Abstract: A method and system provides a requested memory to a requesting process. The memory is requested by a consumer process residing in application space. The consumer process requests the requested memory from a Very Large Memory (VLM) driver in the operating system. The size of the requested memory may be larger than the maximum size per process supported by the operating system. The VLM driver creates one or more donor processes residing in application space dependent on the size of the requested memory. Each donor process requests an allocation of a portion of memory less than the maximum size per process supported by the operating system. Having received the requested memory, the donor process transfers ownership of the portion of memory to the VLM driver. The VLM driver provides the requested memory provided by the donor processes to the consumer process.

Abstract: The present invention is directed to a method and mechanism for accessing recovery log information in a database system. The data stored in the recovery log is presented as a relational database “view,” which can be queried and accessed using relational database statements even though the underlying recovery log data may be stored in a non-relational format. According to an aspect of the invention, the recovery log data is thus encapsulated by the view presented to users of that data.

Abstract: A middle-tier Web server with a queryable cache that contains items from one or more data sources. Items are included in the cache on the basis of the probability of future hits on the items. When the data source determines that an item that has been included in the cache has changed, it sends an update message to the server, which updates the item if it is still included in the cache. As disclosed, the data source is a database system and triggers in the database system are used to generate update messages. The data access layer determines whether a data item required by an application program is in the cache. If it is, the data access layer obtains the data item from the cache; otherwise, it obtains it from the data source. The Web application programs use global data set identifiers to identify data sets, while the cached data sets are identified by local data set identifiers.

Abstract: A method and system provides a requested memory to a requesting process. The memory is requested by a consumer process residing in application space. The consumer process requests the requested memory from a Very Large Memory (VLM) driver in the operating system. The size of the requested memory may be larger than the maximum size per process supported by the operating system. The VLM driver creates one or more donor processes residing in application space dependent on the size of the requested memory. Each donor process requests an allocation of a portion of memory less than the maximum size per process supported by the operating system. Having received the requested memory, the donor process transfers ownership of the portion of memory to the VLM driver. The VLM driver provides the requested memory provided by the donor processes to the consumer process.

Abstract: A quorumless network cluster provides a highly available system by addressing the partition-in-space and partition-in-time problems in network clusters. In a particular solution, a cluster manager (CM) can use disk based messaging to manage the operation of the cluster. Each node within the cluster must have access to a shared disk to operate within the cluster. A particular methodology can operate the cluster in a closed loop between nodes 1 to N. If a node fails to receive a heartbeat message from its predecessor in the loop, it initiates a cluster reconfiguration by sending a reconfiguration message to each other node in the cluster. The quorumless cluster can also include a common storage for a cluster definition. Each node may provide a proposed change to the cluster definition, however only a single coordinator node may update the cluster definition and apply the suggested changes.

Abstract: A quorumless network cluster provides a highly available system by addressing the partition-in-space and partition-in-time problems in network clusters. In a particular solution, a cluster manager (CM) can use disk based messaging to manage the operation of the cluster. Each node within the cluster must have access to a shared disk to operate within the cluster. A particular methodology can operate the cluster in a closed loop between nodes 1 to N. If a node fails to receive a heartbeat message from its predecessor in the loop, it initiates a cluster reconfiguration by sending a reconfiguration message to each other node in the cluster. The quorumless cluster can also include a common storage for a cluster definition. Each node may provide a proposed change to the cluster definition, however only a single coordinator node may update the cluster definition and apply the suggested changes.

Abstract: A quorumless network cluster provides a highly available system by addressing the partition-in-space and partition-in-time problems in network clusters. In a particular solution, a cluster manager (CM) can use disk based messaging to manage the operation of the cluster. Each node within the cluster must have access to a shared disk to operate within the cluster. A particular methodology can operate the cluster in a closed loop between nodes 1 to N. If a node fails to receive a heartbeat message from its predecessor in the loop, it initiates a cluster reconfiguration by sending a reconfiguration message to each other node in the cluster.

Abstract: The present invention is directed to a method and mechanism for accessing recovery log information in a database system. The data stored in the recovery log is presented as a relational database “view,” which can be queried and accessed using relational database statements even though the underlying recovery log data may be stored in a non-relational format. According to an aspect of the invention, the recovery log data is thus encapsulated by the view presented to users of that data.

Abstract: The present invention is directed to a method and mechanism for accessing recovery log information in a database system. The data stored in the recovery log is presented as a relational database “view,” which can be queried and accessed using relational database statements even though the underlying recovery log data may be stored in a non-relational format. According to an aspect of the invention, the recovery log data is thus encapsulated by the view presented to users of that data.

Abstract: A quorumless network cluster provides a highly available system by addressing the partition-in-space and partition-in-time problems in network clusters. In a particular solution, a cluster manager (CM) can use disk based messaging to manage the operation of the cluster. Each node within the cluster must have access to a shared disk to operate within the cluster. A particular methodology can operate the cluster in a closed loop between nodes 1 to N. If a node fails to receive a heartbeat message from its predecessor in the loop, it initiates a cluster reconfiguration by sending a reconfiguration message to each other node in the cluster. The quorumless cluster can also include a common storage for a cluster definition. Each node may provide a proposed change to the cluster definition, however only a single coordinator node may update the cluster definition and apply the suggested changes.

Abstract: A method for maintaining virtual memory consistency in a multi-processor environment comprises allocating a subset of virtual memory to a process, and mapping the subset of virtual memory to a first subset of physical memory. A translator lookaside buffer (TLB) is maintained in each processor, each TLB comprising a plurality of TLB entries. Each TLB entry represents a mapping between a virtual address in the subset of virtual memory and a physical address in the first subset of physical memory. When the subset of virtual memory is to be unmapped, a reference to the first subset of physical memory is placed into a free list, and marked as dirty. When the number of dirty references exceeds a predetermined threshold, the corresponding entries in each processor's TLB are invalidated. Alternatively, all TLB entries can be invalidated. The free list comprises a plurality of free list entries, where each entry comprises a reference to virtual memory which is either unmapped or whose mapping is dirty.

Abstract: A middle-tier Web server with a queryable cache that contains items from one or more data sources. Items are included in the cache on the basis of the probability of future hits on the items. When the data source determines that an item that has been included in the cache has changed, it sends an update message to the server, which updates the item if it is still included in the cache. In a preferred embodiment, the data source is a database system and triggers in the database system are used to generate update messages. In a preferred embodiment, the data access layer determines whether a data item required by an application program is in the cache. If it is, the data access layer obtains the item from the cache; otherwise, it obtains the item from the data source. The queryable cache includes a miss table that accelerates the determination of whether a data item is in the cache. The miss table is made up of miss table entries that relate the status of a data item to the query used to access the data item.