[Hadoop Wiki] Update of "HiveDerbyServerMode" by EdwardCapriolo

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The following page has been changed by EdwardCapriolo:
http://wiki.apache.org/hadoop/HiveDerbyServerMode

New page:
== Hive using Derby in Server Mode ==

Hive in embedded mode has a limitation of 1 user. You may want to run Derby as a Network Server in this way multiple users can access it simultaneously from different systems.

=== Download Derby ===
It is suggested you download the version of derby that ships with hive. If you have already ran Hive in embedded mode the first line of derby.log contains the version. 

My structure looks like this:
{{{
/opt/hadoop/hadoop-0.17.2.1
/opt/hadoop/db-derby-10.4.1.3-bin
/opt/hadoop/hive
}}}

{{{
cd /opt/hadoop
<download>
tar -xzf db-derby-10.4.1.3-bin.tar.gz
mkdir db-derby-10.4.1.3-bin/data
}}}

=== Set environment ===
What variable to set has changed over the years. DERBY_HOME is now the proper name. I set this and the legacy name.

/etc/profile.d/derby.sh
{{{
DERBY_INSTALL=/opt/hadoop/db-derby-10.4.1.3-bin
DERBY_HOME=/opt/hadoop/db-derby-10.4.1.3-bin
export DERBY_INSTALL
export DERBY_HOME
}}}

Hive also likes to know where hadoop is installed

/etc/profile.d/hive.sh
{{{
HADOOP=/opt/hadoop/hadoop-0.17.2.1/bin/hadoop
export HADOOP
}}}

=== Starting Derby ===
Likely you are going to want to run derby when hadoop starts up. An interesting place for this other then as an lsb-init-script might be alongside hadoop scripts like start-dfs. By default derby will create databases in the directory it was started from.
{{{
cd /opt/hadoop/db-derby-10.4.1.3-bin/data
nohup /opt/hadoop/db-derby-10.4.1.3-bin/startNetworkServer -h 0.0.0.0 &
}}}

=== Configuring Hive to use Network Derby ===

/opt/hadoop/hive/conf/hive-site.xml
{{{
<property>
  <name>hive.metastore.local</name>
  <value>true</value>
  <description>controls whether to connect to remove metastore server or open a new metastore server in Hive Client JVM</description>
</property>

<property>
  <name>javax.jdo.option.ConnectionURL</name>
  <value>jdbc:derby://hadoop1:1527/metastore_db;create=true</value>
  <description>JDBC connect string for a JDBC metastore</description>
</property>

<property>
  <name>javax.jdo.option.ConnectionDriverName</name>
  <value>org.apache.derby.jdbc.ClientDriver</value>
  <description>Driver class name for a JDBC metastore</description>
</property>
}}}

/opt/hadoop/hive/conf/jpox.properties
{{{
javax.jdo.PersistenceManagerFactoryClass=org.jpox.PersistenceManagerFactoryImpl
org.jpox.autoCreateSchema=false
org.jpox.validateTables=false
org.jpox.validateColumns=false
org.jpox.validateConstraints=false
org.jpox.storeManagerType=rdbms
org.jpox.autoCreateSchema=true
org.jpox.autoStartMechanismMode=checked
org.jpox.transactionIsolation=read_committed
javax.jdo.option.DetachAllOnCommit=true
javax.jdo.option.NontransactionalRead=true
javax.jdo.option.ConnectionDriverName=org.apache.derby.jdbc.ClientDriver
javax.jdo.option.ConnectionURL=jdbc:derby://hadoop1:1527/metastore_db;create=true
javax.jdo.option.ConnectionUserName=APP
javax.jdo.option.ConnectionPassword=mine
}}}

=== Copy Derby Jar Files ===

Now since there is a new client you MUST make sure hive has these in the lib directory or in the classpath. The same would be true if you used MySQL or some other DB.

{{{
cp /opt/hadoop/db-derby-10.4.1.3-bin/lib/derbyclient.jar /opt/hadoop/hive/lib
cp /opt/hadoop/db-derby-10.4.1.3-bin/lib/derbytools.jar /opt/hadoop/hive/lib
}}}

=== Start Up Hive ===

The metastore will not be created until the first query hits it.
{{{
cd /opt/hadoop/hive
bin/hive
hive> show tables;
}}}

A directory should be created /opt/hadoop/db-derby-10.4.1.3-bin/data/metastore_db

=== The Result ===
Now you can run multiple hive instances working on the same data simultaneously and remotely.