Lost write detection and repair
    1.
    发明授权
    Lost write detection and repair 有权
    丢失写检测和修复

    公开(公告)号:US07627614B2

    公开(公告)日:2009-12-01

    申请号:US11072111

    申请日:2005-03-03

    IPC分类号: G06F17/30

    摘要: Techniques are provided for detecting lost writes so that data corruption can be avoided. According to one technique, lost writes are detected by comparing version numbers that are indicated in redo log entries with version numbers that are indicated in corresponding blocks in a standby database. According to one technique, which may be used in conjunction with the above technique, lost writes are detected by logging read operations that occur relative to a primary database, and comparing version numbers that are indicated in read log entries with version numbers that are indicated in corresponding blocks in a standby database. According to one technique, lost writes are detected by comparing, in response to read operations, (a) version numbers that are stored in a persistent in-memory cache with (b) version numbers that are indicated in corresponding blocks that are read from a primary database.

    摘要翻译: 提供了用于检测丢失写入的技术,从而可以避免数据损坏。 根据一种技术,通过将重做日志条目中指示的版本号与在备用数据库中的相应块中指示的版本号进行比较来检测丢失的写入。 根据可以与上述技术结合使用的一种技术,通过记录相对于主数据库发生的读取操作来检测丢失的写入,并且将读取日志条目中指示的版本号与在 备用数据库中的相应块。 根据一种技术,通过比较读取操作来检测丢失的写入,(a)存储在持久性内存高速缓存中的版本号,(b)版本号,其在从 主数据库。

    Method and mechanism for efficient implementation of ordered records
    2.
    发明授权
    Method and mechanism for efficient implementation of ordered records 有权
    有效执行有序记录的方法和机制

    公开(公告)号:US07039773B2

    公开(公告)日:2006-05-02

    申请号:US10426471

    申请日:2003-04-29

    IPC分类号: G06F12/00

    摘要: An improved method, mechanism, and system for implementing, generating, and maintaining records, such as redo records and redo logs in a database system, are disclosed. Multiple sets of records may be created and combined into a partially ordered (or non-ordered) group of records, which are later collectively ordered or sorted as needed to create an fully ordered set of records. With respect to a database system, redo generation bottleneck is minimized by providing multiple in-memory redo buffers that are available to hold redo records generated by multiple threads of execution. When the in-memory redo buffers are written to a persistent storage medium, no specific ordering needs to be specified with respect to the redo records from the different in-memory redo buffers. While the collective group of records may not be ordered, the written-out redo records may be partially ordered based upon the ordered redo records from within individual in-memory redo buffers. At recovery, ordering and/or merging of redo records may occur to satisfy database consistency requirements.

    摘要翻译: 公开了一种用于在数据库系统中实现,生成和维护记录(如重做记录和重做日志)的改进方法,机制和系统。 可以创建多组记录,并将其组合成部分有序(或非有序)的记录组,这些记录集合随后根据需要进行统一排序或排序以创建完全有序的记录集。 对于数据库系统,通过提供多个可用于保存由多个执行线程生成的重做记录的内存中重做缓冲区,可以使重做生成瓶颈最小化。 当内存中重做缓冲区被写入持久存储介质时,不需要针对来自不同内存中重做缓冲区的重做记录指定特定顺序。 虽然可能不会对集体记录进行排序,但是写出的重做记录可能会根据内部存储器重做缓冲区内的重做记录进行部分排序。 在恢复时,可能会发生重做记录的排序和/或合并,以满足数据库一致性要求。

    Enhancements to data integrity verification mechanism
    4.
    发明授权
    Enhancements to data integrity verification mechanism 有权
    增强数据完整性验证机制

    公开(公告)号:US07246281B2

    公开(公告)日:2007-07-17

    申请号:US11386495

    申请日:2006-03-21

    IPC分类号: G11C29/00 G06F12/00 G06F9/26

    摘要: A method and apparatus is provided for maintaining data integrity. According to the method, a physical checksum calculation is performed on a block of data. After performing the physical checksum calculation, a logical check is performed on the data contained with the block of data. If the block of data passes the logical check, then the block of data may be written to nonvolatile memory. Thereafter, when the block of data is read from nonvolatile memory a physical checksum verification procedure is performed on the block of data to determine whether the block of data was corrupted after performing the logical check on the data contained with the block of data.

    摘要翻译: 提供了一种用于维护数据完整性的方法和装置。 根据该方法,对数据块执行物理校验和计算。 在执行物理校验和计算之后,对包含在数据块中的数据执行逻辑检查。 如果数据块通过逻辑检查,则可将数据块写入非易失性存储器。 此后,当从非易失性存储器读取数据块时,对数据块执行物理校验和验证过程,以便在对包含在数据块中的数据执行逻辑检查之后,确定数据块是否已损坏。

    Reduced Disk Space Standby
    6.
    发明申请
    Reduced Disk Space Standby 有权
    减少磁盘空间待机

    公开(公告)号:US20120054158A1

    公开(公告)日:2012-03-01

    申请号:US12871795

    申请日:2010-08-30

    IPC分类号: G06F17/30 G06F12/08

    摘要: A method and system for replicating database data is provided. One or more standby database replicas can be used for servicing read-only queries, and the amount of storage required is scalable in the size of the primary database storage. One technique is described for combining physical database replication to multiple physical databases residing within a common storage system that performs de-duplication. Having multiple physical databases allows for many read-only queries to be processed, and the de-duplicating storage system provides scalability in the size of the primary database storage. Another technique uses one or more diskless standby database systems that share a read-only copy of physical standby database files. Notification messages provide consistency between each diskless system's in-memory cache and the state of the shared database files. Use of a transaction sequence number ensures that each database system only accesses versions of data blocks that are consistent with a transaction checkpoint.

    摘要翻译: 提供了一种用于复制数据库数据的方法和系统。 一个或多个备用数据库副本可用于维护只读查询,并且所需的存储量可在主数据库存储的大小上扩展。 描述了一种将物理数据库复制与驻留在执行重复数据删除的公共存储系统中的多个物理数据库进行组合的技术。 拥有多个物理数据库可以处理许多只读查询,并且重复存储系统提供主数据库存储大小的可扩展性。 另一种技术使用一个或多个共享物理备用数据库文件的只读副本的无盘备用数据库系统。 通知消息提供每个无盘系统的内存缓存与共享数据库文件的状态之间的一致性。 使用事务序列号确保每个数据库系统只能访问与事务检查点一致的数据块版本。

    Reduced disk space standby
    8.
    发明授权

    公开(公告)号:US08589361B2

    公开(公告)日:2013-11-19

    申请号:US12871795

    申请日:2010-08-30

    IPC分类号: G06F17/00

    摘要: A method and system for replicating database data is provided. One or more standby database replicas can be used for servicing read-only queries, and the amount of storage required is scalable in the size of the primary database storage. One technique is described for combining physical database replication to multiple physical databases residing within a common storage system that performs de-duplication. Having multiple physical databases allows for many read-only queries to be processed, and the de-duplicating storage system provides scalability in the size of the primary database storage. Another technique uses one or more diskless standby database systems that share a read-only copy of physical standby database files. Notification messages provide consistency between each diskless system's in-memory cache and the state of the shared database files. Use of a transaction sequence number ensures that each database system only accesses versions of data blocks that are consistent with a transaction checkpoint.

    Method and system for diagnostic preservation of the state of a computer system
    9.
    发明授权
    Method and system for diagnostic preservation of the state of a computer system 有权
    用于诊断计算机系统状态的方法和系统

    公开(公告)号:US07376864B1

    公开(公告)日:2008-05-20

    申请号:US09223660

    申请日:1998-12-30

    IPC分类号: G06F11/00

    摘要: A method and system for diagnostic preservation of the state of resources in a computer system after a failure is disclosed. An aspect of the invention is directed to the real-time diagnostic analysis of a computer system after a failure, in which the state of resources needed for the diagnostic analysis are preserved from the time of the failure. The computer system is then accessed by using other resources on the computer system, and the preserved resources are analyzed to debug the failure.

    摘要翻译: 公开了一种用于在故障后计算机系统中的资源状态的诊断保存的方法和系统。 本发明的一个方面涉及在故障之后的计算机系统的实时诊断分析,其中从故障发生时保留诊断分析所需的资源的状态。 然后通过使用计算机系统上的其他资源来访问计算机系统,并分析保留的资源来调试故障。

    Data block location verification
    10.
    发明授权
    Data block location verification 有权
    数据块位置验证

    公开(公告)号:US07231564B2

    公开(公告)日:2007-06-12

    申请号:US10824842

    申请日:2004-04-14

    IPC分类号: G11C29/00 G06F11/00

    摘要: An approach for performing data block location verification includes inserting an address value into a data block that identifies a desired location in nonvolatile memory for storing the data block. Prior to performing an operation that stores the data block to the nonvolatile memory, a determination is made whether the address value in the data block correctly identifies the location in nonvolatile memory into which the operation will store the data block. The operation is performed only if the address value in the data block correctly identifies the location in nonvolatile memory into which the operation will store the data block. After the data block is read from the nonvolatile memory, an additional determination may be made to determine whether the data block was read from the desired location in the nonvolatile memory.

    摘要翻译: 用于执行数据块位置验证的方法包括将地址值插入到标识用于存储数据块的非易失性存储器中的期望位置的数据块中。 在执行将数据块存储到非易失性存储器的操作之前,确定数据块中的地址值是否正确地识别非易失性存储器中的操作将存储数据块的位置。 仅当数据块中的地址值正确识别非易失性存储器中的操作将存储数据块的位置时才执行该操作。 在从非易失性存储器读取数据块之后,可以进一步确定是否从非易失性存储器中的期望位置读取数据块。