A Tool for Statistical Analysis on Network Big Data

Abstract

Due to advances in parallel file systems for big data (i.e. HDFS) and larger capacity hardware (multicore CPUs, large RAM) it is now feasible to manage and query network data in a parallel DBMS supporting SQL, but performing statistical analysis remains a challenge.On the statistics side, the R language is popular, but it presents important limitations: R is limited by main memory, R works in a different address space from query processing, R cannot analyze large disk-resident data sets efficiently, and R has no data management capabilities. Moreover, some R libraries allow R to work in parallel, but without data management capabilities. Considering the challenges and limitations described above, we present a system that allows combining SQL queries and R functions in a seamless manner. We justify a parallel DBMS and the R runtime are two different systems that benefit from a low-level integration. Our parallel DBMS is built on top of HDFS, programmed in Java and C++, with a flexible scale out architecture, whereas R is programmed purely in C. The user or developer can make calls in both directions: (1) R calling SQL, to evaluate analytic queries or retrieve data from materialized views (transferring result tables in RAM in a streaming fashion and analyzing them in R), and vice-versa (2) SQL calling R, allowing SQL to convert relational tables to matrices or vectors and making complex computations on them. We give a summary of network monitoring tasks at ATT and present specific programming examples, showing language calls in both directions (i.e. R calls SQL, SQL calls R).