Merge pull request #104878 from yanancai/master

update jdbc driver doc

Author: megvanhuygen

articles/hdinsight/hadoop/apache-hadoop-connect-hive-jdbc-driver.md

@@ -32,6 +32,18 @@ JDBC connections to an HDInsight cluster on Azure are made over port 443, and th
 
 Replace `CLUSTERNAME` with the name of your HDInsight cluster.
 
+Or you can get the connection through **Ambari UI > Hive > Configs > Advanced**.
+
+![Get JDBC connection string through Ambari](./media/apache-hadoop-connect-hive-jdbc-driver/hdinsight-get-connection-string-through-ambari.png)
+
+### Host name in connection string
+
+Host name 'CLUSTERNAME.azurehdinsight.net' in the connection string is the same as your cluster URL. You can get it through Azure portal. 
+
+### Port in connection string
+
+You can only use **port 443** to connect to the cluster from some places outside of the Azure virtual network. HDInsight is a managed service, which means that all connections to the cluster are managed via a secure Gateway. You cannot connect to HiveServer 2 directly on ports 10001 or 10000 because these ports are not exposed to the outside. 
+
 ## Authentication
 
 When establishing the connection, you must use the HDInsight cluster admin name and password to authenticate to the cluster gateway. When connecting from JDBC clients such as SQuirreL SQL, you must enter the admin name and password in client settings.
@@ -134,6 +146,15 @@ at java.util.concurrent.FutureTask.get(FutureTask.java:206)
 
 1. Restart SQuirreL. The error should no longer occur when connecting to Hive on HDInsight.
 
+### Connection disconnected by HDInsight
+
+**Symptoms**: When trying to download huge amount of data (say several GBs) through JDBC/ODBC, the connection is disconnected by HDInsight unexpectedly while downloading. 
+
+**Cause**: This error is caused by the limitation on Gateway nodes. When getting data from JDBC/ODBC, all data needs to pass through the Gateway node. However, a gateway is not designed to download a huge amount of data, so the connection might be closed by the Gateway if it cannot handle the traffic.
+
+**Resolution**: Avoid using JDBC/ODBC driver to download huge amounts of data. Copy data directly from blob storage instead.
+
+
 ## Next steps
 
 Now that you've learned how to use JDBC to work with Hive, use the following links to explore other ways to work with Azure HDInsight.