Spark: "Truncated the string representation of a plan since it was too large." Warning when using manually created aggregation expression

You can safely ignore it, if you are not interested in seeing the sql schema logs. Otherwise, you might want to set the property to a higher value, but it might affect the performance of your job:

spark.debug.maxToStringFields=100

Default value is: DEFAULT_MAX_TO_STRING_FIELDS = 25

The performance overhead of creating and logging strings for wide schemas can be large. To limit the impact, we bound the number of fields to include by default. This can be overridden by setting the 'spark.debug.maxToStringFields' conf in SparkEnv.

Taken from: https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/util/Utils.scala#L90

This config, along many others, has been moved to: SQLConf - sql/catalyst/src/main/scala/org/apache/spark/sql/internal/SQLConf.scala

This can be set either in the config file or via command line in spark, using:

spark.conf.set("spark.sql.debug.maxToStringFields", 1000)