995 research outputs found
Benchmarking Distributed Stream Data Processing Systems
The need for scalable and efficient stream analysis has led to the
development of many open-source streaming data processing systems (SDPSs) with
highly diverging capabilities and performance characteristics. While first
initiatives try to compare the systems for simple workloads, there is a clear
gap of detailed analyses of the systems' performance characteristics. In this
paper, we propose a framework for benchmarking distributed stream processing
engines. We use our suite to evaluate the performance of three widely used
SDPSs in detail, namely Apache Storm, Apache Spark, and Apache Flink. Our
evaluation focuses in particular on measuring the throughput and latency of
windowed operations, which are the basic type of operations in stream
analytics. For this benchmark, we design workloads based on real-life,
industrial use-cases inspired by the online gaming industry. The contribution
of our work is threefold. First, we give a definition of latency and throughput
for stateful operators. Second, we carefully separate the system under test and
driver, in order to correctly represent the open world model of typical stream
processing deployments and can, therefore, measure system performance under
realistic conditions. Third, we build the first benchmarking framework to
define and test the sustainable performance of streaming systems.
Our detailed evaluation highlights the individual characteristics and
use-cases of each system.Comment: Published at ICDE 201
Knowledge-infused and Consistent Complex Event Processing over Real-time and Persistent Streams
Emerging applications in Internet of Things (IoT) and Cyber-Physical Systems
(CPS) present novel challenges to Big Data platforms for performing online
analytics. Ubiquitous sensors from IoT deployments are able to generate data
streams at high velocity, that include information from a variety of domains,
and accumulate to large volumes on disk. Complex Event Processing (CEP) is
recognized as an important real-time computing paradigm for analyzing
continuous data streams. However, existing work on CEP is largely limited to
relational query processing, exposing two distinctive gaps for query
specification and execution: (1) infusing the relational query model with
higher level knowledge semantics, and (2) seamless query evaluation across
temporal spaces that span past, present and future events. These allow
accessible analytics over data streams having properties from different
disciplines, and help span the velocity (real-time) and volume (persistent)
dimensions. In this article, we introduce a Knowledge-infused CEP (X-CEP)
framework that provides domain-aware knowledge query constructs along with
temporal operators that allow end-to-end queries to span across real-time and
persistent streams. We translate this query model to efficient query execution
over online and offline data streams, proposing several optimizations to
mitigate the overheads introduced by evaluating semantic predicates and in
accessing high-volume historic data streams. The proposed X-CEP query model and
execution approaches are implemented in our prototype semantic CEP engine,
SCEPter. We validate our query model using domain-aware CEP queries from a
real-world Smart Power Grid application, and experimentally analyze the
benefits of our optimizations for executing these queries, using event streams
from a campus-microgrid IoT deployment.Comment: 34 pages, 16 figures, accepted in Future Generation Computer Systems,
October 27, 201
Parallel Continuous Preference Queries over Out-of-Order and Bursty Data Streams
Techniques to handle traffic bursts and out-of-order arrivals are of paramount importance to provide real-time sensor data analytics in domains like traffic surveillance, transportation management, healthcare and security applications. In these systems the amount of raw data coming from sensors must be analyzed by continuous queries that extract value-added information used to make informed decisions in real-time. To perform this task with timing constraints, parallelism must be exploited in the query execution in order to enable the real-time processing on parallel architectures. In this paper we focus on continuous preference queries, a representative class of continuous queries for decision making, and we propose a parallel query model targeting the efficient processing over out-of-order and bursty data streams. We study how to integrate punctuation mechanisms in order to enable out-of-order processing. Then, we present advanced scheduling strategies targeting scenarios with different burstiness levels, parameterized using the index of dispersion quantity. Extensive experiments have been performed using synthetic datasets and real-world data streams obtained from an existing real-time locating system. The experimental evaluation demonstrates the efficiency of our parallel solution and its effectiveness in handling the out-of-orderness degrees and burstiness levels of real-world applications
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