Impala Web User Interface for Debugging Web User Interface

web UI debug UI Each of the Impala daemons (impalad, statestored, and catalogd) includes a built-in web server that displays diagnostic and status information:

The web user interface is primarily for problem diagnosis and troubleshooting. The items listed and their formats are subject to change.

Debug Web UI for impalad

To debug and troubleshoot the impalad daemon using a web-based interface, open the URL http://impala-server-hostname:25000/ in a browser. (For secure clusters, use the prefix https:// instead of http://.) Because each Impala node produces its own set of debug information, choose a specific node that you are curious about or suspect is having problems.

Turning off the Web UI for impalad

Main Page

By default, the main page of the debug web UI is at http://impala-server-hostname:25000/ (non-secure cluster) or https://impala-server-hostname:25000/ (secure cluster).

This page lists the version of the impalad daemon, plus basic hardware and software information about the corresponding host, such as information about the CPU, memory, disks, and operating system version.

Backends Page

By default, the backends page of the debug web UI is at http://impala-server-hostname:25000/backends (non-secure cluster) or https://impala-server-hostname:25000/backends (secure cluster).

This page lists the host and port info for each of the impalad nodes in the cluster. Because each impalad daemon knows about every other impalad daemon through the statestore, this information should be the same regardless of which node you select. Links take you to the corresponding debug web pages for any of the other nodes in the cluster.

Catalog Page

By default, the catalog page of the debug web UI is at http://impala-server-hostname:25000/catalog (non-secure cluster) or https://impala-server-hostname:25000/catalog (secure cluster).

This page displays a list of databases and associated tables recognized by this instance of impalad. You can use this page to locate which database a table is in, check the exact spelling of a database or table name, look for identical table names in multiple databases, and so on.

Logs Page

By default, the logs page of the debug web UI is at http://impala-server-hostname:25000/logs (non-secure cluster) or https://impala-server-hostname:25000/logs (secure cluster).

This page shows the last portion of the impalad.INFO log file, the most detailed of the info, warning, and error logs for the impalad daemon. You can refer here to see the details of the most recent operations, whether the operations succeeded or encountered errors. This central page can be more convenient than looking around the filesystem for the log files, which could be in different locations on clusters that use cluster management software.

Memz Page

By default, the memz page of the debug web UI is at http://impala-server-hostname:25000/memz (non-secure cluster) or https://impala-server-hostname:25000/memz (secure cluster).

This page displays summary and detailed information about memory usage by the impalad daemon. You can see the memory limit in effect for the node, and how much of that memory Impala is currently using.

Metrics Page

By default, the metrics page of the debug web UI is at http://impala-server-hostname:25000/metrics (non-secure cluster) or https://impala-server-hostname:25000/metrics (secure cluster).

This page displays the current set of metrics: counters and flags representing various aspects of impalad internal operation.

Queries Page

By default, the queries page of the debug web UI is at http://impala-server-hostname:25000/queries (non-secure cluster) or https://impala-server-hostname:25000/queries (secure cluster).

This page lists all currently running queries, plus any completed queries whose details still reside in memory. The queries are listed in reverse chronological order, with the most recent at the top. (You can control the amount of memory devoted to completed queries by specifying the --query_log_size startup option for impalad.)

On this page, you can see at a glance how many SQL statements are failing (State value of EXCEPTION), how large the result sets are (# rows fetched), and how long each statement took (Start Time and End Time).

Each query has an associated link that displays the detailed query profile, which you can examine to understand the performance characteristics of that query. See for details.

Sessions Page

By default, the sessions page of the debug web UI is at http://impala-server-hostname:25000/sessions (non-secure cluster) or https://impala-server-hostname:25000/sessions (secure cluster).

This page displays information about the sessions currently connected to this impalad instance. For example, sessions could include connections from the impala-shell command, JDBC or ODBC applications, or the Impala Query UI in the Hue web interface.

Threadz Page

By default, the threadz page of the debug web UI is at http://impala-server-hostname:25000/threadz (non-secure cluster) or https://impala-server-hostname:25000/threadz (secure cluster).

This page displays information about the threads used by this instance of impalad, and shows which categories they are grouped into. Making use of this information requires substantial knowledge about Impala internals.

Varz Page

By default, the varz page of the debug web UI is at http://impala-server-hostname:25000/varz (non-secure cluster) or https://impala-server-hostname:25000/varz (secure cluster).

This page shows the configuration settings in effect when this instance of impalad communicates with other Hadoop components such as HDFS and YARN. These settings are collected from a set of configuration files; Impala might not actually make use of all settings.

The bottom of this page also lists all the command-line settings in effect for this instance of impalad. See for information about modifying these values.

Debug Web UI for statestored

Turning off the Web UI for statestored

Main Page

By default, the main page of the debug web UI is at http://impala-server-hostname:25010/ (non-secure cluster) or https://impala-server-hostname:25010/ (secure cluster).

This page lists the version of the impalad daemon, plus basic hardware and software information about the corresponding host, such as information about the CPU, memory, disks, and operating system version.

Logs Page

By default, the logs page of the debug web UI is at http://impala-server-hostname:25010/logs (non-secure cluster) or https://impala-server-hostname:25010/logs (secure cluster).

This page shows the last portion of the impalad.INFO log file, the most detailed of the info, warning, and error logs for the impalad daemon. You can refer here to see the details of the most recent operations, whether the operations succeeded or encountered errors. This central page can be more convenient than looking around the filesystem for the log files, which could be in different locations on different hosts.

Memz Page

By default, the memz page of the debug web UI is at http://impala-server-hostname:25010/memz (non-secure cluster) or https://impala-server-hostname:25010/memz (secure cluster).

This page displays summary and detailed information about memory usage by the impalad daemon. You can see the memory limit in effect for the node, and how much of that memory Impala is currently using.

Metrics Page

By default, the metrics page of the debug web UI is at http://impala-server-hostname:25010/metrics (non-secure cluster) or https://impala-server-hostname:25010/metrics (secure cluster).

This page displays the current set of metrics: counters and flags representing various aspects of impalad internal operation.

Subscribers Page

By default, the subscribers page of the debug web UI is at http://impala-server-hostname:25010/subscribers (non-secure cluster) or https://impala-server-hostname:25010/subscribers (secure cluster).

This page displays information about...

Threadz Page

By default, the threadz page of the debug web UI is at http://impala-server-hostname:25010/threadz (non-secure cluster) or https://impala-server-hostname:25010/threadz (secure cluster).

This page displays information about the threads used by this instance of impalad, and shows which categories they are grouped into. Making use of this information requires substantial knowledge about Impala internals.

Topics Page

By default, the topics page of the debug web UI is at http://impala-server-hostname:25010/topics (non-secure cluster) or https://impala-server-hostname:25010/topics (secure cluster).

This page displays information about...

Varz Page

By default, the varz page of the debug web UI is at http://impala-server-hostname:25010/varz (non-secure cluster) or https://impala-server-hostname:25010/varz (secure cluster).

This page shows the configuration settings in effect when this instance of impalad communicates with other Hadoop components such as HDFS and YARN. These settings are collected from a set of configuration files; Impala might not actually make use of all settings.

The bottom of this page also lists all the command-line settings in effect for this instance of impalad. See for information about modifying these values.

Debug Web UI for catalogd

Turning off the Web UI for impalad

Main Page

By default, the main page of the debug web UI is at http://impala-server-hostname:25020/ (non-secure cluster) or https://impala-server-hostname:25020/ (secure cluster).

This page lists the version of the impalad daemon, plus basic hardware and software information about the corresponding host, such as information about the CPU, memory, disks, and operating system version.

Catalog Page

By default, the catalog page of the debug web UI is at http://impala-server-hostname:25020/catalog (non-secure cluster) or https://impala-server-hostname:25020/catalog (secure cluster).

This page displays a list of databases and associated tables recognized by this instance of impalad. You can use this page to locate which database a table is in, check the exact spelling of a database or table name, look for identical table names in multiple databases, and so on.

Logs Page

By default, the logs page of the debug web UI is at http://impala-server-hostname:25020/logs (non-secure cluster) or https://impala-server-hostname:25020/logs (secure cluster).

This page shows the last portion of the impalad.INFO log file, the most detailed of the info, warning, and error logs for the impalad daemon. You can refer here to see the details of the most recent operations, whether the operations succeeded or encountered errors. This central page can be more convenient than looking around the filesystem for the log files, which could be in different locations on different hosts.

Metrics Page

By default, the metrics page of the debug web UI is at http://impala-server-hostname:25020/metrics (non-secure cluster) or https://impala-server-hostname:25020/metrics (secure cluster).

This page displays the current set of metrics: counters and flags representing various aspects of impalad internal operation.

Varz Page

By default, the varz page of the debug web UI is at http://impala-server-hostname:25020/varz (non-secure cluster) or https://impala-server-hostname:25020/varz (secure cluster).

This page shows the configuration settings in effect when this instance of impalad communicates with other Hadoop components such as HDFS and YARN. These settings are collected from a set of configuration files; Impala might not actually make use of all settings.

The bottom of this page also lists all the command-line settings in effect for this instance of impalad. See for information about modifying these values.