公开(公告)号：US5623670A

公开(公告)日：1997-04-22

申请号：US390179

申请日：1995-02-17

申请人： Philip L. Bohannon ,  Jacques Gava ,  Daniel F. Lieuwen ,  Sundararajarao Sudarshan

发明人： Philip L. Bohannon ,  Jacques Gava ,  Daniel F. Lieuwen ,  Sundararajarao Sudarshan

IPC分类号： G06F15/16 ,  G06F9/46 ,  G06F9/52 ,  G06F15/177 ,  G06F13/14

CPC分类号： G06F9/52

摘要： A fast crash safe method and apparatus for enforcing mutually exclusive access to shared resources in a computer system through the use of semaphores. The acquisition and release of the semaphores is implemented at the user process level. An overestimate and underestimate of semaphore ownership are maintained in memory by library provided semaphore acquisition and release code. A cleanup routine reconciles the overestimate and underestimate to determine the ownership status of the semaphores.

摘要翻译： 一种快速崩溃的安全方法和装置，用于通过使用信号量来强制互操作地访问计算机系统中的共享资源。 信号量的获取和释放在用户进程级别实现。 通过图书馆提供的信号量采集和发布代码，对信号量所有权的过高估计和低估维持在记忆体中。 清理程序调和高估和低估以确定信号量的所有权状态。

公开(公告)号：US6125371A

公开(公告)日：2000-09-26

申请号：US914744

申请日：1997-08-19

申请人： Philip L. Bohannon ,  Dennis W. Leinbaugh ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

发明人： Philip L. Bohannon ,  Dennis W. Leinbaugh ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

IPC分类号： G06F17/30

CPC分类号： G06F17/30309 ,  G06F2216/09 ,  Y10S707/99954

摘要： For use with a database of data records stored in a memory, a system and method for increasing a memory capacity and a memory database employing the system or the method. The system includes: (1) a time stamping controller that assigns a time stamp to transactions to be performed on the database, the time stamp operates to preserve an order of the transactions, (2) a versioning controller that creates multiple versions of ones of the data records affected by the transactions that are update transactions and (3) an aging controller, which is associated with each of the time stamping and versioning controllers, that monitors a measurable characteristic of the memory and deletes ones of the multiple versions of the ones of the data records in response to the time stamp and the measurable characteristic thereby to increase memory capacity.

摘要翻译： 用于存储在存储器中的数据记录的数据库，用于增加存储器容量的系统和方法以及采用该系统或方法的存储器数据库。 该系统包括：（1）时间戳控制器，为在数据库上执行的事务分配时间戳，时间戳操作以保持事务的顺序，（2）版本控制器，其创建多个版本的 由更新事务的事务影响的数据记录和（3）与每个时间戳和版本控制器相关联的老化控制器，其监视存储器的可测量特性并删除其中的一个版本 的数据记录，以响应于时间戳和可测量的特性，从而增加存储器容量。

公开(公告)号：US06374264B1

公开(公告)日：2002-04-16

申请号：US09207926

申请日：1998-12-09

申请人： Philip L. Bohannon ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

发明人： Philip L. Bohannon ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

IPC分类号： G06F1730

CPC分类号： G06F11/1474 ,  G06F11/1471 ,  G06F2201/80 ,  Y10S707/99932 ,  Y10S707/99953

摘要： A method of detecting and recovering from data corruption of a database is characterized by the step of protecting data of the database with codewords, one codeword for each region of the database; and verifying that a codeword matches associated data before the data is read from the database to prevent transaction-carried corruption. A deferred maintenance scheme is recommended for the codewords protecting the database such that the method of detecting and recovering from data corruption of a database may comprise the steps of protecting data of the database with codewords, one codeword for each region of the database; and asynchronously maintaining the codewords to improve concurrency of the database. Moreover, the database may be audited by using the codewords and noting them in a table and protecting regions of the database with latches. Once codeword values are computed and checked against noted values in memory, a flush can cause codewords from outstanding log records to be applied to the stored codeword table.

摘要翻译： 一种从数据库的数据损坏中检测和恢复的方法的特征在于利用码字保护数据库的数据的步骤，数据库的每个区域的一个码字; 并且在从数据库读取数据之前验证码字匹配相关联的数据以防止交易携带的损坏。 对于保护数据库的代码字，建议使用延迟维护方案，以便检测和恢复数据库的数据损坏的方法可以包括以下代码字来保护数据库的数据的步骤，数据库的每个区域的一个代码字; 并且异步地维护码字以改善数据库的并发性。 此外，可以通过使用码字来审核数据库，并在表中注明数据库，并用锁存器保护数据库的区域。 一旦根据存储器中的标记值计算和检查码字值，则刷新可以使来自未完成的日志记录的码字被应用于存储的码字表。

公开(公告)号：US6122645A

公开(公告)日：2000-09-19

申请号：US2635

申请日：1998-01-05

申请人： Philip L. Bohannon ,  Dennis W. Leinbaugh ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

发明人： Philip L. Bohannon ,  Dennis W. Leinbaugh ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

IPC分类号： G06F17/30

CPC分类号： G06F17/30309 ,  Y10S707/99953 ,  Y10S707/99954

摘要： For use with a database of data records organized into components, the database stored in a memory, a processing system for, and method of, physically versioning the database. In one embodiment, the processing system includes: (1) a component copier that creates a physical copy of an original component to be affected by an update transaction to be applied to the database, and that causes pointers in nodes of the physical copy to point to other nodes in the physical copy, (2) a data updater, associated with the component copier, that applies the update transaction to the physical copy to create therefrom a new physical version, the original component remaining unaffected by the update transaction and (3) a pointer updater, associated with the data updated, that employs an atomic word write to revise a component pointer, associated with the database, to cause the pointer to point to the new physical version.

摘要翻译： 为了与组织成组件的数据记录的数据库一起使用，存储在内存中的数据库，处理系统以及对数据库进行物理版本化的方法。 在一个实施例中，处理系统包括：（1）组件复印机，其创建将要被应用于数据库的更新事务影响的原始组件的物理副本，并且使物理副本的节点中的指针指向 到物理副本中的其他节点，（2）与组件复印机相关联的数据更新器，将更新事务应用于物理副本以从其创建新的物理版本，原始组件不受更新事务的影响，（3 ）与更新的数据相关联的指针更新器，其使用原子字写入来修改与数据库相关联的组件指针，以使指针指向新的物理版本。

公开(公告)号：US06449623B1

公开(公告)日：2002-09-10

申请号：US09207927

申请日：1998-12-09

申请人： Philip L. Bohannon ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

发明人： Philip L. Bohannon ,  Rajeev Rastogi ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

IPC分类号： G06F1200

CPC分类号： G06F11/1474 ,  G06F11/1471 ,  G06F2201/80 ,  Y10S707/99932 ,  Y10S707/99953

摘要： A method of detecting and recovering from data corruption of a database is characterized by the step of logging information about reads of a database in memory to detect errors in data of the database, wherein said errors in data of said database arise from one of bad writes of data to the database, of erroneous input of data to the database by users and of logical errors in code of a transaction. The read logging method may be implemented in a plurality of database recovery models including a cache-recovery model, a prior state model a redo-transaction model and a delete transaction model. In the delete transaction model, it is assumed that logical information is not available to allow a redo of transactions after a possible error and the effects of transactions that read corrupted data are deleted from history and any data written by a transaction reading Ararat data is treated as corrupted.

摘要翻译： 从数据库的数据损坏中检测和恢复的方法的特征在于记录关于数据库在存储器中的读取的信息的步骤，以检测数据库的数据中的错误，其中所述数据库的数据中的错误来自坏写入之一 的数据，数据由用户错误地输入到数据库以及事务代码中的逻辑错误。 读取记录方法可以在包括高速缓存恢复模型，先前状态模型，重做事务模型和删除事务模型的多个数据库恢复模型中实现。 在删除事务模型中，假设逻辑信息不可用于允许在可能的错误之后重做事务，并且从历史中删除读取损坏的数据的事务的影响，并且处理由读取Ararat数据的事务写入的任何数据被处理 被破坏。

公开(公告)号：US6012062A

公开(公告)日：2000-01-04

申请号：US607983

申请日：1996-03-04

申请人： Hosagrahar Visvesvaraya Jagadish ,  Ramarao Kanneganti ,  Sundararajarao Sudarshan

发明人： Hosagrahar Visvesvaraya Jagadish ,  Ramarao Kanneganti ,  Sundararajarao Sudarshan

IPC分类号： G06F12/00 ,  G06T9/00 ,  G11B20/00 ,  G11B20/10 ,  H03M7/30 ,  H03M7/40 ,  G06F17/30

CPC分类号： H03M7/3086 ,  G06T9/005 ,  G11B20/00007 ,  G11B20/10 ,  G11B2020/10916 ,  Y10S707/99942

摘要： A data base system buffers incoming records according to destination in the disk or non-volatile memory. The data is compressed and transferred to disk when sufficient data has been accumulated for a particular disk destination. Techniques for compressing the compression dictionary as well as the data stream are described.

摘要翻译： 数据库系统根据磁盘或非易失性存储器中的目的地缓存传入记录。 当为特定的磁盘目的地累积了足够的数据时，数据被压缩并传输到磁盘。 描述了用于压缩压缩字典以及数据流的技术。

公开(公告)号：US20080071785A1

公开(公告)日：2008-03-20

申请号：US11468928

申请日：2006-08-31

申请人： Govind Kabra ,  Ravishankar Ramamurthy ,  Sundararajarao Sudarshan

发明人： Govind Kabra ,  Ravishankar Ramamurthy ,  Sundararajarao Sudarshan

IPC分类号： G06F17/30

CPC分类号： G06F17/30471 ,  G06F17/30306 ,  G06F21/6227

摘要： Fine-grained access control for querying a database with low overhead and safety plans. In a view placement approach, base relations of the query expression are replaced by views that are appropriate for the particular user. Information leakage via UDF pushing, exception processing, and error messages can be prevented by generating safe plans. An existing query optimizer can be modified to perform redundancy removal and safe plan implementation. Subsumption testing available in materialized view matching can be exploited by the query optimizer. Authorization inference is exploited to generate safe plans.

摘要翻译： 用于以低开销和安全计划查询数据库的细粒度访问控制。 在视图放置方法中，查询表达式的基础关系被替换为适合特定用户的视图。 可以通过生成安全计划来防止通过UDF推送，异常处理和错误消息的信息泄漏。 可以修改现有的查询优化器，以执行冗余删除和安全计划实施。 查询优化器可以利用实体​​化视图匹配中的可用度量测试。 利用授权推理来制定安全计划。

公开(公告)号：US06363403B1

公开(公告)日：2002-03-26

申请号：US09345826

申请日：1999-06-30

申请人： Prasan Roy ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

发明人： Prasan Roy ,  Srinivasan Seshadri ,  Abraham Silberschatz ,  Sundararajarao Sudarshan

IPC分类号： G06F1730

CPC分类号： G06F12/0261 ,  G06F17/30362 ,  G06F17/30368 ,  Y10S707/99944 ,  Y10S707/99957

摘要： A reference counting a garbage collection process employs a reference counting technique in which only the “last” detected strong pointer is followed to an object. Moreover, no assumptions are made about the phase locking used in the transaction and strict WAL is not followed. Indeed, a relatively restricted local traversal of the object graph is employed which leads to higher efficiency. Furthermore, in a client-server arrangement, updates made by a transaction running at the client may be reflected at the server after the transaction ends, and the updates are not required to be forced to the server before the end of the transaction.

摘要翻译： 对垃圾收集过程进行计数的参考采用一种引用计数技术，其中只有“最后”检测到的强指针被跟随到对象。 此外，没有对事务中使用的锁相进行假设，并且不遵循严格的WAL。 实际上，采用对象图的相对受限的局部遍历，这导致更高的效率。 此外，在客户端 - 服务器安排中，在事务结束之后，在客户机上运行的事务进行的更新可以在服务器处反映，并且在事务结束之前不需要将更新强制到服务器。

公开(公告)号：US6061676A

公开(公告)日：2000-05-09

申请号：US862906

申请日：1997-05-23

申请人： Divesh Srivastava ,  Peter J. Stuckey ,  Sundararajarao Sudarshan

发明人： Divesh Srivastava ,  Peter J. Stuckey ,  Sundararajarao Sudarshan

IPC分类号： G06F17/30

CPC分类号： G06F17/30463 ,  G06F17/30454 ,  Y10S707/954 ,  Y10S707/99932 ,  Y10S707/99933 ,  Y10S707/99934 ,  Y10S707/99935

摘要： An equivalence rule having the multiset version of the relational algebraic theta-semijoin operator is used in effectuating Constraint Magic rewriting on a computer programming language query having non-equality, as well as equality, predicates. In particular, the rule effectuates Constraint Magic rewriting for a single join. When applied repeatedly on a sequence of joins, Constraint Magic rewriting is effectuated for a single block query. The rule may be used to generate relational algebraic expressions to optimize or determine the equivalency of queries. Cost estimates for alternative ways of evaluating a complex query can be efficiently computed. Based on these computed cost estimates, the least costly implementation of a complex query is determined.

摘要翻译： 具有关系代数theta-semijoin算子的多重版本的等价规则被用于在具有不相等性以及相等的谓词的计算机编程语言查询上实现约束魔法重写。 特别地，规则对单个连接实施约束魔法重写。 当对一系列连接重复应用时，对于单个块查询实现了约束魔法重写。 该规则可用于生成关系代数表达式以优化或确定查询的等价性。 可以有效地计算评估复杂查询的替代方法的成本估算。 基于这些计算的成本估计，确定复杂查询的成本最低的实现。

公开(公告)号：US6026390A

公开(公告)日：2000-02-15

申请号：US890194

申请日：1997-07-09

申请人： Kenneth A. Ross ,  Divesh Srivastava ,  Sundararajarao Sudarshan

发明人： Kenneth A. Ross ,  Divesh Srivastava ,  Sundararajarao Sudarshan

IPC分类号： G06F17/30

CPC分类号： G06F17/30383 ,  G06F17/30312 ,  Y10S707/99931 ,  Y10S707/99932 ,  Y10S707/99933 ,  Y10S707/99934 ,  Y10S707/99935 ,  Y10S707/99936 ,  Y10S707/99937

摘要： A method of incrementally maintaining a first materialized view of data in a database, by means of an additional materialized view, first determines whether a cost in time of incrementally maintaining the first materialized view with the additional materialized view is less than the cost of incrementally maintaining the first materialized view without the additional materialized view. The method creates the additional materialized view only if the cost in time is less therewith. Determining whether the cost of employing an additional materialized view is less includes using an expression directed acyclic graph that corresponds to the first materialized view. Another method of determining whether the cost is less includes pruning an expression directed acyclic graph to produce a single expression tree, and using the single expression tree to determine whether the cost is less. Both the expression directed acyclic graph and the single expression tree contain equivalence nodes. One or more possible materialized views are selected by marking the equivalence nodes, and materializing one or more views corresponding to the marked equivalence nodes. One or more possible materialized views are also selected by determining which of the views, if materialized, would result in a lowest cost of incrementally maintaining the first materialized view. The method is also used to reduce the cost in time of maintaining a first materialized view employed to check an integrity constraint of the database.

摘要翻译： 通过附加的物化视图来逐步维护数据库中的数据的第一物化视图的方法首先确定用附加物化视图逐步维持第一物化视图的时间成本是否小于增量维护的成本 第一个物化视图没有附加的物化视图。 该方法只有在时间上的成本较低时才创建附加的物化视图。 确定采用附加物化视图的成本是否较小包括使用对应于第一实例化视图的表达式有向无环图。 确定成本是否较小的另一种方法包括修剪表达式非循环图以产生单个表达式树，并使用单个表达式树来确定成本是否较小。 表达式非循环图和单个表达式树都包含等价节点。 通过标记等价节点以及实现对应于标记的等价节点的一个或多个视图来选择一个或多个可能的物化视图。 还可以通过确定哪些视图（如果实现）将导致递增地维持第一实例化视图的最低成本来选择一个或多个可能的物化视图。 该方法还用于降低维护用于检查数据库的完整性约束的第一物化视图的时间成本。