Sprint 2

src/lib/CMakeLists.txt

@@ -8,6 +8,8 @@ set(
     storage/abstract_segment.hpp
     storage/chunk.cpp
     storage/chunk.hpp
+    storage/dictionary_segment.cpp
+    storage/dictionary_segment.hpp
     storage/storage_manager.cpp
     storage/storage_manager.hpp
     storage/table.cpp

src/lib/storage/dictionary_segment.cpp

@@ -0,0 +1,97 @@
+#include "dictionary_segment.hpp"
+
+#include "utils/assert.hpp"
+
+namespace opossum {
+
+template <typename T>
+DictionarySegment<T>::DictionarySegment(const std::shared_ptr<AbstractSegment>& abstract_segment) {
+  // Implementation goes here
+}
+
+template <typename T>
+AllTypeVariant DictionarySegment<T>::operator[](const ChunkOffset chunk_offset) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+T DictionarySegment<T>::get(const ChunkOffset chunk_offset) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+std::optional<T> DictionarySegment<T>::get_typed_value(const ChunkOffset chunk_offset) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+const std::vector<T>& DictionarySegment<T>::dictionary() const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+std::shared_ptr<const AbstractAttributeVector> DictionarySegment<T>::attribute_vector() const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ValueID DictionarySegment<T>::null_value_id() const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+const T DictionarySegment<T>::value_of_value_id(const ValueID value_id) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ValueID DictionarySegment<T>::lower_bound(const T value) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ValueID DictionarySegment<T>::lower_bound(const AllTypeVariant& value) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ValueID DictionarySegment<T>::upper_bound(const T value) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ValueID DictionarySegment<T>::upper_bound(const AllTypeVariant& value) const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ChunkOffset DictionarySegment<T>::unique_values_count() const {
+  // Implementation goes here
+  Fail("Implementation is missing.");
+}
+
+template <typename T>
+ChunkOffset DictionarySegment<T>::size() const {
+  // Implementation goes here
+  return ChunkOffset{};
+}
+
+template <typename T>
+size_t DictionarySegment<T>::estimate_memory_usage() const {
+  return size_t{};
+}
+
+EXPLICITLY_INSTANTIATE_DATA_TYPES(DictionarySegment);
+
+}  // namespace opossum

src/lib/storage/dictionary_segment.hpp

@@ -0,0 +1,69 @@
+#pragma once
+
+#include "abstract_segment.hpp"
+
+namespace opossum {
+
+class AbstractAttributeVector;
+
+// Dictionary is a specific segment type that stores all its values in a vector
+template <typename T>
+class DictionarySegment : public AbstractSegment {
+ public:
+  /**
+   * Creates a Dictionary segment from a given value segment.
+   */
+  explicit DictionarySegment(const std::shared_ptr<AbstractSegment>& abstract_segment);
+
+  // Returns the value at a certain position. If you want to write efficient operators, back off!
+  AllTypeVariant operator[](const ChunkOffset chunk_offset) const override;
+
+  // Returns the value at a certain position. Throws an error if value is NULL.
+  T get(const ChunkOffset chunk_offset) const;
+
+  // Returns the value at a certain position. Returns std::nullopt if the value is NULL.
+  std::optional<T> get_typed_value(const ChunkOffset chunk_offset) const;
+
+  // Returns an underlying dictionary.
+  const std::vector<T>& dictionary() const;
+
+  // Returns an underlying data structure.
+  std::shared_ptr<const AbstractAttributeVector> attribute_vector() const;
+
+  // Returns the ValueID used to represent a NULL value.
+  ValueID null_value_id() const;
+
+  // Returns the value represented by a given ValueID.
+  const T value_of_value_id(const ValueID value_id) const;
+
+  // Returns the first value ID that refers to a value >= the search value. Returns INVALID_VALUE_ID if all values are
+  // smaller than the search value.
+  ValueID lower_bound(const T value) const;
+
+  // Same as lower_bound(T), but accepts an AllTypeVariant.
+  ValueID lower_bound(const AllTypeVariant& value) const;
+
+  // Returns the first value ID that refers to a value > the search value. Returns INVALID_VALUE_ID if all values are
+  // smaller than or equal to the search value.
+  ValueID upper_bound(const T value) const;
+
+  // Same as upper_bound(T), but accepts an AllTypeVariant.
+  ValueID upper_bound(const AllTypeVariant& value) const;
+
+  // Returns the number of unique_values (dictionary entries).
+  ChunkOffset unique_values_count() const;
+
+  // Returns the number of entries.
+  ChunkOffset size() const override;
+
+  // Returns the calculated memory usage.
+  size_t estimate_memory_usage() const final;
+
+ protected:
+  std::vector<T> _dictionary;
+  std::shared_ptr<AbstractAttributeVector> _attribute_vector;
+};
+
+EXPLICITLY_DECLARE_DATA_TYPES(DictionarySegment);
+
+}  // namespace opossum

src/test/CMakeLists.txt

@@ -11,6 +11,7 @@ set(
     ${SHARED_SOURCES}
     lib/all_type_variant_test.cpp
     storage/chunk_test.cpp
+    storage/dictionary_segment_test.cpp
     storage/storage_manager_test.cpp
     storage/table_test.cpp
     storage/value_segment_test.cpp

src/test/storage/dictionary_segment_test.cpp

@@ -0,0 +1,73 @@
+#include "base_test.hpp"
+
+#include "resolve_type.hpp"
+#include "storage/abstract_attribute_vector.hpp"
+#include "storage/abstract_segment.hpp"
+#include "storage/dictionary_segment.hpp"
+
+namespace opossum {
+
+class StorageDictionarySegmentTest : public BaseTest {
+ protected:
+  std::shared_ptr<ValueSegment<int32_t>> value_segment_int{std::make_shared<ValueSegment<int32_t>>()};
+  std::shared_ptr<ValueSegment<std::string>> value_segment_str{std::make_shared<ValueSegment<std::string>>(true)};
+};
+
+TEST_F(StorageDictionarySegmentTest, CompressSegmentString) {
+  value_segment_str->append("Bill");
+  value_segment_str->append("Steve");
+  value_segment_str->append("Alexander");
+  value_segment_str->append("Steve");
+  value_segment_str->append("Hasso");
+  value_segment_str->append("Bill");
+  value_segment_str->append(NULL_VALUE);
+
+  const auto dict_segment = std::make_shared<DictionarySegment<std::string>>(value_segment_str);
+
+  // Test attribute_vector size.
+  EXPECT_EQ(dict_segment->size(), 7);
+
+  // Test dictionary size (uniqueness).
+  EXPECT_EQ(dict_segment->unique_values_count(), 4);
+
+  // Test sorting.
+  const auto& dict = dict_segment->dictionary();
+  EXPECT_EQ(dict[0], "Alexander");
+  EXPECT_EQ(dict[1], "Bill");
+  EXPECT_EQ(dict[2], "Hasso");
+  EXPECT_EQ(dict[3], "Steve");
+
+  // Test NULL value handling.
+  EXPECT_EQ(dict_segment->attribute_vector()->get(6), dict_segment->null_value_id());
+  EXPECT_EQ(dict_segment->get_typed_value(6), std::nullopt);
+  EXPECT_THROW(dict_segment->get(6), std::logic_error);
+}
+
+TEST_F(StorageDictionarySegmentTest, LowerUpperBound) {
+  for (auto value = int16_t{0}; value <= 10; value += 2) {
+    value_segment_int->append(value);
+  }
+
+  std::shared_ptr<AbstractSegment> segment;
+  resolve_data_type("int", [&](auto type) {
+    using Type = typename decltype(type)::type;
+    segment = std::make_shared<DictionarySegment<Type>>(value_segment_int);
+  });
+  auto dict_segment = std::dynamic_pointer_cast<DictionarySegment<int32_t>>(segment);
+
+  EXPECT_EQ(dict_segment->lower_bound(4), ValueID{2});
+  EXPECT_EQ(dict_segment->upper_bound(4), ValueID{3});
+
+  EXPECT_EQ(dict_segment->lower_bound(AllTypeVariant{4}), ValueID{2});
+  EXPECT_EQ(dict_segment->upper_bound(AllTypeVariant{4}), ValueID{3});
+
+  EXPECT_EQ(dict_segment->lower_bound(5), ValueID{3});
+  EXPECT_EQ(dict_segment->upper_bound(5), ValueID{3});
+
+  EXPECT_EQ(dict_segment->lower_bound(15), INVALID_VALUE_ID);
+  EXPECT_EQ(dict_segment->upper_bound(15), INVALID_VALUE_ID);
+}
+
+// TODO(student): You should add some more tests here (full coverage would be appreciated) and possibly in other files.
+
+}  // namespace opossum

src/test/storage/table_test.cpp

@@ -96,4 +96,15 @@ TEST_F(StorageTableTest, SegmentsNullable) {
   EXPECT_TRUE(value_segment_2->is_nullable());
 }
 
+TEST_F(StorageTableTest, AppendWithEncodedSegments) {
+  table.append({1, "foo"});
+  EXPECT_EQ(table.row_count(), 1);
+
+  table.compress_chunk(ChunkID{0});
+  table.append({2, "bar"});
+
+  EXPECT_EQ(table.row_count(), 2);
+  EXPECT_EQ(table.chunk_count(), 2);
+}
+
 }  // namespace opossum