It is shown that the fragment and replicate (FR) distributed join algorithm is a special case of the symmetric fragment and replicate (SFR) algorithm, which improves the FR algorithm by reducing its communication. The SFR algorithm, like the FR algorithm, is applicable to N-way joins and nonequijoins and does tuple balancing automatically. The authors derive formulae that show how to minimize the communication in the SFR algorithm, discuss its performance on a parallel database prototype, and evaluate its practicality under various conditions. It is claimed that SFR improves the worst-case cost for a distributed join, but it will not displace specialized distributed join algorithms when the later are applicable.>

The proposed coordinator log transaction execution protocol centralizes logging on a per-transaction basis and exploits piggybacking to provide the semantics of a distributed atomic commit without the associated costs. This protocol eliminates two rounds of messages (one phase) from the presumed commit protocol and dramatically reduces the number of log forces needed for distributed atomic commit. The authors compare the coordinator log transaction execution protocol with existing protocols, describe when it is desirable, and discuss how it affects the write-ahead log protocol and the database crash recovery algorithm.>

A new technique for computer-to-computer communication is presented that can increase the performance of distributed systems. This technique, called remote evaluation, lets one computer send another computer a request in the form of a program. A computer that receives such a request executes the program in the request and returns the results to the sending computer. Remote evaluation provides a new degree of flexibility in the design of distributed systems. In present distributed systems that use remote procedure calls, server computers are designed to offer a fixed set of services. In a system that uses remote evaluation, server computers are more properly viewed as programmable processors. One consequence of this flexibility is that remote evaluation can reduce the amount of communication that is required to accomplish a given task. In this paper we discuss the semantics of remote evaluation and its effect on distributed system design. We also summarize our experience with a prototype implementation.

Remote evaluation (REV) is a construct for building distributed systems that involves sending executable code from one computer to another computer via a communication network. How REV can reduce communication and improve performance for certain classes of distributed applications is explained. Implementation issues are discussed. REV is incorporated into a high-level programming language by defining its syntax and its semantics. The compile-time and run-time support for REV is discussed in both heterogeneous and homogeneous systems and compared to that needed by a remote procedure call implementation. Sample performance measurements are included. Experience with a prototype REV implementation is summarized.>

Smalltalk is an object-oriented, interactive programming environment that maintains state between user sessions.Because of the persistence of objects, it is possible to use program restructuring techniques to statically relocate objects in virtual memory.Grouping related objects on the same disk page increases locality of reference, reduces the number of page faults, and improves performance.Five types of static grouping algorithms along with the static analysis performed on their outputs, and empirical evidence of their performance, are presented.