Incrementalization across object abstraction

Abstract

Object abstraction supports the separation of what operations are provided by systems and components from how the operations are implemented, and is essential in enabling the construction of complex systems from components. Unfortunately, clear and modular implementations have poor performance when expensive query operations are repeated, while efficient implementations that incrementally maintain these query results are much more difficult to develop and to understand, because the code blows up significantly, and is no longer clear or modular.This paper describes a powerful and systematic method that first allows the "what" of each component to be specified in a clear and modular fashion and implemented straightforwardly in an object-oriented language; then analyzes the queries and updates, across object abstraction, in the straightforward implementation; and finally derives the sophisticated and efficient "how" of each component by incrementally maintaining the results of repeated expensive queries with respect to updates to their parameters. Our implementation and experimental results for example applications in query optimization, role-based access control, etc. demonstrate the effectiveness and benefit of the method.

Algorithm Diversity for Resilient Systems

“…The two conditions in await are key to the algorithm to ensure mutual exclusion, while the rest does basic sending and receiving of messages and bookkeeping of q. [27,22,26,24]. It can yield diverse algorithms.…”

“…A more general automated approach is to generate them by starting with a high-level algorithm (or specification) and applying different optimizations (algorithm improvements, automated using program analysis and transformation). In particular, we have used a method based on systematic incrementalization [27,22,19,18], which transforms programs to maintain high-level invariants incrementally, and related optimizations to generate multiple variants of many sequential algorithms and distributed algorithms [26,25,24]. Algorithm diversity and implementation-level diversity introduce different kinds of variation and together offer more diversity than either alone.…”

Demand-driven incremental object queries

“…Liu et al [27] studies incrementalization for object-oriented programs. It transforms expensive queries and updates by applying manually written incrementalization rules from a library of rules.…”

From clarity to efficiency for distributed algorithms

“…Once these are established, updates can be determined using previously studied analysis methods, e.g., [33,51].…”

“…Incremental computation. Given expensive queries and updates to the query parameters, efficient incremental computations can be derived for large classes of queries and updates based on the language constructs used in them or by using a library of rules built on existing data structures [51,53,54,65]. For aggregations converted from quantifications, algebraic properties of the aggregation operators are exploited to efficiently handle possible updates.…”