Web User Interface for Debugging

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

Impala Daemon Web UI

The Impala Daemon (impalad) Web UI includes information about configuration settings, running and completed queries, and associated performance and resource usage for queries. In particular, the Details link for each query displays alternative views of the query including a graphical representation of the plan, and the output of the EXPLAIN, SUMMARY, and PROFILE statements from impala-shell. Each host that runs the impalad daemon has its own instance of the Web UI, with details about those queries for which that host served as the coordinator. The impalad Web UI is primarily used for diagnosing query problems that can be traced to a particular node.

StateStore Web UI

The StateStore (statestored) Web UI includes information about memory usage, configuration settings, and ongoing health checks performed by statestored. Because there is only a single instance of the statestored within any Impala cluster, you access the Web UI only on the particular host that serves as the Impala StateStore.

Catalog Server Web UI

The Catalog Server (catalogd0 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. Because there is only a single instance of the catalogd within any Impala cluster, you access the Web UI only on the particular host that serves as the Impala Catalog Server.