Database Reference
In-Depth Information
Configuring Impala after installation
After Impala is installed, you must perform a few mandatory and recommended con-
figuration settings for smooth Impala operations. Cloudera Manager does some of the
configurations automatically; however, a few of them need to be completed after any
kind of installation. The following is a list of post-installation configurations:
• On Cloudera Hadoop CDH 4.2 or newer distribution, the user must enable
short-circuit reads on each DataNode, after each type of installation. To en-
able short-circuit reads, here are the steps to follow on your Cloudera Hadoop
cluster:
1. First configure
hdfs-site.xml
in each DataNode as follows:
<property>
<name>dfs.client.read.shortcircuit</name>
<value>true</value>
</property>
<property>
<name>dfs.domain.socket.path</name>
<value>/var/run/hadoop-hdfs/
dn._PORT</value>
</property>
<property>
<name>dfs.client.file-block-storage-locations.timeout</name>
<value>3000</value>
</property>
2. If
/var/run/Hadoop-hdfs/
is group writable, make sure its group
is the root.
3. Copy
core-site.xml
and
hdfs-site.xml
from the Hadoop con-
figuration folder to the Impala configuration folder at
/etc/impala/
conf
.
4. Restart all DataNodes.
