Bug about threadlocal field in TSServiceImpl.java

There are two fields named queryStatus and queryRet:

private ThreadLocal<HashMap<String, PhysicalPlan>> queryStatus = new ThreadLocal<>();
private ThreadLocal<HashMap<String, QueryDataSet>> queryRet = new ThreadLocal<>();

They are used to save the PhysicalPlan and QueryDataSet of one query. However, the keys of both are sql string to be executed, so if the client execute the same sql in one connection, no matter whether the first execution has finished, the second sql execution will clear the first one's QueryDataSet.