摘要:
In an embodiment, estimated costs are used to pick the best refresh technique (e.g., method) for a given MV. In another embodiment, estimated costs are used to schedule the refresh of a set MVs in an order such that overall time to refresh is reduced, or in an order that uses the smallest overall time, for refreshing when compared to other alternative refresh schedules. In another embodiment, the estimated cost of refreshing each of a set of MVs is used to select the set of CPU resources to allocate to refreshing each MV. Based on the estimated costs, the allocation of CPU resources is chosen to be more optimal (e.g., use less CPU time) than other available sets of CPU resources. In an embodiment, when refreshing an MV, delayed index maintenance is chosen if a significant portion of the base table and/or the partitions of the table has changed.
摘要:
Activity Duration Locking (ADL) provides an efficient simple solution to manage a potentially large number of concurrently active lock groups. The ADL scheme allows a transaction fine control over creation of lock groups and classification of locks into lock groups enabling faster releasing of locks in groups. The life time that the lock group is active defines a new lock duration. This allows a large number of lock durations to be defined with the creation of each new lock group and any number of lock durations can be active for a given transaction. A very general concept of lock duration is supported without using any a priori semantics to individual lock durations and the duration of a lock group may be determined by the transaction as desired.
摘要:
In a multidimensional database, an aggregation operation is performed in an optimal manner by storing the values included in the/aggregation operation on the same disk page. A sparsity manager determines aggregate values that are computed from other data values during the aggregation operation. Each aggregate value is associated with one or more data values that are used during the aggregation operation to compute the aggregate value. The sparsity manager stores the associated data values in proximity to each other, such as on the same disk page, so that multiple disk page fetches may not be required for the same set of data values during the aggregation operation. The data values used in the aggregation operation can therefore be fetched once from a disk page, and thereafter are found in memory, such as on a cache page corresponding to the disk page. In this manner, multiple fetches for the same disk page during the aggregation operation are avoided.
摘要:
An executable computer program is dynamically constructed by tightly coupling a plurality of dynamically loadable modules. Each modules includes a fully encapsulated function which is typically called from another module. A registration system is employed to associate a pointer with each defined function. In the modules, at run time, each function call is resolved using the associated pointer from the registration system. In particular, each function call is dereferenced by the associated pointer. Consequently, the resulting executable computer program is both flexible and efficient.
摘要:
Techniques are provided for managing caches in a system with multiple caches that may contain different copies of the same data item. Specifically, techniques are provided for coordinating the write-to-disk operations performed on such data items to ensure that older versions of the data item are not written over newer versions, and to reduce the amount of processing required to recover after a failure. Various approaches are provided in which a master is used to coordinate with the multiple caches to cause a data item to be written to persistent storage. Techniques are also provided for managing checkpoints associated with the caches, where the checkpoints are used to determine the position at which to begin processing recovery logs in the event of a failure.
摘要:
A system and method for facilitating real-time collaboration. A real-time collaboration server comprises a number of communication modules for handling communications with individual clients. An organizer manages the collaboration and includes a control unit for each mode (e.g., desktop sharing, whiteboard, chat). Incoming communications are routed to the appropriate control unit by a filter. The control unit queues sets of collaboration data for distribution to clients through separate communication modules. When a client acknowledges one set of data sent to it, the next set can be sent. A roster control unit maintains a roster of clients, including their permissions and properties. A client's permissions may be verified when a communication is received from or is to be sent to the client.
摘要:
Techniques are provided for communicating data to a mobile device. A system receives a request for data from a mobile device. The system identifies filter criteria associated with the mobile device. The filter criteria is applied to a set of data to identify particular data elements that satisfy the filter criteria. The identified data elements are then transmitted to the mobile device.
摘要:
Methods are provided for communicating with and regulating access to a storage system contained within a file system. Storage access keys are used to communicate to the file system changes in location of data stored in the storage system. Fence keys are used to regulate access to the storage system.
摘要:
Editing query conditions, calculations, formulas and equations, or any other parts of a form includes providing a hyperlink for an element in the form to indicate to a user that a control is available for the element. Upon a selection of the hyperlink by the user, the control is presented for user interaction. Upon completion of user interaction with the control, the element is replaced with a new element responsive to user action. The control can be a list of choices, such as a pull-down menu, a dialog box, or a text entry field. The hyperlink can be color coded and underlined.
摘要:
A mechanism is described for determining whether a password may be used in a system that determines access privileges based on passwords. A computer system, such as a database system, receives user supplied routines that are each associated with a group of users. A proposed password (e.g. string) is received that is associated with a particular user that belongs to particular group. The user supplied routine associated with the group is used to determine whether the proposed password may be used as a password.