Method getCacheKey

src/Storages/StorageLog.cpp:202–214

}

String LogSource::getCacheKey(const NameAndTypePair & name_and_type_on_disk) const
{
    auto name_in_storage = name_and_type_on_disk.getNameInStorage();

    /// If this column is part of a Nested group, use the Nested name as the cache key.
    /// This ensures that all subcolumns of the same Nested (e.g. "c1.c2.64" and "c1.size0")
    /// share the same SubstreamsCache, so that shared substreams like Nested array offsets
    /// are read only once from the underlying file stream.
    if (Nested::isSubcolumnOfNested(name_in_storage, storage->columns_with_collected_nested))
        return Nested::splitName(name_in_storage).first;

    return name_in_storage;
}

Chunk LogSource::generate()
{