Method checkpointColumnChunkOutOfPlace

src/storage/table/column.cpp:448–478

}

std::vector<std::unique_ptr<ColumnChunkData>> Column::checkpointColumnChunkOutOfPlace(
    const SegmentState& state, const ColumnCheckpointState& checkpointState,
    PageAllocator& pageAllocator, bool canSplitSegment) const {
    const auto numRows = std::max(checkpointState.endRowIdxToWrite, state.metadata.numValues);
    checkpointState.persistentData.setToInMemory();
    checkpointState.persistentData.resize(numRows);
    DASSERT(checkpointState.persistentData.getNumValues() == 0);
    scanSegment(state, &checkpointState.persistentData, 0, state.metadata.numValues);
    state.reclaimAllocatedPages(pageAllocator);
    // TODO(bmwinger): for simple compression types, we can predict whether or not we will need to
    // split the segment and avoid having to re-write it multiple times
    for (auto& segmentCheckpointState : checkpointState.segmentCheckpointStates) {
        checkpointState.persistentData.write(&segmentCheckpointState.chunkData,
            segmentCheckpointState.startRowInData, segmentCheckpointState.offsetInSegment,
            segmentCheckpointState.numRows);
    }
    // Finalize is necessary prior to splitting for strings and lists so that pruned values don't
    // have an impact on the number/size of segments It should not be necessary after splitting
    // since the function is used to prune unused values (or duplicated dictionary entries in the
    // case of strings) and those will never be introduced when splitting.
    checkpointState.persistentData.finalize();
    if (canSplitSegment && checkpointState.persistentData.shouldSplit()) {
        auto newSegments = checkpointState.persistentData.split();
        for (auto& segment : newSegments) {
            segment->flush(pageAllocator);
        }
        return newSegments;
    }
    checkpointState.persistentData.flush(pageAllocator);
    return {};
}

bool Column::canCheckpointInPlace(const SegmentState& state,
    const ColumnCheckpointState& checkpointState) const {