Abstract: A system, method, and computer readable-medium for interrupting client requests in a web environment are provided. The system includes a server, such as a web server, for receiving a request from a particular client. Rather than directly supplying the requested information, the server determines whether unrequested operations should be performed. If unrequested operations should be performed, then the server performs one or more unrequested operations before returning the originally requested information to the particular client.

Abstract: An approach for managing resources in a distributed computing system includes establishing dedicated process pools on nodes where work is to be performed. Each dedicated process pool is associated with a particular remote node and includes one or more processes. The one or more processes in each dedicated process pool perform work on behalf of processes on the associated remote node. Each dedicated process pool is managed by processes on the associated remote node using local synchronization data maintained on the associated remote node. The assignment of particular processes to perform work on behalf of processes on the associated remote node is performed by the processes on the associated remote node. In addition, the spawning of additional processes or the termination of existing processes from a dedicated process pool is managed by the processes on the associated remote node.

Abstract: An information retrieval system generates query feedback terminology for an input query based on a corpus of documents and the input query. Potential query feedback terms are identified through the corpus of documents for use as query feedback in the information retrieval system. To process a query, which includes at least one query term, co-occurrence signatures for “N” query feedback terms are generated. An N×N matrix of the co-occurrence signatures depict patterns of semantic distance and conceptual proximity among the “N” query feedback terms. The N×N matrix is processed to reduce the number of the entries in the signature to an N×M matrix while preserving the co-occurrence distance characteristics among the signatures. Query feedback terms with co-occurrence signatures, which compare with co-occurrence signatures of the query term in a predetermined manner, are selected as query feedback.

Abstract: A reliable connectionless protocol is used in a networking environment. A transport layer receives data for transfer between a source node and a destination node on a network. The transport layer divides the data into predetermined length data packets, and generates a segment header for each data packet. The transport layer generates independent segments by combining each data packet with a corresponding segment header. Consequently, each segment, including the first segment and the last segment, contains a data packet. The independent segments are transferred from the source node to the destination node via the network without establishing a connection. A transport layer on the destination node creates local state upon receipt of the first segment, and extracts the data from the data packets to re-construct the original data. The local state is released when the destination node receives the last segment in the message.

Abstract: The present invention provides a system for managing trusted certificates for authenticating communications for clients belonging to an enterprise. The system assembles a list of trusted certificates containing public keys for authenticating communications signed by associated private keys. This assembly process may include verifying the authenticity of trusted certificates in the list. The system then constructs a fingerprint for the list. The list is then communicated to a client through a first communication mechanism, and the fingerprint is communicated to the client through a second communication mechanism. Next, the client verifies that the fingerprint received through the second communication mechanism was constructed from the list of trusted certificates received through the first communication mechanism. This establishes a high degree of confidence that the list of trusted certificates is authentic.

Abstract: A mechanism for deadlock validation is provided. A potential deadlock is validated by detecting whether a state change has occurred in a member of a set of lock structures that correspond to entities and resources involved in a potential deadlock. The state change detected should have occurred after the state of the lock structures is captured during, for example, the generation of a wait-for graph. For purposes of illustration, potential deadlocks are identified by generating a wait-for graph and detecting cycles in the wait-for graph. While generating wait-for graphs, lock structures are accessed to determine whether a vertex in the wait-for graph should be generated, and the place of the vertex in the wait-for graph. After accessing a particular lock structure for this purpose, the lock structure's state is captured.

Abstract: A method and apparatus for removing changes made by a particular transaction is provided. According to one aspect, two or more sets of changes that were made by a particular transaction that can be removed in parallel are identified. A corresponding recovery process is assigned to each of the two or more sets of changes. Using the corresponding recovery process, the changes identified in each of the two or more sets of changes are undone in parallel.

Abstract: A method and apparatus for reapplying changes to a database is disclosed. A recovery log is provided for recording all changes applied to the database so that the changes may be reapplied to the database during database recovery. Whenever a change is written to a storage device, the recovery log is updated to indicate that the particular change has been written to the storage device. During recovery, the data in the recovery log is sorted by file ID, data block ID, record type and version ID.

Abstract: A method and apparatus for fast refreshing a subquery snapshot creates the snapshot based on a first table and a second table according to a snapshot definition query, which contains one or more subqueries. Information about modifications to the first and second tables is stored in first and second log, respectively. When a refresh operation is initiated, the snapshot is refreshed by reconciling differences between the snapshot, the first table and second table according to the snapshot definition query, the first log, the second log, the first table, and the second table.

Abstract: A method is provided for ensuring effective and accurate authentication and authorization in an N-tier relational database management system. An N-tier relational database management system comprises a set of clients, one or more data servers and one or more middle-tier servers through which the clients may access the data servers. A method is provided for enabling a middle-tier server to connect to a data server and perform database operations on behalf of a client while promoting the ability to ensure the middle-tier server does not exceed its authorized privileges or roles. In this method a middle-tier server first establishes a session with the data server using the middle-tier server's own identity (e.g., username) and verification (e.g., password). The middle-tier server may be granted limited roles when acting under its own identity in order to prevent it from performing unauditable or unaccountable operations on behalf of clients.

Abstract: A method and apparatus are provided for handling within a database system data items that are associated with data types whose native structure is not known to the database system. The data items are stored within the database system in their native structure, even though it is not understood by the database system. To store the data items, the database system calls a pickling routine that is provided by the user, or by the runtime subsystem of the programming environment that is native to the data item. To retrieve the routine from storage, the database system calls an unpickling routine, also provided by the user or the appropriate runtime subsystem. Because the database maintains the data items in their native format, no conversions are required as the data items are passed between the database system and external routines that manipulate the data items. Techniques are also provided for declaring attributes of the data item that can be accessed within the database system.

Abstract: A method and apparatus for performing copying garbage collection is provided. In a computer's memory, objects are stored in a permanent semispace. When a garbage collection event is detected, a garbage collection cycle is commenced. During the garbage collection cycle, the live objects in the permanent semispace are copied into a temporary semispace. After copying all the live objects into the temporary semispace, the live objects are then recopied into the permanent semispace.

Abstract: Methods and apparatus for user-directed, efficient comparisons of sets of objects. A user generally selects two sets of objects to be compared. The objects are, in general, hierarchically structured. The user may also specify criteria for selecting a desired subset of objects in the two sets of objects to be compared. In a first phase, the comparison process generates a tree containing nodes representative of each object selected to be compared; an object pair of the sets of objects being compared shares one tree node. Generally, an object pair comprises an object from each of the sets of objects being compared, and an object pair is what is compared. Container nodes are also created which represent folders of the objects being compared. A graphical representation of the tree, or an object view, is displayed as a graphical user interface display on a screen.

Abstract: A method and apparatus for paging data in a computer system is provided. A set of data associated with a program unit is divided into pages such that no item of the set of data spans more than one page. The size of one page may vary from the size of another. When the program unit is compiled, metadata is generated that indicates the division of items into pages. At load time, a page mapping is generated based on the metadata. The page mapping is used to locate a item that belongs to the set of data. Other parts of the program unit, such as byte code, can contain references to items in the constant pool. Each reference specifies the number of the page in which the corresponding item will be stored at runtime, and the offset of that item within the page.

Abstract: A database containing datafiles is partitioned into a set of tablespaces. Every disk pointer pointing to a data item in a datafile refers to a tablespace-relative file number for the datafile. Data pointed to by a tablespace-relative disk pointer is retrieved by first checking the cache, and upon a cache miss, the tablespace-relative file number is translated into an absolute file number according to a latch-free look up technique.

Abstract: An electronic calendaring and scheduling capability that minimizes storage requirements. Repetitive calendar events are stored as single entries using an expression language. The expression language provides an ability for expressing how often the event recurs. Thus, the days on which the event occurs are computed from an expression stored in a repetitive event. Further, the expression language provides the ability to identify exceptions and to define an infinite number of recurring events from the original recurrent event definition. Events are generated by obtaining a recurrency expression of a first event. The recurrency expression is converted to one or more recurring dates. A beginning date of the first event is also obtained. Using one or more recurring dates and the beginning date, one or more second events are generated in response. The present invention provides the first event and the one or more second events to the users in one or more calendars.

Abstract: A method and apparatus are provided for managing resources in a system that has multiple nodes. Each resource of a plurality of resources is assigned to a lock club of a plurality of lock clubs. A master node is assigned to each lock club of the plurality of lock clubs. All resources that belong to each given lock club are mastered at the master node assigned to the given lock club. Club-to-master mapping information that indicates the master node for each lock club of the plurality of lock clubs is maintained. Which of the multiple nodes is a master node for a particular resource is determined by inspecting the club-to-master mapping to determine the master node assigned to the lock club to which the particular resource belongs. The system may use directory nodes by storing the club-to-master mapping information for each lock club on a directory node that is selected for the lock club by applying a hash function to the name of the lock club.

Abstract: A mechanism is described for processing requests to specify operations to database objects. A request to perform an action on a set of multiple objects is received by a database system. The request includes references to each object in the set, each reference indicating a table where the respective object resides. The reference is used to locate the object, and once located, the action is performed on the object. The reference may indicate a table using a unique table id not used in any of a plurality of databases to identify a table. The action request may be to modify the object, the references may include references to objects that reside in different database systems.

Abstract: A method and apparatus for segmenting bitmaps in a bitmap index is provided. A segmented bitmap includes a plurality of bitmap segments that are used to indicate which records in a body of records that is associated with the segmented bitmap satisfy a particular criteria. Each bitmap segment contains a string of bits that correspond to a corresponding range of records in the body of records. There may be gaps between the ranges represented by the bitmap segments when, for example, the body of records does not contain records in a particular range. For the purposes of retrieval, compression, de-compression, locking and logging, the database system treats each bitmap segment as a distinct data item.

Abstract: Memory for complex objects is maintained in pools of dynamic memory on a “per-duration” basis. Each duration is assigned its own area or areas of the heap, and all the memory allocation for a specific duration comes from those assigned areas of the heap. Memory allocation for a complex object is performed with respect to a single duration and, hence, memory is allotted for the complex object from the corresponding memory pool. When a duration is terminated, the memory allocated for its corresponding heap is freed, thereby releasing memory for all the complex object using the memory from the memory pool for that duration. Management of other resources for complex objects such as opening and closing files may also be duration-based. In one aspect, the memory management of complex objects is located in an automatically generated client stub routine for a remote procedure call.