我想查询preference=_primary和routing=id2。我试过这个：
GET /bookshop/book/_search_shards?preference=_primary?routing=route2
但我得到错误：
"error": {
"root_cause": [
{
"type": "illegal_argument_exception",
"reason": "no Preference for [_primary?routing=route2]"
}
如何为路由值route2正确构建单个查询主分片？