Package org.apache.spark.sql

Class Observation

Object
org.apache.spark.sql.ObservationBase
org.apache.spark.sql.Observation
public class Observation extends ObservationBase
Helper class to simplify usage of Dataset.observe(String, Column, Column*): 


   // Observe row count (rows) and highest id (maxid) in the Dataset while writing it
   val observation = Observation("my metrics")
   val observed_ds = ds.observe(observation, count(lit(1)).as("rows"), max($"id").as("maxid"))
   observed_ds.write.parquet("ds.parquet")
   val metrics = observation.get

This collects the metrics while the first action is executed on the observed dataset. Subsequent actions do not modify the metrics returned by ObservationBase.get(). Retrieval of the metric via ObservationBase.get() blocks until the first action has finished and metrics become available.

This class does not support streaming datasets.

param: name name of the metric

Since:
3.3.0

  • Constructor Details

    • Observation

      public Observation(String name)

    • Observation

      public Observation()
      Create an Observation instance without providing a name. This generates a random name.

  • Method Details

    • apply

      public static Observation apply()
      Observation constructor for creating an anonymous observation.
      Returns:
      (undocumented)

    • apply

      public static Observation apply(String name)
      Observation constructor for creating a named observation.
      Parameters:
      name - (undocumented)
      Returns:
      (undocumented)