  Many of the existing sentiment analysis techniques are based on supervised
learning, and they demand the availability of valuable training datasets to
train their models. When dataset freshness is critical, the annotating of high
speed unlabelled data streams becomes critical but remains an open problem. In
this paper, we propose PLStream, a novel Apache Flink-based framework for fast
polarity labelling of massive data streams, like Twitter tweets or online
product reviews. We address the associated implementation challenges and
propose a list of techniques including both algorithmic improvements and system
optimizations. A thorough empirical validation with two real-world workloads
demonstrates that PLStream is able to generate high quality labels (almost 80%
accuracy) in the presence of high-speed continuous unlabelled data streams
(almost 16,000 tuples/sec) without any manual efforts.
