PoolPage — Fair Scheduler Pool Details Page

PoolPage is a WebUIPage with pool prefix.

The Fair Scheduler Pool Details page shows information about a Schedulable pool and is only available when a Spark application uses the FAIR scheduling mode (which is controlled by spark.scheduler.mode configuration property).

spark webui pool details
Figure 1. Details Page for production Pool

PoolPage renders a page under /pool URL and requires one request parameter poolname that is the name of the pool to display, e.g. http://localhost:4040/stages/pool/?poolname=production. It is made up of two tables: Summary (with the details of the pool) and Active Stages (with the active stages in the pool).

PoolPage is created exclusively when StagesTab is created.

PoolPage takes a StagesTab when created.

PoolPage uses the parent’s SparkContext to access information about the pool and JobProgressListener for active stages in the pool (sorted by submissionTime in descending order by default).

Summary Table

The Summary table shows the details of a Schedulable pool.

spark webui pool summary
Figure 2. Summary for production Pool

It uses the following columns:

  • Pool Name

  • Minimum Share

  • Pool Weight

  • Active Stages - the number of the active stages in a Schedulable pool.

  • Running Tasks

  • SchedulingMode

All the columns are the attributes of a Schedulable but the number of active stages which is calculated using the list of active stages of a pool (from the parent’s JobProgressListener).

Active Stages Table

The Active Stages table shows the active stages in a pool.

spark webui active stages
Figure 3. Active Stages for production Pool

It uses the following columns:

  • Stage Id

  • (optional) Pool Name - only available when in FAIR scheduling mode.

  • Description

  • Submitted

  • Duration

  • Tasks: Succeeded/Total

  • Input — Bytes and records read from Hadoop or from Spark storage.

  • Output — Bytes and records written to Hadoop.

  • Shuffle Read — Total shuffle bytes and records read (includes both data read locally and data read from remote executors).

  • Shuffle Write — Bytes and records written to disk in order to be read by a shuffle in a future stage.

Request Parameters


poolname is the name of the scheduler pool to display on the page. It is a mandatory request parameter.