Database Reference
In-Depth Information
Chapter 6. Troubleshooting Impala
In the first part of this chapter, we are going to learn how to troubleshoot various Im-
pala issues in different categories. We will use Impala logging to understand more
about Impala execution, query processing, and possible issues. The objective of this
chapter is to provide you some critical information about Impala troubleshooting and
log analysis, so that you can manage the Impala cluster effectively and make it use-
ful for your team and yourself. Let's start with troubleshooting various problems while
managing the Impala cluster.
Troubleshooting various problems
Impala runs on DataNodes in a distributed clustered environment. So when we con-
sider the potential issues with Impala, we also need to think about the problems within
the platform itself that can impact Impala. In this section, we will cover most of these
issues along with query, connectivity, and HDFS-specific issues.
Impala configuration-related issues
If you find that Impala is not performing as expected, and you want to make sure it is
configured correctly, it is best to check the Impala configuration. With Impala installed
using Cloudera Manager, you can use the
Impala
debug web server at port 25000 to
check the Impala configuration. Here is a small list describing what you could see in
the
Impala
debug web server:
•
Impala
Configuration
Variables
List
:
ht-
tp://impala_server_name:25000/varz
•
Impala
Memory
consumption
details
:
ht-
tp://impala_server_name:25000/memz
•
Impala cluster statistics
:
http://impala_server_name:25000/met-
rics
•
All
databases
and
tables
:
http://impala_server_name:25000/
catalog
