Impala query downtime problem resolution record

Background description:
Today, the project team has added several new query functions. The theme is still to send sql statements and numbers to the impalaservice tool (a query tool made before), and then get the query results. After the template is ready, the query result is always empty. It took a long time to rule out that the hive database server was down.
[1] First check whether the syntax of the sql statement is wrong
[2] Check whether the service process in the server where impalaservice is deployed is started
[3] Use postman to send a poast request to impalaservice, and check whether there is a result
[4] Check the logs in the operation and maintenance system, Check whether the request sent by postman is received, or whether there is an exception message.

This error message is:
org.apache.thrift.transport.TTransportException: java.net.ConnectException: Connection refused
at org.apache.thrift.transport.TSocket.open( TSocket.java:185)
at org.apache.hive.jdbc.HiveConnection.openTransport(HiveConnection.java:156)
at org.apache.hive.jdbc.HiveConnection.(HiveConnection.java:96)
at org.apache.hive. jdbc.HiveDriver.connect(HiveDriver.java:104)
at com.mchange.v2.c3p0.DriverManagerDataSource.getConnection(DriverManagerDataSource.java:119)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection(WrapperConnectionPoolDataSource.java:143)
at com.mchange.v2.c3p0.WrapperConnectionPoolDataSource.getPooledConnection (WrapperConnectionPoolDataSource.java:132)
at

prompts that the connection is refused, it can be inferred that there is a problem with the database, contact the administrator to restart hive.