Migration Guide: Spark Core

Upgrading from Core 2.4 to 3.0

In Spark 3.0, deprecated method TaskContext.isRunningLocally has been removed. Local execution was removed and it always has returned false.
In Spark 3.0, deprecated method shuffleBytesWritten, shuffleWriteTime and shuffleRecordsWritten in ShuffleWriteMetrics have been removed. Instead, use bytesWritten, writeTime and recordsWritten respectively.
In Spark 3.0, deprecated method AccumulableInfo.apply have been removed because creating AccumulableInfo is disallowed.
In Spark 3.0, event log file will be written as UTF-8 encoding, and Spark History Server will replay event log files as UTF-8 encoding. Previously Spark writes event log file as default charset of driver JVM process, so Spark History Server of Spark 2.x is needed to read the old event log files in case of incompatible encoding.