摘要:
Embodiments of the present invention provide fine grain concurrency control for transactions in the presence of database updates. During operations, each transaction is assigned a snapshot version number or SVN. A SVN refers to a historical snapshot of the database that can be created periodically or on demand. Transactions are thus tied to a particular SVN, such as, when the transaction was created. Queries belonging to the transactions can access data that is consistent as of a point in time, for example, corresponding to the latest SVN when the transaction was created. At various times, data from the database stored in a memory can be updated using the snapshot data corresponding to a SVN. When a transaction is committed, a snapshot of the database with a new SVN is created based on the data modified by the transaction and the snapshot is synchronized to the memory. When a transaction query requires data from a version of the database corresponding to a SVN, the data in the memory may be synchronized with the snapshot data corresponding to that SVN.
摘要:
Embodiments of the present invention provide fine grain concurrency control for transactions in the presence of database updates. During operations, each transaction is assigned a snapshot version number or SVN. A SVN refers to a historical snapshot of the database that can be created periodically or on demand. Transactions are thus tied to a particular SVN, such as, when the transaction was created. Queries belonging to the transactions can access data that is consistent as of a point in time, for example, corresponding to the latest SVN when the transaction was created. At various times, data from the database stored in a memory can be updated using the snapshot data corresponding to a SVN. When a transaction is committed, a snapshot of the database with a new SVN is created based on the data modified by the transaction and the snapshot is synchronized to the memory. When a transaction query requires data from a version of the database corresponding to a SVN, the data in the memory may be synchronized with the snapshot data corresponding to that SVN.
摘要:
Embodiments of the present invention provide a run-time scheduler that schedules tasks for database queries on one or more execution resources in a dataflow fashion. In some embodiments, the run-time scheduler may comprise a task manager, a memory manager, and hardware resource manager. When a query is received by a host database management system, a query plan is created for that query. The query plan splits a query into various fragments. These fragments are further compiled into a directed acyclic graph of tasks. Unlike conventional scheduling, the dependency arc in the directed acyclic graph is based on page resources. Tasks may comprise machine code that may be executed by hardware to perform portions of the query. These tasks may also be performed in software or relate to I/O.
摘要:
Embodiments of the present invention provide a run-time scheduler that schedules tasks for database queries on one or more execution resources in a dataflow fashion. In some embodiments, the run-time scheduler may comprise a task manager, a memory manager, and hardware resource manager. When a query is received by a host database management system, a query plan is created for that query. The query plan splits a query into various fragments. These fragments are further compiled into a directed acyclic graph of tasks. Unlike conventional scheduling, the dependency arc in the directed acyclic graph is based on page resources. Tasks may comprise machine code that may be executed by hardware to perform portions of the query. These tasks may also be performed in software or relate to I/O.
摘要:
A file that has a holding portion configured for holding at least one stack of paper at a holding location. A first panel covers the holding location, and a second panel includes a traction surface and is rotatably associated with the first panel for movement between closed and open positions. In the closed position, the second panel is disposed against another portion of the file and in the open position, the second panel extends at an angle from the holding location for resting on a desktop. A traction surface has sufficiently high traction for supporting the holding portion and its held stack hanging therefrom while preventing the second panel from sliding off the desktop.
摘要:
A file that includes a first panel disposed adjacent a holding location, a holding member associated with the first panel and being configured and dimensioned for holding and retaining a stack of paper in the holding location, and a second panel that includes a high-traction surface that has a sufficiently high frictional coefficient to provide elevated traction and gripping against a desktop to resist or prevent sliding thereagainst. The second panel is rotatably associated with the first panel for movement between a closed position and an open position.
摘要:
An electrical connector including a connector section and a connector performance indicating section. The connector section includes a first connection section adapted to connect to a first electrical conductor and a second connection section adapted to connect to a second electrical conductor. The connector section is adapted to electrical connect the first electrical conductor to the second electrical conductor. The connector performance indicating section is connected to a portion of the connector section. The connector performance indicating section includes a temperature sensitive indicator adapted to signal occurrence of a temperature of the portion of the connector section above a predetermined temperature. The temperature sensitive indicator comprises a Radio Frequency Identification (RFID) tag.
摘要:
A system (e.g., a power supply) is presented which allows a user to electrically couple a common ground electrical potential of a circuit (e.g., a power supply circuit return) to, or electrically isolate the common ground electrical potential from, an earth grounded chassis, without having to open the chassis. The system may include a metal bolt and nut, wherein the nut is coupled to an electrically conductive bracket. The bracket is mounted upon a printed circuit board and electrically coupled to the common ground electrical potential. When an insulating bushing is installed in a hole in the chassis adjacent to the bracket, and a threaded shaft of the bolt extends through aligned holes in the insulating bushing, an insulating member positioned between the bracket and the chassis, and the bracket, and the threaded shaft engages the nut, the bolt holds the insulating bushing in place, and the bracket is electrically isolated from the chassis. When the insulating bushing is replaced with a conductive washer, the bolt and the conductive washer form a conductive electrical path between the bracket and the chassis. Components of the described system may be employed in systems having multiple cabinets (or complex cabinet systems) to achieve a single point of grounding. System components may also be employed to selectively isolate or couple a power supply return to a chassis ground in devices other than power supplies.
摘要:
A pipe pick-up and lay down apparatus for lifting and lowering materials between a support frame and a rig floor of a workover rig, includes a support frame, a lifting arm, a controller and a lifting assembly for lifting and lowering the lifting arm. The lifting arm may be disposed in a trench in the support frame table and is substantially the same length and width as the trench and when in a lowered position. The lifting assembly may optionally include a power supply, a plurality of cables, and is operated by the controller to raise and lower the lifting arm.
摘要:
A hand-held, battery-powered, hydraulically-actuated tool including a frame forming a tool longitudinal axis; a battery offset from the tool longitudinal axis; and located along the tool longitudinal axis a motor connected to the battery; a hydraulic fluid pump connected to the motor, such as by a transmission; a ram movably connected to the frame and adapted to be moved relative to the frame by hydraulic fluid pumped by the hydraulic fluid pump; and a working head adapted to be actuated by the ram. The tool includes a main section situated in an in-line configuration along the tool longitudinal axis. A center longitudinal axis of the battery is offset from the tool longitudinal axis.