Abstract: An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Abstract: A logical clock is implemented in networked nodes. Messages between nodes can include either a scalar timestamp or a vector timestamp. The scalar timestamp leads to an overhead reduction, and nodes can select whether to send a scalar or vector timestamp depending on requirements. Message recipients update their logical clock vector differently depending on whether the scalar or vector timestamp is received. Applications to multi-master databases are also provided. The clock conforms to Lamport clock requirements when the scalar timestamp is sent, and conforms to both Lamport and vector clock requirements when the vector timestamp is sent.

Abstract: A method of reducing write amplification in an append-only memory store of data records, by which the store is subdivided into streams, each of which for storing records having an update frequency within a variable range of update frequencies. By defining an update frequency that does not rely on time, statistical methods can be used to select the streams in which data records can be written. The range of update frequencies of each stream can be fixed or variable and based on the stored records. The memory allocated to each stream can be determined based on numerically solving an optimization problem that determines the write amplification resulting from different memory allocations in the streams.

Abstract: An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Abstract: Methods and apparatuses in a cloud-based database management system are described. Data in a database are stored in a plurality of pages in a page store of the database. A plurality of redo log records are received to be applied to the database. The redo log records within a predefined boundary are parsed to determine, for each given redo log record, a corresponding page to which the given log record is to be applied. The redo log records are reordered by corresponding page. The reordered redo log records are stored to be applied to the page store of the database.

Abstract: A method of reducing write amplification in an append-only memory store of data records, by which the store is subdivided into streams, each of which for storing records having an update frequency within a variable range of update frequencies. By defining an update frequency that does not rely on time, statistical methods can be used to select the streams in which data records can be written. The range of update frequencies of each stream can be fixed or variable and based on the stored records. The memory allocated to each stream can be determined based on numerically solving an optimization problem that determines the write amplification resulting from different memory allocations in the streams.

Abstract: An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Abstract: A method includes receiving an indication of a change to a page of a database and adding a new log record corresponding to the page to a common log comprising log records, the new log record describing the change made to the page and assigned a distinct version number. The method further includes synchronously writing the new log record to each log store replica in a set of log store replicas, and asynchronously writing the new log record to all page store replicas for the page to update the page that is stored on each of the page store replicas, where each store replica for the page serves reads for the page. In response to receiving, from a predetermined number of the page store replicas, an acknowledgement of the writing of the log record, discarding the new log record from the common log.

Abstract: Methods and apparatuses in a cloud-based database management system are described. Data in a database are stored in a plurality of pages in a page store of the database. A plurality of redo log records are received to be applied to the database. The redo log records within a predefined boundary are parsed to determine, for each given redo log record, a corresponding page to which the given log record is to be applied. The redo log records are reordered by corresponding page. The reordered redo log records are stored to be applied to the page store of the database.

Abstract: An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Abstract: Systems and methods for switching a data access synchronization strategy for a data structure are provided. Workload characteristics of one or more threads of execution access the data structure are monitored. A target data access synchronization strategy is determined. If the current strategy is different than the target strategy, the current strategy is switched to the target data access synchronization strategy for the data structure.

Abstract: A method includes receiving an indication of a change to a page of a database and adding a new log record corresponding to the page to a common log comprising log records, the new log record describing the change made to the page and assigned a distinct version number. The method further includes synchronously writing the new log record to each log store replica in a set of log store replicas, and asynchronously writing the new log record to all page store replicas for the page to update the page that is stored on each of the page store replicas, where each store replica for the page serves reads for the page. In response to receiving, from a predetermined number of the page store replicas, an acknowledgement of the writing of the log record, discarding the new log record from the common log.

Abstract: An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Abstract: Systems and methods for switching a data access synchronization strategy for a data structure are provided. Workload characteristics of one or more threads of execution access the data structure are monitored. A target data access synchronization strategy is determined. If the current strategy is different than the target strategy, the current strategy is switched to the target data access synchronization strategy for the data structure.

Abstract: An apparatus is disclosed. The apparatus may be implemented in a database node or a storage node and includes one or more processors and memory storing instructions for causing the processor to perform a number of operations. Responsive to a page write request, the apparatus determines an identifier corresponding to the requested page, sends component blocks corresponding to the page to a storage node for appending to an append-only storage log of the storage node, receives the physical location of the stored component blocks, and associates the physical storage location of the stored component blocks with the logical identifier corresponding to the page.

Abstract: A system and method for dividing complex tasks into sub-tasks for the purpose of improving performance in completing the task. Sub-tasks are arranged hierarchically and if a sub-task is unable to obtain a thread for execution it is executed in the thread of the parent task. Should a thread become free it is returned to a thread pool for use by any task. Should a parent task be waiting on the completion of one or more sub-tasks, the thread it uses is returned to the thread pool for use by any other task as needed.