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    • 1. 发明授权
    • Parallel queue propagation
    • 并行队列传播
    • US5870761A
    • 1999-02-09
    • US770573
    • 1996-12-19
    • Alan DemersJames StamosSandeep JainBrian OkiRoger J. Bamford
    • Alan DemersJames StamosSandeep JainBrian OkiRoger J. Bamford
    • G06F17/30
    • G06F17/30581Y10S707/99931Y10S707/99932Y10S707/99937Y10S707/99938Y10S707/99942Y10S707/99952Y10S707/99953
    • A method and system are provided for duplicating at a destination site changes made to data at a source site. According to the method a plurality of streams are established between the source site and the destination site. The plurality of streams are used in parallel to propagate changes made at the source site to the destination site. A record of transactions that made changes that need to be propagated from the source site to the destination site is maintained at the source site. Before propagating changes made by a transaction to the destination site on a stream of the plurality of streams, the record of transactions is inspected to identify a set of transactions whose changes are not known to have been made permanent at the destination site. It is then determined whether the transaction could possibly depend on any transaction in the set of transactions. If the transaction could not possibly depend on any transaction in the set of transactions, then the changes made by the transaction are propagated to the destination site using one of the plurality of streams.
    • 提供了一种方法和系统,用于在目的地站点复制源站点上的数据。 根据该方法,在源站点和目的站点之间建立多个流。 多个流并行使用,以将源站点处的更改传播到目标站点。 源站点上保留了需要从源站点传播到目标站点的更改事务记录。 在将交易所做的改变传播到多个流的流之前的目的地站点之前,检查事务的记录以识别一组事务,其变化不知道已经在目的地站点被永久化。 然后确定交易是否可能依赖于该组交易中的任何交易。 如果事务不可能依赖于事务集合中的任何事务,则事务所做的更改使用多个流中的一个传播到目标站点。
    • 4. 发明授权
    • Method and apparatus for transferring data from the cache of one node to the cache of another node
    • 用于将数据从一个节点的高速缓存传送到另一个节点的高速缓存的方法和装置
    • US06353836B1
    • 2002-03-05
    • US09199120
    • 1998-11-24
    • Roger J. BamfordBoris Klots
    • Roger J. BamfordBoris Klots
    • G06F1730
    • G06F11/1471G06F2201/80Y10S707/915Y10S707/99938Y10S707/99952Y10S707/99953Y10S707/99954
    • A method and apparatus are provided for transferring a resource from the cache of one database server to the cache of another database server without first writing the resource to disk. When a database server (Requestor) desires to modify a resource, the Requestor asks for the current version of the resource. The database server that has the current version (Holder) directly ships the current version to the Requestor. Upon shipping the version, the Holder loses permission to modify the resource, but continues to retain the resource in memory. When the retained version of the resource, or a later version thereof, is written to disk, the Holder can discard the retained version of the resource. Otherwise, the Holder does not discard the retained version. Using this technique, single-server failures are recovered without having to merge the recovery logs of the various database servers that had access to the resource.
    • 提供了一种方法和装置,用于将资源从一个数据库服务器的高速缓存传送到另一个数据库服务器的高速缓存,而无需首先将资源写入磁盘。 当数据库服务器(请求者)希望修改资源时,请求者要求资源的当前版本。 具有当前版本(Holder)的数据库服务器将当前版本直接发送到请求者。 运送版本后,持有人将失去修改资源的权限,但继续将资源保留在内存中。 当将资源的保留版本或其更新版本写入磁盘时,持有者可以丢弃资源的保留版本。 否则,持有人不会丢弃保留的版本。 使用此技术,恢复单服务器故障,而无需合并可访问资源的各种数据库服务器的恢复日志。
    • 7. 发明授权
    • Tracking dependencies between transactions in a database
    • 跟踪数据库中的事务之间的依赖关系
    • US5806076A
    • 1998-09-08
    • US740544
    • 1996-10-29
    • Gary C. NgaiRoger J. BamfordGarret Swart
    • Gary C. NgaiRoger J. BamfordGarret Swart
    • G06F9/46G06F17/30
    • G06F17/30356G06F9/466Y10S707/99953Y10S707/99954
    • A method and an apparatus for tracking of the dependencies between transactions is provided. Every time a data item is updated, a record is made of the transaction that updated the data item. Before another transaction locks a data item previously locked by the transaction, the entry is updated to indicate that the transaction committed and the commit time of the transaction. These entries are contained in a list head that is maintained on the same block as the data item, and a list tail that is stored separate from the data block that contains the data item. A depends-on time is maintained for each transaction. Whenever the transaction updates a data item, the depends-on time is set to the greater of the current depends-on time and the commit time of the most recently committed transaction that updated the version of the data item. Whether a transaction depends on a committed transaction is then determined based on a simple comparison between the depends-on time associated with the transaction and the commit time of the committed transaction.
    • 提供了用于跟踪事务之间的依赖关系的方法和装置。 每次更新数据项时,都会对更新数据项的事务进行记录。 在另一个事务锁定先前由事务锁定的数据项之前,将更新该条目以指示事务已提交和事务的提交时间。 这些条目包含在与数据项相同的块上维护的列表头中,以及与包含数据项的数据块分开存储的列表尾。 维护每个交易的依赖时间。 每当事务更新数据项时,依赖时间被设置为当前依赖时间的更大值以及更新数据项版本的最近提交的事务的提交时间。 然后,基于与事务相关联的依赖时间与承诺事务的提交时间之间的简单比较来确定事务是否依赖于提交的事务。
    • 8. 发明授权
    • Semantic response to lock requests to reduce coherence overhead in multi-node systems
    • 语义响应锁定请求以减少多节点系统中的一致性开销
    • US08086579B1
    • 2011-12-27
    • US10056716
    • 2002-01-22
    • Sashikanth ChandrasekaranRoger J. Bamford
    • Sashikanth ChandrasekaranRoger J. Bamford
    • G06F7/00G06F17/00G06F17/30
    • G06F17/30362
    • Techniques are provided for lock management. The techniques are based on an enhanced lock management system that generates a semantic response in response to lock requests for a resource. The semantic response communicates both the underlying cause blocking the request, and information that may be used by the requester to obtain notification of when the underlying cause should no longer lead to denial of the lock request. The semantic response may be generated by the master of the resource, who provides the semantic response to the local lock manager of the lock requester. The semantic response may be retained by the local lock manager so that the semantic response can be provided to subsequent lock requesters, without need for interacting with another lock manager on another node.
    • 提供了锁管理技术。 这些技术基于增强的锁管理系统,其响应于对资源的锁请求而产生语义响应。 语义响应传达阻止请求的基本原因以及请求者可以使用的信息,以获得何时不再导致拒绝锁定请求的通知。 语义响应可以由资源的主人产生,该资源的主人向锁请求者的本地锁管理器提供语义响应。 语义响应可以由本地锁管理器保留,使得可以将语义响应提供给后续的锁请求者,而不需要与另一节点上的另一个锁管理器进行交互。
    • 10. 发明授权
    • One-phase commit in a shared-nothing database system
    • 无共享数据库系统中的一阶段提交
    • US06845384B2
    • 2005-01-18
    • US10718875
    • 2003-11-21
    • Roger J. BamfordSashikanth ChandrasekaranAngelo Pruscino
    • Roger J. BamfordSashikanth ChandrasekaranAngelo Pruscino
    • G06F9/50G06F17/30
    • G06F17/30575G06F17/30377Y10S707/99956
    • Techniques are provided for handling distributed transactions in shared-nothing database systems where one or more of the nodes have access to a shared persistent storage. Rather than coordinate the distributed transaction using a two-phase commit protocol, the coordinator of the distributed transaction uses a one-phase commit protocol with those participants that have access to the transaction status information maintained by the coordinator. The transaction status information may reside, for example, in the redo log of the coordinator. In the case that the coordinator fails, those participants can determine the state of the distributed transaction based on information stored on the shared disk. In addition, the coordinator is able to determine whether it is possible to commit the distributed transaction based on information that is stored on the shared disk by the participants, without those participants entering a formal “prepared” state.
    • 提供了用于在无共享数据库系统中处理分布式事务的技术,其中一个或多个节点可以访问共享永久存储。 分布式事务的协调器不是使用两阶段提交协议来协调分布式事务,而是与那些能够访问协调器维护的事务状态信息的参与者使用一阶段提交协议。 事务状态信息可以驻留在例如协调器的重做日志中。 在协调器失败的情况下,这些参与者可以基于存储在共享磁盘上的信息来确定分布式事务的状态。 此外,协调器能够根据参与者在共享磁盘上存储的信息来确定是否可以提交分布式事务,而不需要参与者进入正式的“准备”状态。