我正在尝试查找字段以值开头的文档。使用notablescan禁用表扫描.这行得通:db.articles.find({"url":{$regex:/^http/}})这不是:db.articles.find({"source.homeUrl":{$regex:/^http/}})我得到错误:error:{"$err":"tablescansnotallowed:moreover.articles","code":10111}url和source.homeUrl都有索引:{"v":1,"key":{"url":1},"ns":"mydb.articles","name":"url_1"}