A study of Erlang ETS table implementations and performance

The viability of implementing an in-memory database, Erlang ETS, using a relatively-new data structure, called a Judy array, was studied by comparing the performance of ETS tables based on four data structures: AVL balanced binary trees, B-trees, resizable linear hash tables, and Judy arrays. The benchmarks used workloads of sequentially- and randomly-ordered keys at table populations from 700 keys to 54 million keys

The Cyclic News Filesystem: Getting INN To Do More With Less

When Usenet News servers were first implemented, the design principle of storing each Usenet article in a separate file appeared to be sound. However, the number of Usenet News articles posted per day has grown phenomenally in the past decade and shows no sign of abating. To stay ahead of the growth curve, Usenet administrators have been forced to buy faster machines, more RAM, and many more disk drives. Many of the performance limitations are caused by interactions with the underlying OS's filesystem, which is usually a Berkeley Fast Filesystem (FFS) derivative. The Cyclic News Filesystem (CNFS) was designed to avoid most of FFS's major problems when used with INN: synchronous file linking/unlinking and sequential scanning of directory files. Articles are stored within a relative handful of large files, either as regular files on top of a standard filesystem or as block disk devices. Articles are stored sequentially within each file, resuming at the beginning of the file when the end ..

Sendmail Meets Erlang: Experiences Using Erlang for Email Applications

Our software engineering team needed to create a system that moves data from a set of legacy applications with diverse properties to data repositories scattered around the network. This system had to be highly concurrent, straightforward to extend, have high performance, and be coded rapidly by a small development staff. Because of these requirements, the authors embarked upon an experiment to write this application in Erlang. This paper describes what we did, why we did it, and what we learned over the course of our development effort. It is our hope that this chronicle may be useful to others thinking about coding in Erlang for the first time and to the incumbent Erlang community to hear an outsider's perspective on this fine language