Search for: All records

Big data systems have evolved beyond scalable storage and rudimentary processing to supporting complex data analytics in near real-time, such as Apache Spark Streaming [31], Comet [14], Incremental Hadoop [17], MapReduce Online [7], Apache Storm [28], StreamScope [19], and IBM Streams [1]. These systems are particularly challenging to build owing to two requirements: low latency and fault tolerance. Many of the above systems evolved from a batch processing design and are thus architected to break down a steady stream of input events into a series of micro-batches and then perform batch-like computations on each successive micro-batch as a micro-batch job. In terms of latency, the systems are expected to respond to each micro-batch in seconds with an output The constant operation further entails that the systems must be robust to hardware, software and network-level failures. To incorporate fault-tolerance, the common approach is to use checkpointing and rollback recovery, whereby a streaming application periodically saves its in-memory state to persistent storage.