Method prepareOnClusterQuery

src/Interpreters/InterpreterCreateQuery.cpp:1706–1751

}

void InterpreterCreateQuery::prepareOnClusterQuery(ASTCreateQuery & create, ContextPtr local_context, const String & cluster_name)
{
    if (create.attach)
        return;

    /// For CREATE query generate UUID on initiator, so it will be the same on all hosts.
    /// It will be ignored if database does not support UUIDs.
    generateUUIDForTable(create);

    /// For cross-replication cluster we cannot use UUID in replica path.
    String cluster_name_expanded = local_context->getMacros()->expand(cluster_name);
    ClusterPtr cluster = local_context->getCluster(cluster_name_expanded);

    if (cluster->maybeCrossReplication())
    {
        /// Check that {uuid} macro is not used in zookeeper_path for ReplicatedMergeTree.
        /// Otherwise replicas will generate different paths.
        if (!create.storage)
            return;
        if (!create.storage->engine)
            return;
        if (!startsWith(create.storage->engine->name, "Replicated"))
            return;

        bool has_explicit_zk_path_arg = create.storage->engine->arguments &&
                                        create.storage->engine->arguments->children.size() >= 2 &&
                                        create.storage->engine->arguments->children[0]->as<ASTLiteral>() &&
                                        create.storage->engine->arguments->children[0]->as<ASTLiteral>()->value.getType() == Field::Types::String;

        if (has_explicit_zk_path_arg)
        {
            String zk_path = create.storage->engine->arguments->children[0]->as<ASTLiteral>()->value.get<String>();
            Macros::MacroExpansionInfo info;
            info.table_id.uuid = create.uuid;
            info.ignore_unknown = true;
            local_context->getMacros()->expand(zk_path, info);
            if (!info.expanded_uuid)
                return;
        }

        throw Exception("Seems like cluster is configured for cross-replication, "
                        "but zookeeper_path for ReplicatedMergeTree is not specified or contains {uuid} macro. "
                        "It's not supported for cross replication, because tables must have different UUIDs. "
                        "Please specify unique zookeeper_path explicitly.", ErrorCodes::INCORRECT_QUERY);
    }
}

BlockIO InterpreterCreateQuery::execute()
{