Oracle International Corporation

Michael J Cusson

Richard L Frank

Daniel E O'Shaughnessy

Joydip Kundu

Gopalan Arun

Juan R Loaiza

Ramu V Sunkara

Dan O'Shaughnessy

Marcos G Almeida

Anil J D'Silva

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.

System for extending an addressable range of memory

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.

Method and mechanism for relational access of recovery logs in a database system

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. The cache receives a query context of global data set identifiers, determines whether the data sets of the query context are cached, and if they are, provides the local data set identifiers for the query context to the access layer, which then uses the local data set identifiers to query the cache.

Web servers with queryable dynamic caches

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 nodesto 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.

Providing figure of merit vote from application executing on a partitioned cluster

Using a cluster-wide shared repository to provide the latest consistent definition of the cluster (avoiding the partition-in time problem)

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.

Quorumless cluster using disk-based messaging

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 &ldquo;view,&rdquo; 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.

Closed-loop node membership monitor for network clusters

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.

System for efficiently maintaining translation lockaside buffer consistency in a multi-threaded, multi-processor virtual memory system

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. There are three statuses: miss, indicating that the item is not in the cache, hit, indicating that it is, and unknown, indicating that it is not known whether the item is in the cache. When an item is referenced, the query used to access it is presented to the table. If the entry for the query has the status miss, the data access layer obtains the item from the data source instead of attempting to obtain it from the cache. If the entry has the status unknown, the data access layer attempts to obtain it from the cache and the miss table entry for the item is updated in accordance with the result. When a copy of an item is added to the cache, miss table entries with the status miss are set to indicate unknown.

Growing community of inventors

Chelmsford, MA, United States of America

Michael J Cusson