Abstract: Methods and systems for managing, storing, and serving data within a virtualized environment are described. In some embodiments, a data management system may manage the extraction and storage of virtual machine snapshots, provide near instantaneous restoration of a virtual machine or one or more files located on the virtual machine, and enable secondary workloads to directly use the data management system as a primary storage target to read or modify past versions of data. The data management system may allow a virtual machine snapshot of a virtual machine stored within the system to be directly mounted to enable substantially instantaneous virtual machine recovery of the virtual machine.

Abstract: Methods and systems for managing, storing, and serving data within a virtualized environment are described. In some embodiments, a data management system may manage the extraction and storage of virtual machine snapshots, provide near instantaneous restoration of a virtual machine or one or more files located on the virtual machine, and enable secondary workloads to directly use the data management system as a primary storage target to read or modify past versions of data. The data management system may allow a virtual machine snapshot of a virtual machine stored within the system to be directly mounted to enable substantially instantaneous virtual machine recovery of the virtual machine.

Abstract: Methods and systems for managing, storing, and serving data within a virtualized environment are described. In some embodiments, a data management system may manage the extraction and storage of virtual machine snapshots, provide near instantaneous restoration of a virtual machine or one or more files located on the virtual machine, and enable secondary workloads to directly use the data management system as a primary storage target to read or modify past versions of data. The data management system may allow a virtual machine snapshot of a virtual machine stored within the system to be directly mounted to enable substantially instantaneous virtual machine recovery of the virtual machine.

Abstract: Methods and systems for managing, storing, and serving data within a virtualized environment are described. In some embodiments, a data management system may manage the extraction and storage of virtual machine snapshots, provide near instantaneous restoration of a virtual machine or one or more files located on the virtual machine, and enable secondary workloads to directly use the data management system as a primary storage target to read or modify past versions of data. The data management system may allow a virtual machine snapshot of a virtual machine stored within the system to be directly mounted to enable substantially instantaneous virtual machine recovery of the virtual machine.

Abstract: Methods and systems for managing, storing, and serving data within a virtualized environment are described. In some embodiments, a data management system may manage the extraction and storage of virtual machine snapshots, provide near instantaneous restoration of a virtual machine or one or more files located on the virtual machine, and enable secondary workloads to directly use the data management system as a primary storage target to read or modify past versions of data. The data management system may allow a virtual machine snapshot of a virtual machine stored within the system to be directly mounted to enable substantially instantaneous virtual machine recovery of the virtual machine.

Abstract: Methods and systems for managing, storing, and serving data within a virtualized environment are described. In some embodiments, a data management system may manage the extraction and storage of virtual machine snapshots, provide near instantaneous restoration of a virtual machine or one or more files located on the virtual machine, and enable secondary workloads to directly use the data management system as a primary storage target to read or modify past versions of data. The data management system may allow a virtual machine snapshot of a virtual machine stored within the system to be directly mounted to enable substantially instantaneous virtual machine recovery of the virtual machine.

Abstract: Allocation of memory is optimized across multiple pools of memory, based on minimizing the time it takes to successfully retrieve a given data item from each of the multiple pools. First data is generated that indicates a hit rate per pool size for each of multiple memory pools. In an embodiment, the generating step includes continuously monitoring attempts to access, or retrieve a data item from, each of the memory pools. The first data is converted to second data that accounts for a cost of a miss with respect to each of the memory pools. In an embodiment, the second data accounts for the cost of a miss in terms of time. How much of the memory to allocate to each of the memory pools is determined, based on the second data. In an embodiment, the steps of converting and determining are automatically performed, on a periodic basis.

Abstract: A method and apparatus for maintaining an item-to-node mapping among nodes in a distributed cluster is provided. Each node maintains locally-stored system-state information indicating that node's understanding of which master nodes are alive and dead. Instead of employing a global item-to-node mapping, each node acts upon a locally determined mapping based on its locally-stored system-state information. For any two nodes with the same locally-stored system-state information, the locally determined mapping is the same. A node updates its locally-stored system-state information upon detecting a node failure or receiving a message from another node indicating different locally-stored system-state information. The new locally-stored system-state information is transmitted on a need-to-know basis, and consequently nodes with different item-to-node mappings may operate concurrently.

Abstract: A number, of the blocks of data to be prefetched into a buffer cache, is determined dynamically at run time (e.g. during execution of a query), based at least in part on the load placed on the buffer cache. An application program (such as a database) is responsive to the number (also called “prefetch size”), to determine the amount of prefetching. A sequence of instructions (also called “prefetch size daemon”) computes the prefetch size based on, for example, the number of prefetched blocks aged out before use. The prefetch size daemon dynamically revises the prefetch size based on usage of the buffer cache, thereby to form a feedback loop. Depending on the embodiment, at times of excessive use of the buffer cache, prefetching may even be turned off.

Abstract: Provided herein is a mechanism that allows a given database system to access data blocks from another database system, where data blocks from the given database system and data blocks from the other database system have different sizes. According to an aspect of the present invention, a tablespace in the other database system contained the data blocks. The tablespace is detached from the other database system and integrated into the given database, which is capable of processing data stored in data blocks of different sizes.

Abstract: 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.

Abstract: Provided herein is a mechanism that allows a given database system to access data blocks from another database system, where data blocks from the given database system and data blocks from the other database system have different sizes. According to an aspect of the present invention, a tablespace in the other database system contained the data blocks. The tablespace is detached from the other database system and integrated into the given database, which is capable of processing data stored in data blocks of a different sizes.

Abstract: A method and mechanism is disclosed for implementing transaction logging in a database system. In-memory undo records are maintained to log undo information for the database system. Redo records are batch processed, with multiple redo records for a transaction stored on disk at commit time.

Abstract: A system and methods for simulating the performance (e.g., miss rate) of one or more caches. A cache simulator comprises a segmented list of buffers, with each buffer configured to store a data identifier and an identifier of the buffer's segment. Data references, which may be copied from an operational cache, are applied to the list to conduct the simulation. Initial estimates of each cache's miss rate include the number of references that missed all segments of the list plus the hits in all segments not part of the cache. A correction factor is generated from the ratio of actual misses incurred by the operational cache to the estimated misses for a simulated cache of the same size as the operational cache. Final predictions are generated by multiplying the initial estimates by the correction factor. The size of the operational cache may be dynamically adjusted based on the final predictions.

Abstract: Allocation of memory is optimized across multiple pools of memory, based on minimizing the time it takes to successfully retrieve a given data item from each of the multiple pools. First data is generated that indicates a hit rate per pool size for each of multiple memory pools. In an embodiment, the generating step includes continuously monitoring attempts to access, or retrieve a data item from, each of the memory pools. The first data is converted to second data that accounts for a cost of a miss with respect to each of the memory pools. In an embodiment, the second data accounts for the cost of a miss in terms of time. How much of the memory to allocate to each of the memory pools is determined, based on the second data. In an embodiment, the steps of converting and determining are automatically performed, on a periodic basis.

Abstract: 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.

Abstract: A method and mechanism is disclosed for implementing transaction logging in a database system. In-memory undo records are maintained to log undo information for the database system. Redo records are batch processed, with multiple redo records for a transaction stored on disk at commit time.

Abstract: Provided herein is a mechanism that allows a given database system to access data blocks from another database system, where data blocks from the given database system and data blocks from the other database system have different sizes. According to an aspect of the present invention, a tablespace in the other database system contained the data blocks. The tablespace is detached from the other database system and integrated into the given database, which is capable of processing data stored in data blocks of a different sizes.