src/paimon/common/reader/predicate_batch_reader.cpp

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

#include "paimon/common/reader/predicate_batch_reader.h"

#include <cassert>
#include <cstddef>
#include <cstdint>
#include <map>
#include <string>
#include <utility>
#include <vector>

#include "arrow/array/array_base.h"
#include "arrow/c/abi.h"
#include "arrow/c/bridge.h"
#include "arrow/memory_pool.h"
#include "arrow/type.h"
#include "fmt/format.h"
#include "paimon/common/predicate/predicate_filter.h"
#include "paimon/common/predicate/predicate_validator.h"
#include "paimon/common/reader/reader_utils.h"
#include "paimon/common/utils/arrow/mem_utils.h"
#include "paimon/common/utils/arrow/status_utils.h"
#include "paimon/common/utils/checked_cast.h"
#include "paimon/predicate/predicate.h"
#include "paimon/predicate/predicate_utils.h"
#include "paimon/status.h"

namespace paimon {
class MemoryPool;

PredicateBatchReader::PredicateBatchReader(std::unique_ptr<BatchReader>&& reader,
                                           const std::shared_ptr<Predicate>& predicate,
                                           const std::shared_ptr<arrow::MemoryPool>& arrow_pool)
    : arrow_pool_(arrow_pool), reader_(std::move(reader)), predicate_(predicate) {}

Result<std::unique_ptr<PredicateBatchReader>> PredicateBatchReader::Create(
    std::unique_ptr<BatchReader>&& reader, const std::shared_ptr<Predicate>& predicate,
    const std::shared_ptr<arrow::MemoryPool>& arrow_pool) {
    if (!predicate) {
        return Status::Invalid("create predicate batch reader failed. predicate is nullptr");
    }
    if (!std::dynamic_pointer_cast<PredicateFilter>(predicate)) {
        return Status::Invalid(
            fmt::format("predicate {} does not support Test", predicate->ToString()));
    }
    if (arrow_pool == nullptr) {
        return Status::Invalid("create predicate batch reader failed. arrow pool is nullptr");
    }
    return std::unique_ptr<PredicateBatchReader>(
        new PredicateBatchReader(std::move(reader), predicate, arrow_pool));
}

Result<BatchReader::ReadBatch> PredicateBatchReader::NextBatch() {
    PAIMON_ASSIGN_OR_RAISE(BatchReader::ReadBatchWithBitmap batch_with_bitmap,
                           NextBatchWithBitmap());
    PAIMON_ASSIGN_OR_RAISE(
        BatchReader::ReadBatch batch,
        ReaderUtils::ApplyBitmapToReadBatch(std::move(batch_with_bitmap), arrow_pool_));
    return batch;
}

Result<BatchReader::ReadBatchWithBitmap> PredicateBatchReader::NextBatchWithBitmap() {
    while (true) {
        PAIMON_ASSIGN_OR_RAISE(BatchReader::ReadBatchWithBitmap batch_with_bitmap,
                               reader_->NextBatchWithBitmap());
        if (BatchReader::IsEofBatch(batch_with_bitmap)) {
            return batch_with_bitmap;
        }
        auto& [batch, bitmap] = batch_with_bitmap;
        auto& [c_array, c_schema] = batch;
        assert(c_array);
        PAIMON_ASSIGN_OR_RAISE_FROM_ARROW(std::shared_ptr<arrow::Array> array,
                                          arrow::ImportArray(c_array.get(), c_schema.get()));
        PAIMON_ASSIGN_OR_RAISE(RoaringBitmap32 valid_bitmap, Filter(array));
        bitmap &= valid_bitmap;
        if (bitmap.IsEmpty()) {
            continue;
        }
        PAIMON_RETURN_NOT_OK_FROM_ARROW(arrow::ExportArray(*array, c_array.get(), c_schema.get()));
        return batch_with_bitmap;
    }
}

Status PredicateBatchReader::BindPredicateToArray(const arrow::Array& array) {
    if (array.type_id() != arrow::Type::STRUCT) {
        return Status::Invalid("predicate batch reader requires a struct array");
    }
    const auto& struct_type = checked_cast<const arrow::StructType&>(*array.type());
    std::shared_ptr<arrow::Schema> schema = arrow::schema(struct_type.fields());
    PAIMON_RETURN_NOT_OK(PredicateValidator::ValidatePredicateWithSchema(
        *schema, predicate_, /*validate_field_idx=*/false));

    std::map<std::string, int32_t> field_name_to_index;
    for (int32_t i = 0; i < schema->num_fields(); ++i) {
        field_name_to_index.emplace(schema->field(i)->name(), i);
    }
    PAIMON_ASSIGN_OR_RAISE(
        std::shared_ptr<Predicate> bound_predicate,
        PredicateUtils::CreatePickedFieldFilter(predicate_, field_name_to_index));
    predicate_filter_ = std::dynamic_pointer_cast<PredicateFilter>(bound_predicate);
    if (!predicate_filter_) {
        return Status::Invalid("failed to bind predicate to reader schema");
    }
    predicate_.reset();
    return Status::OK();
}

Result<RoaringBitmap32> PredicateBatchReader::Filter(const std::shared_ptr<arrow::Array>& array) {
    if (!predicate_filter_) {
        PAIMON_RETURN_NOT_OK(BindPredicateToArray(*array));
    }
    PAIMON_ASSIGN_OR_RAISE(std::vector<char> result,
                           predicate_filter_->Test(*array, arrow_pool_.get()));
    assert(result.size() == static_cast<size_t>(array->length()));
    RoaringBitmap32 is_valid;
    for (int32_t i = 0; i < static_cast<int32_t>(result.size()); i++) {
        if (result[i]) {
            is_valid.Add(i);
        }
    }
    return is_valid;
}

}  // namespace paimon