• Title/Summary/Keyword: , Update Consistency

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A Design of Update Propagation Algorithm for Replica Consistency of Transaction (트랜잭션의 복제 일관성을 위한 갱신 전파 알고리즘 설계)

  • Lee Byung-Wook
    • Journal of Internet Computing and Services
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    • v.4 no.6
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    • pp.87-93
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    • 2003
  • Data Replication makes distributed system and database system improved in availability and performance. But it is difficult to keep strict consistency in data update. Existing algorithms keep strict consistency, but have problems of cost a great deal and delay time. It is to introduce hybrid update propagation algorithm which permits eager update for original copy and propagates lazy update for other copies. Hybrid update propagation algorithm also permits group update in ownership. This algorithm menages replica version in order to control group update consistency. Consistency and performance is improved by combining eager update and lazy update with group ownership. Simulation shows improvement of transaction throughput and response time depending on application and execution environment.

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Design of Hybrid Group Update Protocol for Replica Consistency (복제 일관성을 위한 혼합 그룹 갱신 프로토콜 설계)

  • 이병욱
    • Journal of Internet Computing and Services
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    • v.2 no.5
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    • pp.71-79
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    • 2001
  • Replication in distributed databases is to improve efficiency, availability, and autonomy, But applying the strict consistency in real systems is very difficult. In this paper, I introduce a hybrid protocol permitting group update through eager update propagation and weakening consistency through lazy update, This protocol manages replica version number for the group update consistency and generates partially ordered replica spanning tree for the serializability of lazy update transactions. It preserves weak consistency by combining synchronous and asynchronous update mechanism. Study of performance analysis for the efficiency of the protocol be included in next paper.

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Asynchronous Cache Consistency Technique (비동기적 캐쉬 일관성 유지 기법)

  • 이찬섭
    • Journal of the Korea Society of Computer and Information
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    • v.9 no.2
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    • pp.33-40
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    • 2004
  • According as client/server is generalized by development of computer performance and information communication technology, Servers uses local cache for extensibility and early response time, and reduction of limited bandwidth. Consistency of cached data need between server and client this time and much technique are proposed according to this. This Paper improved update frequency cache consistency in old. Existent consistency techniques is disadvantage that response time is late because synchronous declaration or abort step increases because delaying write intention declaration. Techniques that is proposed in this paper did to perform referring update time about object that page request or when complete update operation happens to solve these problem. Therefore, have advantage that response is fast because could run write intention declaration or update by sel_mode electively asynchronously when update operation consists and abort step decreases and clearer selection.

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Replica Update Propagation Using Demand-Based Tree for Weak Consistency in the Grid Database

  • Ge, Ruixuan;Jang, Yong-Il;Park, Soon-Young;Bae, Hae-Young
    • Journal of Korea Multimedia Society
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    • v.9 no.12
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    • pp.1542-1551
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    • 2006
  • In the Grid Database, some replicas will have more requests from the clients than others. A fast consistency algorithm has been presented to satisfy the high demand nodes in a shorter period of time. But it has poor performance in multiple regions of high demand for forming the island of locally consistent replicas. Then, a leader election method is proposed, whereas it needs much additional cost for periodic leader election, information storage, and message passing, Also, false leader can be created. In this paper, we propose a tree-based algorithm for replica update propagation. Leader replicas with high demand are considered as the roots of trees which are interconnected. All the other replicas are sorted and considered as nodes of the trees. Once an update occurs at any replica, it need be transmitted to the leader replicas first. Every node that receives the update propagates it to its children in the tree. The update propagation is optimized by cost reduction for fixed propagation schedule. And it is also flexible for the dynamic model in which the demand conditions change with time.

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Version Management Method for Consistency in the Grid Database (그리드 데이터베이스에서 일관성 유지를 위한 버전 관리 기법)

  • Shin, Soong-Sun;Jang, Yong-Il;Chung, Weon-Il;Lee, Dong-Wook;Eo, Sang-Hun;Bae, Hae-Young
    • Journal of Korea Multimedia Society
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    • v.11 no.7
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    • pp.928-939
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    • 2008
  • The grid database management system is used for large data processing, high availability and data integration by grid environment. It has a replica for processing performance and high availability in each node. The grid database has a problem of inconsistency, when the update is occurred with a coincidently frequent. To solve this problem, in this paper proposed a version management method for consistency in the grid database. Proposed version manager manages a version of each replica. The version manager keeps a consistency of update operation when is occurred at each node by using a pending queue and waiting queue. Also the node keeps a consistency using a priority queue. So, proposed method has stable and fast update propagation. The proposed method shows stable and faster update propagation than traditional method by performance evaluation.

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Update Frequency Cache Consistency for Reducing Wait Time in Mobile Computing (이동 컴퓨팅 환경에서 대기 시간을 감소시키는 갱신 빈도 캐쉬 일관성 기법)

  • Lee, Chan-Seob;Kim, Dong-Hyuk;Baek, Joo-Hyun;Choi, Eui-In
    • The KIPS Transactions:PartD
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    • v.9D no.6
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    • pp.1017-1024
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    • 2002
  • According as mobile computing environment is generalized by development of wireless networking technology and communication device, mobile host uses local cache for extensibility and early response time. and reduction of limited bandwidth. This time, between mobile host and mobile support station cache need consistency interested person of done data accordingly much techniqueses propose. Existent consistency techniques because detection based techniqueses are used mainly and broadcast periodic invalid message considering frequent disconnection. However, these techniqueses increase abort step through increase or delay of transmission message number by accuracy examination of data. Therefore, because mobile host deletes cached data, and extensity are decreased. Techniques that is proposed in this paper did to perform refering update frequency about object that page request or when complete update operation happens to solve these problem. Therefore, have advantage that response is fast because could run write intention declaration or update by update frequency electively asynchronously when update operation consists and abort step decreases. Also, improved extensity running delete or propagation electively according to update frequency about periodic invalid message gone since disconnection.

Data Update on Multi-Scale Databases (다중축척 공간 데이터베이스의 데이터 갱신)

  • Kwon O-Je;Kang Hae-Kyong;Li Ki-Joune
    • Spatial Information Research
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    • v.12 no.3
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    • pp.239-249
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    • 2004
  • This paper discusses on the update problem of multi-scale databases when the multi-scale databases, which is several spatial databases covering the same geographic area with different scales, are derived from an original one. Although the integrity between original and derived multi-scale databases should be maintained, most of update mechanisms do not 6respect it since the update mechanisms have assumed that the update of source objects propagates to objects directly derived from the source. In order to maintain the integrity of multi-scale databases during updates, we must propagate updates of sources to objects derived from both the updated source objects and other related objects. It is an important functional requirement of multi-scale database systems, which has not been supported by existing spatial database systems. In this paper, we propose a set of rules and algorithms for the update propagation and show a prototype developed on ArcGIS of ESRI. Our update mechanism provides with not only the consistency between multi-scale databases but also incremental updates.

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Update Protocol for Distributed Spatial Objects with Spatial Relationships based on OGIS OLE DB (OGIS OLE DB 기반의 공간관련성을 가진 분산 공간객체의 변경 프로토콜)

  • Kim, Dong-Hyun;Moon, Sang-Ho;Hong, Bong-Hee
    • The KIPS Transactions:PartD
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    • v.11D no.2
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    • pp.259-268
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    • 2004
  • For supporting Interoperability among heterogeneous data sources in different geographic information systems, it is required to use open API like OGIS OLE DB Proposed in OGC. The OLE/COM Implementation Specification of OGIS only provides interfaces to discover and access spatial data, but does not support interfaces for updating distributed spatial data. To solve this problem, we propose and add interfaces for updating spatial objects distributed over heterogeneous data sources and examining the consistency of spatial relationships between updated objects. We also devise a 2-phase commit protocol based on spatial relationships in order to guarantee the consistency of updated objects. To justify the update scheme using the proposed Interfaces and 2-phase commit prototype we design and implement a prototype system for updating distributed spatial objects.

Metadata Management Method for Consistency and Recency in Digital Library (디지탈 도서관 환경에서 일관성과 최근성을 고려한 메타데이타 관리 방법)

  • Lee, Hai-Min;Park, Seog
    • Journal of KIISE:Databases
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    • v.27 no.1
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    • pp.22-32
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    • 2000
  • The Digital Library is the integrated system of Information Retrieval System(IRS) and Database Management system(DBMS). In the Digital Library environment where dynamic query and update processes are required, however, the existing transaction management methods cause the following problems. First, since the traditional consistency criteria is too restrictive, it causes increment of query processing time and cannot guarantee the reflection of recency. Second, query result could be unreliable because the consistency criteria between source data and metadata is not defined. This paper models the access to metadata based on Dublin Core as query transactions and update transactions, and gives the efficient method to manage them. Particularly, this paper describes the consistency criteria of metadata which takes it Into consideration the consistency between the result of query transaction and status of source data in the Digital Library, that is different from the consistency criteria in traditional transaction management. It also presents analysis of the view point of query transaction to reflect recency and proposes metadata management to guarantee recency within metadata consistency.

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Concurrency Control and Consistency Maintenance of Cached Spatial Data in Client-Server Environment (클라이언트-서버 환경에서 캐쉬된 공간 데이터의 동시성 제어 및 일관성 유지 기법)

  • Shin, Young-Sang;Hong, Bong-Hee
    • Journal of KIISE:Databases
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    • v.28 no.3
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    • pp.512-527
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    • 2001
  • In a client-server spatial database, it is desirable to maintain the cached data in a client side to minimize the communication overhead across a network. This paper deals with the issues of concurrency and consistency of map updates in this environment. A client transaction to update map data is an interactive work and takes a long time to complete it. The map update in a client site may affect the other sites'updates because of dependencies between spatial data stored at different sites. The concurrent updates should be propagated to the other clients as well as the server to keep the consistency of map replicated in a client cache, and also the communication overhead of the update propagation should be minimized not to lose the benefit of caching. The newly proposed cache region locking with CR lock and CX lock controls the update dependency due to spatial relationships. CS lock and COD lock are suggested to use optimistic detection-based approaches for guaranteeing the consistency of cached client data. The cooperative update protocol uses these extended locking primitives and Spatial Relationship-based 2PC (SR-based 2PC). This paper argues that the concurrent updates of cached client spatial data can be achieved by deciding on collaborative updates or independent updates based on spatial relationships.

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