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Traditionally, !reconnect has worked to refresh a connection that has already been established. It is not able to do a fresh connect after !close has been run. As of Hive 2.1.0 (HIVE-13670), Beeline remembers the last URL successfully connected to in a session, and is able to reconnect even after a !close has been run. In addition, if a user does a !save, then this is saved in the beeline.properties file, which then allows !reconnect to connect to this saved last-connected-to URL across multiple Beeline sessions. This also allows the use of beeline -r from the command line to do a reconnect on startup.
Using hive-site.xml to automatically connect to HiveServer2
As of Hive 2.2.0 (HIVE-14063), BeeLine adds support to use the hive-site.xml present in the classpath to automatically generate a connection url based on the configuration properties in hive-site.xml and an additional user configuration file. Not all the url properties can be derived from hive-site.xml and hence in order to use this feature user must create a configuration file called “beeline-hs2-connection.xml” which is a Hadoop xml format file. This file is used to provide user-specific connection properties for the connection URL. BeeLine looks for this configuration file in ${user.home}/.beeline/ (Unix based OS) or ${user.home}\beeline\ directory (in case of Windows). If the file is not found in the above locations BeeLine looks for it in ${HIVE_CONF_DIR} location and /etc/conf/hive in that order. Once the file is found, BeeLine uses beeline-hs2-connection.xml in conjunction with the hive-site.xml in the class path to determine the connection URL.
The url connection properties in beeline-hs2-connection.xml must have the prefix “beeline.hs2.connection.” followed by the url property name. For example in order to provide the property ssl the property key in the beeline-hs2-connection.xml should be “beeline.hs2.connection.ssl”. The sample beeline.hs2.connection.xml below provides the value of user and password for the beeline connection url. In this case the rest of the properties like HS2 hostname and port information, kerberos configuration properties, SSL properties, transport mode etc are picked up using the hive-site.xml in the class path. If the password is empty beeline.hs2.connection.password property should be removed. In most cases the below configuration values in beeline-hs2-connection.xml and the correct hive-site.xml in classpath should be sufficient to make the connection to the HiveServer2.
| Code Block |
|---|
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>beeline.hs2.connection.user</name>
<value>hive</value>
</property>
<property>
<name>beeline.hs2.connection.password</name>
<value>hive</value>
</property>
</configuration> |
In case of properties which are present in both beeline-hs2-connection.xml and hive-site.xml, the property value derived from beeline-hs2-connection.xml takes precedence. For example in the below beeline-hs2-connection.xml file provides the value of principal for BeeLine connection in a kerberos enabled environment. In this case the property value for beeline.hs2.connection.principal overrides the value of HiveConf.ConfVars.HIVE_SERVER2_KERBEROS_PRINCIPAL from hive-site.xml as far as connection URL is concerned.
| Code Block |
|---|
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>beeline.hs2.connection.hosts</name>
<value>localhost:10000</value>
</property>
<property>
<name>beeline.hs2.connection.principal</name>
<value>hive/dummy-hostname@domain.com</value>
</property>
</configuration> |
In case of properties beeline.hs2.connection.hosts, beeline.hs2.connection.hiveconf and beeline.hs2.connection.hivevar property value is a comma-separated list of values. For example following beeline-hs2-connection.xml provides the hiveconf and hivevar values in a comma separated format.
| Code Block |
|---|
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>beeline.hs2.connection.user</name>
<value>hive</value>
</property>
<property>
<name>beeline.hs2.connection.hiveconf</name>
<value>hive.cli.print.current.db=true, hive.cli.print.header=true</value>
</property>
<property>
<name>beeline.hs2.connection.hivevar</name>
<value>testVarName1=value1, testVarName2=value2</value>
</property>
</configuration> |
When the beeline-hs2-connection.xml is present and when no other arguments are provided BeeLine automatically connects to the URL generated using configuration files. When connection arguments (-u, -n or -p) are provided BeeLine uses them and does not use beeline-hs2-connection.xml to automatically connect. Removing or renaming the beeline-hs2-connection.xml disables this feature.
Using JDBC
You can use JDBC to access data stored in a relational database or other tabular format.
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