Comment:
Would you mind change `len` to `flba_len` to make the code a bit more clear
--
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: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
