Piccolo is a framework designed to make it easy to develop efficient distributed applications.
In contrast to traditional data-centric models (such as Hadoop) which present the user a single object at a time to operate on, Piccolo exposes a global table interface which is available to all parts of the computation simulataneously. This allows users to specify programs in an intuitive manner very similar to that of writing programs for a single machine.
Piccolo includes a number of optimizations to ensure that using this table interface is not just easy, but also fast:
- To ensure locality of execution, tables are explicitly partitioned across machines. User code that interacts with the tables can specify a locality preference: this ensures that the code is executed locally with the data it is accessing.
- Not all load is created equal - often some partition of a computation will take much longer then others. Waiting idly for this task to finish wastes valuable time and resources. To address this Piccolo can migrate tasks away from busy machines to take advantage of otherwise idle workers, all while preserving the locality preferences and the correctness of the program.
- Failure Handling
- Machines failures are inevitable, and generally occur when you're at the most critical time in your computation. Piccolo makes checkpointing and restoration easy and fast, allowing for quick recovery in case of failures.
- Managing the correct synchronization and update across a distributed system can be complicated and slow. Piccolo addresses this by allowing users to defer synchronization logic to the system. Instead of explicitly locking tables in order to perform updates, users can attach accumulation functions to a table: these are used automatically by the framework to correctly combine concurrent updates to a table entry.
We are still working on a formal release of Piccolo- we're also working on improving (that is to say, creating) our documentation for it. Until then, the current code may be fetched here: piccolo.tar.gz. You can browse the current state of the code base here: source.
Piccolo was accepted to the 2010 OSDI conference! You can check out the conference version of the paper here: piccolo paper.
We gave a presentation at OSDI describing how Piccolo works and how it differs from existing systems. If you are interested it provides a good introduction to the system. You can view Russell's presentation video here.
Questions or comments? Email us! firstname.lastname@example.org
This project is partially supported by the National Science Foundation under Grant No. 1065169.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.