Cloudera Docs

Debug Web UI for Catalog Server

The Catalog Server (catalogd) Web UI includes information about the databases, tables, and other objects managed by Impala, in addition to the resource usage and configuration settings of the catalogd.

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).

Main Page

The main catalogd Web UI page at / lists the following information about the catalogd:

  • The version of the catalogd daemon
  • Process start time
  • Hardware information
  • OS information
  • Process information
  • CGroup information
Catalog Page

The Catalog page of the debug Web UI is at /catalog under the main catalogd Web UI.

This page displays a list of databases and associated tables recognized by this instance of catalogd. 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. The catalog information is represented as the underlying Thrift data structures.

JMX

The JMX page of the catalogd debug Web UI is at /jmx under the main catalogd Web UI.

This page displays monitoring information about various JVM subsystems, such as memory pools, thread management, runtime. etc.

Java Log Level

The Change log level page of the catalogd debug Web UI is at /log_level under the main catalogd Web UI.

The page displays the current Java and backend log levels and allows you to change the log levels dynamically without having to restart the catalogd

Logs Page

The INFO logs page of the debug Web UI is at /logs under the main catalogd Web UI.

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

Memz Page

The Memory Usage page of the debug Web UI is at /memz under the main catalogd Web UI.

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

Metrics Page

The Metrics page of the debug Web UI is at /metrics under the main catalogd Web UI.

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

RPC Services Page

The RPC durations page of the catalogd debug Web UI is at /rpcz under the main catalogd Web UI.

This page displays information, such as the durations, about the RPC communications of this catalogd with other Impala daemons.

Threadz Page

The Threads page of the debug Web UI is at /threadz under the main catalogd Web UI.

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

Varz Page

The Varz page of the debug Web UI is at /varz under the main catalogd Web UI.

This page shows the configuration settings in effect when this instance of catalogd communicates with other Hadoop components such as HDFS and YARN. These settings are collected from a set of configuration files.

The bottom of this page also lists all the command-line settings in effect for this instance of catalogd.

Prometheus Metrics Page

At /metrics_prometheus, under the main catalogd Web UI, the metrics are generated in Prometheus exposition format that Prometheus can consume for event monitoring and alerting.

The /metrics_prometheus is not shown in the Web UI list of pages.