摘要:
Aspects of the subject matter described herein relate to a buffer pool for a database system. In aspects, secondary memory such as solid state storage is used to extend the buffer pool of a database system. Thresholds such as hot, warm, and cold for classifying pages based on access history of the pages may be determined via a sampling algorithm. When a database system needs to free space in a buffer pool in main memory, a page may be evicted to the buffer pool in secondary memory or other storage based on how the page is classified and conditions of the secondary memory or other storage.
摘要:
A buffer manager that manages blocks of memory amongst multiple levels of buffer pools. For instance, there may be a first level buffer pool for blocks in first level memory, and a second level buffer pool for blocks in second level memory. The first level buffer pool evicts blocks to the second level buffer pool if the blocks are not used above a first threshold level. The second level buffer pool evicts blocks to a yet lower level if they have not used above a second threshold level. The first level memory may be dynamic random access memory, whereas the second level memory may be storage class memory, such as a solid state disk. By using such a storage class memory, the working block set of the buffer manager may be increased without resorting to lower efficiency random block access from yet lower level memory such as disk.
摘要:
A buffer manager that manages blocks of memory amongst multiple levels of buffer pools. For instance, there may be a first level buffer pool for blocks in first level memory, and a second level buffer pool for blocks in second level memory. The first level buffer pool evicts blocks to the second level buffer pool if the blocks are not used above a first threshold level. The second level buffer pool evicts blocks to a yet lower level if they have not used above a second threshold level. The first level memory may be dynamic random access memory, whereas the second level memory may be storage class memory, such as a solid state disk. By using such a storage class memory, the working block set of the buffer manager may be increased without resorting to lower efficiency random block access from yet lower level memory such as disk.
摘要:
A system and method for providing scaleable recovery for a multiplexed transactional log. Unlike a dedicated log that includes log data of only one client, a multiplexed transactional log may include log data from multiple clients. In a multiplexed transactional log, log data from different clients may be multiplexed into the multiplexed transactional log in any order. The multiplexed log is maintained for multiple clients using a scaleable logging process. After a system failure, the multiplexed log is recovered using a scaleable recovery process. The scaleable recovery process includes an end-of-log locating process for locating the end of the multiplexed log and each of the virtual logs with the multiplexed log. The end-of-log locating process is also scaleable.
摘要:
A common logging system (a “virtual logging system”) that presents to one or more log clients the appearance that each log client is interacting with a dedicated logging system. In reality, the virtual logging system is multiplexing virtual log streams, including log records, for each log client into a single transactional log. In particular, the invention is directed at a system and method for decoupling space reservation between a plurality of distributed components and a core component in the virtual logging system.
摘要:
A system and method for providing scaleable recovery for a multiplexed transactional log. Unlike a dedicated log that includes log data of only one client, a multiplexed transactional log may include log data from multiple clients. In a multiplexed transactional log, log data from different clients may be multiplexed into the multiplexed transactional log in any order. The multiplexed log is maintained for multiple clients using a scaleable logging process. After a system failure, the multiplexed log is recovered using a scaleable recovery process. The scaleable recovery process includes an end-of-log locating process for locating the end of the multiplexed log and each of the virtual logs with the multiplexed log. The end-of-log locating process is also scaleable.
摘要:
A common logging system (a “virtual logging system”) that presents to one or more log clients the appearance that each log client is interacting with a dedicated logging system. In reality, the virtual logging system is multiplexing virtual log streams, including log records, for each log client into a single transactional log. In particular, the invention is directed at a scheme for mapping virtual identifiers that a client uses in connection with the client's own records to physical identifiers that represent the physical location of the client's records in the single transactional log
摘要:
A common transactional logging system (a “virtual logging system”) that presents to one or more log clients the appearance that each log client is interacting with a dedicated logging system. In reality, the virtual logging system is multiplexing multiple virtual log streams, including log records, for each log client into a single transactional log.
摘要:
A method and system for establishing more direct access to a storage device from unprivileged code are described. Using a storage infrastructure mechanism to discover and enumerate storage architecture component(s), a user mode application requests a portion of the storage device to store application-related data. That portion is mapped to an address space representing the application-related data. The storage infrastructure mechanism determines whether the user mode application is authorized to access the storage device and if satisfied, the storage infrastructure mechanism configures at least one path for the user mode application to perform block-level input/output between the storage device and an unprivileged storage architecture component. A completion notification mechanism may be selected or established for returning information related to input/output requests.
摘要:
The subject disclosure is directed towards establishing more direct access to a storage device from unprivileged code. Using a storage infrastructure mechanism to discover and enumerate storage architecture component(s), a user mode application requests at least one portion of the storage device to store application-related data. The storage infrastructure mechanism determines whether the application is authorized to access the storage device and if satisfied, the storage infrastructure mechanism configures at least one path for performing block-level input/output between the storage device and an unprivileged storage architecture component.