Method dropReplicaImpl

src/Interpreters/InterpreterSystemQuery.cpp:1119–1145

}

bool InterpreterSystemQuery::dropReplicaImpl(ASTSystemQuery & query, const StoragePtr & table)
{
    auto * storage_replicated = dynamic_cast<StorageReplicatedMergeTree *>(table.get());
    if (!storage_replicated)
        return false;

    StorageReplicatedMergeTree::Status status;
    auto zookeeper = getContext()->getZooKeeper();
    storage_replicated->getStatus(status);

    /// Do not allow to drop local replicas and active remote replicas
    if (query.replica == status.replica_name)
        throw Exception("We can't drop local replica, please use `DROP TABLE` "
                        "if you want to clean the data and drop this replica", ErrorCodes::TABLE_WAS_NOT_DROPPED);

    /// NOTE it's not atomic: replica may become active after this check, but before dropReplica(...)
    /// However, the main usecase is to drop dead replica, which cannot become active.
    /// This check prevents only from accidental drop of some other replica.
    if (zookeeper->exists(status.zookeeper_path + "/replicas/" + query.replica + "/is_active"))
        throw Exception("Can't drop replica: " + query.replica + ", because it's active",
                        ErrorCodes::TABLE_WAS_NOT_DROPPED);

    storage_replicated->dropReplica(zookeeper, status.zookeeper_path, query.replica, log);
    LOG_TRACE(log, "Dropped replica {} of {}", query.replica, table->getStorageID().getNameForLogs());

    return true;
}

void InterpreterSystemQuery::recalculateMetrics(ASTSystemQuery & query)
{