Accelerating Spark Datasets by Inlining Deserialization

Apache Spark is a framework for distributed computing that supports the map-reduce programming model. The SQL module of Spark contains Datasets, i.e., distributed collections of records stored in a serialized low-level format in a manually managed chunk of memory. However, the functions users provide to the map-reduce computations expect Java objects. Datasets perform an additional deserialization step beforehand to support the user-provided function, which increases the overhead. We tackled this problem by replacing map functions with their counterparts that accepted the serialized data. This allowed us to skip the unnecessary part of deserialization and achieve faster data processing speeds.