PISA: an Index for Aggregating Big Time Series Data

Aggregation operation plays an important role in time series database management. As the amount of data increases, current solutions such as summary table and MapReduce-based methods struggle to respond to such queries with low latency. Other approaches such as segment tree based methods have a poor insertion performance when the data size exceeds the available memory. This paper proposes a new segment tree based index called PISA, which has fast insertion performance and low latency for aggregation queries. PISA uses a forest to overcome the performance disadvantages of insertions in traditional segment trees. By de fining two kinds of tags, namely code number and serial number, we propose an algorithm to accelerate queries by avoiding reading unnecessary data on disk. The index is stored on disk and only takes a few hundred bytes of memory for billions of data points. PISA can be easily implemented on both traditional databases and NoSQL systems, examples including MySQL and Cassandra. It handles aggregation queries within milliseconds on a commodity server for a time range that may contain tens of billions of data points.