Real-time processing of big data has become a core operation in various areas of business, such as extracting value from real-time social network data. Big data workloads in the wild show a strong temporal variability that not only poses the risk of slow responsiveness in data analysis, but also leads to a high risk of service outage. The recent development of batch streaming systems based on the MapReduce framework is shown effective on non-overloaded systems. However, little is known on how to enhance the performance of the batch streaming systems for bursty workloads. In this paper, we propose a latency-driven data controller, Dslash, which aims to process as much data as possible, while processing these as fast as the application target latency and system capacity allow. In particular, we implement Dslash on Spark Streaming - an emerging and complex batch streaming system. Dslash features include (i) placing data in an augmented distributed memory, (ii) shedding out-of-date data, (iii) improving the processing locality of Map tasks, and (iv) delaying data processing in transient overloads. Extensive evaluations on a large number of workloads show that Dslash can ensure stable and fast responsiveness compared to vanilla Spark Streaming systems.@en

Peak loads are a challenge for streaming systems. Here we present Dslash, a latency-driven controller that keeps and processes as much data as the system resources allow in order to meet a target latency.@en

Real-time processing of big data is becoming one of the core operations in various areas, such as social networks and anomaly detection. Thanks to the rich information of the data, multiple queries can be executed to analyse the data and discover a variety of business values. It is very typical that a cluster infrastructure running for example a Spark Streaming data stream processing system would execute multiple queries simultaneously. To enable multiple queries being answered from the same data concurrently, it is important to effectively allocate the CPU-cores of the underlying infrastructure to the queries, meanwhile adhering to the latency constraints of the individual queries. In this paper, we consider the problem of allocating CPU-cores in a Spark Streaming infrastructure in the context of two types of queries, namely primary and optional, that are associated with high-and low-priority analysis, respectively. We develop a controller, iBLOC, that adjusts the block sizes of streaming jobs on the fly and the parallelism level of jobs, according to the input data rates and the query priorities. Our evaluation shows that we can achieve significant CPU-core savings from the primary query type such that multiple queries can run together without impairing their latency constraints, in comparison to a static block-sizing scheme.@en