Upgrading from PySpark 2.4 to 3.0

  • In Spark 3.0, PySpark requires a pandas version of 0.23.2 or higher to use pandas related functionality, such as toPandas, createDataFrame from pandas DataFrame, and so on.

  • In Spark 3.0, PySpark requires a PyArrow version of 0.12.1 or higher to use PyArrow related functionality, such as pandas_udf, toPandas and createDataFrame with “spark.sql.execution.arrow.enabled=true”, etc.

  • In PySpark, when creating a SparkSession with SparkSession.builder.getOrCreate(), if there is an existing SparkContext, the builder was trying to update the SparkConf of the existing SparkContext with configurations specified to the builder, but the SparkContext is shared by all SparkSession s, so we should not update them. In 3.0, the builder comes to not update the configurations. This is the same behavior as Java/Scala API in 2.3 and above. If you want to update them, you need to update them prior to creating a SparkSession.

  • In PySpark, when Arrow optimization is enabled, if Arrow version is higher than 0.11.0, Arrow can perform safe type conversion when converting pandas.Series to an Arrow array during serialization. Arrow raises errors when detecting unsafe type conversions like overflow. You enable it by setting spark.sql.execution.pandas.convertToArrowArraySafely to true. The default setting is false. PySpark behavior for Arrow versions is illustrated in the following table:

    PyArrow version

    Integer overflow

    Floating point truncation

    0.11.0 and below

    Raise error

    Silently allows

    > 0.11.0, arrowSafeTypeConversion=false

    Silent overflow

    Silently allows

    > 0.11.0, arrowSafeTypeConversion=true

    Raise error

    Raise error

  • In Spark 3.0, createDataFrame(..., verifySchema=True) validates LongType as well in PySpark. Previously, LongType was not verified and resulted in None in case the value overflows. To restore this behavior, verifySchema can be set to False to disable the validation.

  • As of Spark 3.0, Row field names are no longer sorted alphabetically when constructing with named arguments for Python versions 3.6 and above, and the order of fields will match that as entered. To enable sorted fields by default, as in Spark 2.4, set the environment variable PYSPARK_ROW_FIELD_SORTING_ENABLED to true for both executors and driver - this environment variable must be consistent on all executors and driver; otherwise, it may cause failures or incorrect answers. For Python versions less than 3.6, the field names will be sorted alphabetically as the only option.

  • In Spark 3.0, pyspark.ml.param.shared.Has* mixins do not provide any set*(self, value) setter methods anymore, use the respective self.set(self.*, value) instead. See SPARK-29093 for details.