Method removeDependency

src/Databases/TablesDependencyGraph.cpp:172–209

bool TablesDependencyGraph::removeDependency(const StorageID & table_id, const StorageID & dependency, bool remove_isolated_tables)
{
    auto * table_node = findNode(table_id);
    if (!table_node)
        return false;

    auto * dependency_node = findNode(dependency);
    if (!dependency_node)
        return false;

    auto dependency_it = table_node->dependencies.find(dependency_node);
    if (dependency_it == table_node->dependencies.end())
        return false; /// No such dependency, nothing to remove.

    table_node->dependencies.erase(dependency_it);
    bool table_node_removed = false;

    /// `dependency_node` must be updated too.
    [[maybe_unused]] bool removed_from_set = dependency_node->dependents.erase(table_node);
    chassert(removed_from_set);

    if (remove_isolated_tables && dependency_node->dependencies.empty() && dependency_node->dependents.empty())
    {
        /// The dependency table has no dependencies and no dependents now, so we will remove it from the graph.
        removeNode(dependency_node);
        if (table_node == dependency_node)
            table_node_removed = true;
    }

    if (remove_isolated_tables && !table_node_removed && table_node->dependencies.empty() && table_node->dependents.empty())
    {
        /// The table `table_id` has no dependencies and no dependents now, so we will remove it from the graph.
        removeNode(table_node);
    }

    setNeedRecalculateLevels();
    return true;
}


std::vector<StorageID> TablesDependencyGraph::removeDependencies(const StorageID & table_id, bool remove_isolated_tables)