myList = {'Food Items': [1000, 2000, 5000],'Transportation':[500, 700, 100], 'House Rent': [2000, 3000, 4000], 'Utilities': [100, 200, 300], 'Entertainment': [500 ...

Data Skew → Uneven data distribution causes slow tasks and ... Slow UDFs → Spark UDFs (especially Python) are slower and not optimized by Catalyst. What is difference between reduceByKey & groupByKey?