OrientDB：由于异步操作正在进行，因此无法执行请求

Question

当我以这种方式不止一次地查询我的OrientDb（2.2.18）时：

def orientService =  new OrientGraphFactory(url, username, password).setupPool(1, 50)

orientService.getNoTx().command(new OCommandSQL(query)).execute().toList()

我有这个：

Cannot execute the request because an asynchronous operation is in progress. Please use a different connection
DB name="MyDB"

我该如何避免它？谢谢！