Garbage collecting the Internet

Sudi, Abdullahi; Ringwood, Graem A.

doi:10.1145/292469.292471

Cited by 37 publications

(12 citation statements)

References 77 publications

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“…The garbage collector uses a "refers-to" graph to record references between a collection of distributed objects. The objective is to detect strongly connected components that are not reachable from a distinguished "root" object; such components can safely be reclaimed [1].…”

Section: Case Studymentioning

confidence: 99%

Consistency without borders

Alvaro

Bailis

Conway

et al. 2013

Proceedings of the 4th Annual Symposium on Cloud Computing

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Distributed consistency is a perennial research topic; in recent years it has become an urgent practical matter as well. The research literature has focused on enforcing various flavors of consistency at the I/O layer, such as linearizability of read/write registers. For practitioners, strong I/O consistency is often impractical at scale, while looser forms of I/O consistency are difficult to map to application-level concerns. Instead, it is common for developers to take matters of distributed consistency into their own hands, leading to application-specific solutions that are tricky to write, test and maintain.In this paper, we agitate for the technical community to shift its attention to approaches that lie between the extremes of I/O-level and application-level consistency. We ground our discussion in early work in the area, including our own experiences building programmer tools and languages that help developers guarantee distributed consistency at the application level. Much remains to be done, and we highlight some of the challenges that we feel deserve more attention.

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Section: Case Studymentioning

confidence: 99%

Consistency without borders

Alvaro

Bailis

Conway

et al. 2013

Proceedings of the 4th Annual Symposium on Cloud Computing

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“…Many authors use the term mutator to mean a user process, which might make storage unreachable. Surveys by Cohen [1981], Wilson [1992], Jones and Lins [1996], Abdullahi and Ringwood [1998], and Detlefs [2004] discuss issues in garbage collection and include many strategies for offline or online garbage collection for volatile storage. Besides the work that the surveys cover, additional work in online garbage collection (and related maintenance) for volatile storage includes that of Sockut [1974, pp.…”

Section: Garbage Collection For Persistent Storagementioning

confidence: 99%

“…We will not survey all strategies for volatile storage; the earlier surveys [Cohen 1981;Wilson 1992;Jones and Lins 1996;Abdullahi and Ringwood 1998] describe additional strategies for volatile storage. (2) We will survey online nonpartitioned strategies for persistent storage.…”

Section: Garbage Collection For Persistent Storagementioning

confidence: 99%

Online reorganization of databases

Sockut

Iyer

2009

ACM Comput. Surv.

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In practice, any database management system sometimes needs reorganization, that is, a change in some aspect of the logical and/or physical arrangement of a database. In traditional practice, many types of reorganization have required denying access to a database (taking the database offline) during reorganization. Taking a database offline can be unacceptable for a highly available (24-hour) database, for example, a database serving electronic commerce or armed forces, or for a very large database. A solution is to reorganize online (concurrently with usage of the database, incrementally during users' activities, or interpretively). This article is a tutorial and survey on requirements, issues, and strategies for online reorganization. It analyzes the issues and then presents the strategies, which use the issues. The issues, most of which involve design trade-offs, include use of partitions, the locus of control for the process that reorganizes (a background process or users' activities), reorganization by copying to newly allocated storage (as opposed to reorganizing in place), use of differential files, references to data that has moved, performance, and activation of reorganization. The article surveys online strategies in three categories of reorganization. The first category, maintenance, involves restoring the physical arrangement of data instances without changing the database definition. This category includes restoration of clustering, reorganization of an index, rebalancing of parallel or distributed data, garbage collection for persistent storage, and cleaning (reclamation of space) in a logstructured file system. The second category involves changing the physical database definition; topics include construction of indexes, conversion between B + -trees and linear hash files, and redefinition (e.g., splitting) of partitions. The third category involves changing the logical database definition. Some examples are changing a column's data type, changing the inheritance hierarchy of object classes, and changing a relationship from one-to-many to many-to-many. The survey encompasses both research and commercial implementations, and this article points out several open research topics. As highly available or very large databases continue to become more common and more important in the world economy, the importance of online reorganization is likely to continue growing.

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“…In particular, our algorithm is a variant of a "snapshot-at-beginning" scheme. Such schemes allow garbage collection to be interleaved with ongoing programs [Wilson 1992;Abdullahi and Ringwood 1998]. Our algorithm is tailored to cope with the problems introduced by persistence and is designed to be efficiently integrated with the buffer management, concurrency control, logging, recovery, and cache consistency mechanisms of a persistent object store.…”

Section: Disk-resident Datamentioning

confidence: 99%

“…Keeping track of intersite references is similar to the problem of maintaining cross-partition references in a centralized scheme, but is more difficult in the distributed environment because of the potential for lost, duplicated, or delayed messages, individual site crashes, etc. [Abdullahi and Ringwood 1998]. …”

Section: Distributed Systemsmentioning

confidence: 99%

Garbage collection for a client-server persistent object store

Amsaleg

Franklin

Gruber

1999

ACM Trans. Comput. Syst.

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We describe an efficient server-based algorithm for garbage collecting persistent object stores in a client-server environment. The algorithm is incremental and runs concurrently with client transactions. Unlike previous algorithms, it does not hold any transactional locks on data and does not require callbacks to clients. It is fault-tolerant, but performs very little logging. The algorithm has been designed to be integrated into existing systems, and therefore it works with standard implementation techniques such as Two-Phase Locking and WriteAhead-Logging. In addition, it supports client-server performance optimizations such as client caching and flexible management of client buffers. We describe an implementation of the algorithm in the EXODUS storage manager and present the results of a performance study of the implementation.

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Garbage collecting the Internet

Cited by 37 publications

References 77 publications

Consistency without borders

Consistency without borders

Online reorganization of databases

Garbage collection for a client-server persistent object store

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