Add read state to string column

src/include/storage/store/column.h

@@ -47,7 +47,7 @@ class Column {
         uint64_t numValuesPerPage = UINT64_MAX;
         common::node_group_idx_t nodeGroupIdx = common::INVALID_NODE_GROUP_IDX;
         std::unique_ptr<ReadState> nullState = nullptr;
-        // Used for struct columns.
+        // Used for struct/list/string columns.
         std::vector<ReadState> childrenStates;
     };
 

src/include/storage/store/dictionary_column.h

@@ -8,17 +8,24 @@ namespace storage {
 
 class DictionaryColumn {
 public:
+    static constexpr common::vector_idx_t DATA_COLUMN_CHILD_READ_STATE_IDX = 0;
+    static constexpr common::vector_idx_t OFFSET_COLUMN_CHILD_READ_STATE_IDX = 1;
+
     DictionaryColumn(const std::string& name, const MetadataDAHInfo& metaDAHeaderInfo,
         BMFileHandle* dataFH, BMFileHandle* metadataFH, BufferManager* bufferManager, WAL* wal,
         transaction::Transaction* transaction, RWPropertyStats stats, bool enableCompression);
 
+    void initReadState(transaction::Transaction* transaction, common::node_group_idx_t nodeGroupIdx,
+        common::offset_t startOffsetInChunk, Column::ReadState& columnReadState);
+
     void append(common::node_group_idx_t nodeGroupIdx, const DictionaryChunk& dictChunk);
     void scan(transaction::Transaction* transaction, common::node_group_idx_t nodeGroupIdx,
         DictionaryChunk& dictChunk);
     // Offsets to scan should be a sorted list of pairs mapping the index of the entry in the string
     // dictionary (as read from the index column) to the output index in the result vector to store
     // the string.
-    void scan(transaction::Transaction* transaction, common::node_group_idx_t nodeGroupIdx,
+    void scan(transaction::Transaction* transaction, const Column::ReadState& offsetState,
+        const Column::ReadState& dataState,
         std::vector<std::pair<DictionaryChunk::string_index_t, uint64_t>>& offsetsToScan,
         common::ValueVector* resultVector, const ColumnChunkMetadata& indexMeta);
 

src/include/storage/store/string_column.h

@@ -12,6 +12,9 @@ class StringColumn final : public Column {
         BufferManager* bufferManager, WAL* wal, transaction::Transaction* transaction,
         RWPropertyStats propertyStatistics, bool enableCompression);
 
+    void initReadState(transaction::Transaction* transaction, common::node_group_idx_t nodeGroupIdx,
+        common::offset_t startOffsetInChunk, ReadState& columnReadState) override;
+
     void scan(transaction::Transaction* transaction, ReadState& readState,
         common::offset_t startOffsetInGroup, common::offset_t endOffsetInGroup,
         common::ValueVector* resultVector, uint64_t offsetInVector = 0) override;

src/storage/store/dictionary_column.cpp

@@ -13,7 +13,7 @@ using string_offset_t = DictionaryChunk::string_offset_t;
 
 DictionaryColumn::DictionaryColumn(const std::string& name, const MetadataDAHInfo& metaDAHeaderInfo,
     BMFileHandle* dataFH, BMFileHandle* metadataFH, BufferManager* bufferManager, WAL* wal,
-    transaction::Transaction* transaction, RWPropertyStats stats, bool enableCompression) {
+    Transaction* transaction, RWPropertyStats stats, bool enableCompression) {
     auto dataColName = StorageUtils::getColumnName(name, StorageUtils::ColumnType::DATA, "");
     dataColumn = std::make_unique<Column>(dataColName, *LogicalType::UINT8(),
         *metaDAHeaderInfo.childrenInfos[0], dataFH, metadataFH, bufferManager, wal, transaction,
@@ -24,6 +24,16 @@ DictionaryColumn::DictionaryColumn(const std::string& name, const MetadataDAHInf
         stats, enableCompression, false /*requireNullColumn*/);
 }
 
+void DictionaryColumn::initReadState(Transaction* transaction, node_group_idx_t nodeGroupIdx,
+    offset_t startOffsetInChunk, Column::ReadState& readState) {
+    // We put states for data and offset columns into childrenStates.
+    readState.childrenStates.resize(2);
+    dataColumn->initReadState(transaction, nodeGroupIdx, startOffsetInChunk,
+        readState.childrenStates[DATA_COLUMN_CHILD_READ_STATE_IDX]);
+    offsetColumn->initReadState(transaction, nodeGroupIdx, startOffsetInChunk,
+        readState.childrenStates[OFFSET_COLUMN_CHILD_READ_STATE_IDX]);
+}
+
 void DictionaryColumn::append(node_group_idx_t nodeGroupIdx, const DictionaryChunk& dictChunk) {
     KU_ASSERT(dictChunk.sanityCheck());
     dataColumn->append(dictChunk.getStringDataChunk(), nodeGroupIdx);
@@ -49,12 +59,10 @@ void DictionaryColumn::scan(Transaction* transaction, node_group_idx_t nodeGroup
     offsetColumn->scan(transaction, nodeGroupIdx, offsetChunk);
 }
 
-void DictionaryColumn::scan(Transaction* transaction, node_group_idx_t nodeGroupIdx,
+void DictionaryColumn::scan(Transaction* transaction, const Column::ReadState& offsetState,
+    const Column::ReadState& dataState,
     std::vector<std::pair<string_index_t, uint64_t>>& offsetsToScan, ValueVector* resultVector,
     const ColumnChunkMetadata& indexMeta) {
-    auto offsetState = offsetColumn->getReadState(transaction->getType(), nodeGroupIdx);
-    auto dataState = dataColumn->getReadState(transaction->getType(), nodeGroupIdx);
-
     string_index_t firstOffsetToScan, lastOffsetToScan;
     auto comp = [](auto pair1, auto pair2) { return pair1.first < pair2.first; };
     auto duplicationFactor = (double)offsetState.metadata.numValues / indexMeta.numValues;

src/storage/store/string_column.cpp

@@ -25,6 +25,12 @@ StringColumn::StringColumn(std::string name, LogicalType dataType,
       dictionary{name, metaDAHeaderInfo, dataFH, metadataFH, bufferManager, wal, transaction, stats,
           enableCompression} {}
 
+void StringColumn::initReadState(Transaction* transaction, node_group_idx_t nodeGroupIdx,
+    offset_t startOffsetInChunk, ReadState& readState) {
+    Column::initReadState(transaction, nodeGroupIdx, startOffsetInChunk, readState);
+    dictionary.initReadState(transaction, nodeGroupIdx, startOffsetInChunk, readState);
+}
+
 void StringColumn::scan(Transaction* transaction, ReadState& readState, offset_t startOffsetInGroup,
     offset_t endOffsetInGroup, ValueVector* resultVector, uint64_t offsetInVector) {
     nullColumn->scan(transaction, *readState.nullState, startOffsetInGroup, endOffsetInGroup,
@@ -121,8 +127,10 @@ void StringColumn::scanUnfiltered(transaction::Transaction* transaction, ReadSta
         // All scanned values are null
         return;
     }
-    dictionary.scan(transaction, readState.nodeGroupIdx, offsetsToScan, resultVector,
-        readState.metadata);
+    dictionary.scan(transaction,
+        readState.childrenStates[DictionaryColumn::OFFSET_COLUMN_CHILD_READ_STATE_IDX],
+        readState.childrenStates[DictionaryColumn::DATA_COLUMN_CHILD_READ_STATE_IDX], offsetsToScan,
+        resultVector, readState.metadata);
 }
 
 void StringColumn::scanFiltered(transaction::Transaction* transaction, ReadState& readState,
@@ -143,8 +151,10 @@ void StringColumn::scanFiltered(transaction::Transaction* transaction, ReadState
         // All scanned values are null
         return;
     }
-    dictionary.scan(transaction, readState.nodeGroupIdx, offsetsToScan, resultVector,
-        readState.metadata);
+    dictionary.scan(transaction,
+        readState.childrenStates[DictionaryColumn::OFFSET_COLUMN_CHILD_READ_STATE_IDX],
+        readState.childrenStates[DictionaryColumn::DATA_COLUMN_CHILD_READ_STATE_IDX], offsetsToScan,
+        resultVector, readState.metadata);
 }
 
 void StringColumn::lookupInternal(Transaction* transaction, ReadState& readState,
@@ -166,8 +176,10 @@ void StringColumn::lookupInternal(Transaction* transaction, ReadState& readState
         // All scanned values are null
         return;
     }
-    dictionary.scan(transaction, readState.nodeGroupIdx, offsetsToScan, resultVector,
-        readState.metadata);
+    dictionary.scan(transaction,
+        readState.childrenStates[DictionaryColumn::OFFSET_COLUMN_CHILD_READ_STATE_IDX],
+        readState.childrenStates[DictionaryColumn::DATA_COLUMN_CHILD_READ_STATE_IDX], offsetsToScan,
+        resultVector, readState.metadata);
 }
 
 bool StringColumn::canCommitInPlace(transaction::Transaction* transaction,