Presto is an open source distributed query engine that supports much of the SQL analytics workload at Facebook. Presto is designed to be adaptive, flexible, and extensible. It supports a wide variety of use cases with diverse characteristics. These range from user-facing reporting applications with sub-second latency requirements to multi-hour ETL jobs that aggregate or join terabytes of data. Presto's Connector API allows plugins to provide a high performance I/O interface to dozens of data sources, including Hadoop data warehouses, RDBMSs, NoSQL systems, and stream processing systems. In this paper, we outline a selection of use cases that Presto supports at Facebook. We then describe its architecture and implementation, and call out features and performance optimizations that enable it to support these use cases. Finally, we present performance results that demonstrate the impact of our main design decisions.

Twitter is a popular micro-blogging website which allows users to post 140-character limit messages called tweets. We demonstrate a cheap and elegant solution - WhACKY! - to harness the multi-source information from tweets to link Twitter profiles across other external services. In particular, we exploit activity feed sharing patterns to map Twitter profiles to their corresponding external service accounts using publicly available APIs. We illustrate a proof-of-concept by mapping 69,496 Twitter profiles to at least one of the five popular external services : Flickr (photo-sharing service), Foursquare (location-based service), YouTube (video-sharing service), Facebook (a popular social network) and LastFM (music-sharing service). We evaluate our solution against a commercial social identity mapping service - FlipTop - and demonstrate the efficiency of our approach. WhACKY! guarantees that the mapped profiles are 100% true-positive and helps quantify the unintended leakage of Personally Identifiable Information (PII) attributes. During the process, WhACKY! is also able to detect duplicate Twitter profiles connected to multiple external services.We also develop a web application based on WhACKY!1 for perusal by Twitterers which can help them better understand unintended leakage of their PII.