Abstract: For an information retrieval system coupled to a buffer pool maintaining a plurality of pages of recently accessed information for subsequent re-access, a technique for starting the buffer pool is provided. The technique facilitates a quicker start to the buffer pool by deferring allocation of page storing portions, for example, until they are needed. The technique makes the buffer pool available for storing pages while deferring allocation of a page storing portion of the buffer pool and allocates the page storing portion of the buffer pool in response to a demand to store pages to the buffer pool. The technique may be used to re-start a buffer pool with pages stored to a memory coupled to the information retrieval system where the pages where stored upon a buffer pool shutdown. Further, buffer pool readers or prefetchers may be configured to read pages for storing to the buffer pool and allocate the page storing portions of the buffer pool in response to instructions to read particular pages.

Abstract: A system and method for managing shared resources is disclosed. The system includes a primary coherency processing unit which processes lock requests from a plurality of data processing hosts, the primary coherency processing unit also storing a first current lock state information for the plurality of data processing hosts, the first current lock state information including a plurality of locks held by the plurality of data processing hosts. The system further includes a standby coherency processing unit storing fewer locks than the primary coherency processing unit, the locks stored by the standby coherency processing unit being a subset of locks included in the first current lock state information, the standby coherency unit configured to perform a plurality of activities of the primary coherency processing unit using the subset of locks in response to a failure of the primary coherency processing unit.

Abstract: Embodiments of the invention provide a method for regaining memory consistency after a trap via transactional memory. Transactional memory and a transactional memory log are used to undo changes made to memory from a transaction start point up to the point of a trap event. After the trap event is processed, and the changes are rolled back, the program can resume execution at the beginning of the transaction.

Abstract: A computer system dynamically scales back latch requests for system resources. Tasks seeking access to system resources each dynamically determine the probability that the task will gain access to the latch relating to a given system resource. Where the task estimates that its probability is below a defined threshold, the task will suspend itself for a defined sleep time. The task dynamically adjusts the length of the sleep time based on the number of times the task enters the suspended state and on the relative changes in the estimated probability that the task will gain access to the resource.

Abstract: A method for implementing distributed database management system operations on a computer cluster. The method includes defining ownership relationships between a plurality of computers in the computer cluster and a plurality of data nodes in the computer cluster, wherein a distributed database management system operation can be directly carried out by a first computer only on those data nodes owned by the first computer. The method further includes monitoring database usage characteristics. The method further includes carrying out a re-architecture step in response to the database usage characteristics by redefining ownership relationships to improve the efficiency of the distributed database management system operations.

Abstract: A system and method for managing shared resources is disclosed. The system includes a primary coherency processing unit which processes lock requests from a plurality of data processing hosts, the primary coherency processing unit also storing a first current lock state information for the plurality of data processing hosts, the first current lock state information including a plurality of locks held by the plurality of data processing hosts. The system further includes a standby coherency processing unit storing fewer locks than the primary coherency processing unit, the locks stored by the standby coherency processing unit being a subset of locks included in the first current lock state information, the standby coherency unit configured to perform a plurality of activities of the primary coherency processing unit using the subset of locks in response to a failure of the primary coherency processing unit.

Abstract: A coherency manager provides coherent access to shared data by receiving a copy of updated database data from a host computer through RDMA, the copy including updates to a given database data; storing the copy of the updated database data as a valid copy of the given database data in local memory; invalidating local copies of the given database data on other host computers through RDMA; receiving acknowledgements from the other host computers through RDMA that the local copies of the given database data have been invalidated; and sending an acknowledgement of receipt of the copy of the updated database data to the host computer through RDMA. When the coherency manager receives a request for the valid copy of the given database data from a host computer through RDMA, it retrieves the valid copy of the given database data from the local memory and returns the valid copy through RDMA.

Abstract: An ordering of operations in log records includes: performing update operations on a shared database object by a node; writing log records for the update operations into a local buffer by the node, the log records each including a local virtual timestamp; determining that a log flush to write the log records in the local buffer to a persistent storage is to be performed; in response, sending a request from the node to a log flush sequence server for a log flush sequence number; receiving the log flush sequence number by the node; inserting the log flush sequence number into the log records in the local buffer; and performing the log flush to write the log records in the local buffer to the persistent storage, where the log records written to the persistent storage comprises the local virtual timestamps and the log flush sequence number.

Abstract: Lock communications in a shared disk database system is reduced by several approaches: sending a single message to a lock manager for locks required for an operation and locks that will be required in the future, the operations may include row update, row delete, large scan, and row insert; performing an operation in two executions, where in a first execution locks required for the operation is determined without performing the operation, and in a second execution a single message is sent to a lock manager for the required locks and the operation is performed; in free space searching, sending a single message to a lock manager for row and page locks before a row insert is actually performed; and granting locks in an unfair manner.

Abstract: distributed database management system implemented on a cluster of computers. The cluster including disks organized as data nodes. The data nodes being locally connected to one or more computers in the cluster. The distributed database management system includes a distributed database manager layer having a lock manager, a resource manager, and an architecture manager. The lock manager serializes access to the data nodes in the cluster. The resource manager maintains a data representation of the resources of each computer in the cluster and makes the data available to other computers in the cluster to facilitate access to the resources by the other computers. The architecture manager defines logical ownership relationships between data nodes and computers in the cluster to permit the architecture of the database to be dynamically reconfigured to provide improved performance.

Abstract: A method for implementing a set of database management components in a distributed database management system, the distributed database management system being implemented on a computer cluster. The method includes managing resources associated with an associated computer, the associated computer being one of a plurality of computers in the computer cluster. The method also includes managing locks on data stored on a plurality of associated data nodes coupled to the associated computer, wherein the associated data nodes are data nodes of a plurality of data nodes in the computer cluster. The method also includes specifying logical connections for the plurality of associated data nodes.

Abstract: An information retrieval system and method are provided for minimizing the number of blocks searched in a cell before recording a new record in the table and determining which block can be assigned if a table has space available to store a new record in the case an additional block should be associated with a cell. Dimensions for a table are identified, and at least one block in the table is associated with a dimension value for each dimension, where each block comprises contiguous storage pages. The block can be further associated with a cell; this associated cell has a unique combination of dimension values comprising an dimension value for each of the dimensions. A unique associated bit list for each dimension value for each dimension has a unique corresponding list entry for each block associated with that dimension value, and a unique associated bit list for each cell has a unique corresponding list entry for each block associated with that cell.

Abstract: Embodiments of the invention provide a method for regaining memory consistency after a trap via transactional memory. Transactional memory and a transactional memory log are used to undo changes made to memory from a transaction start point up to the point of a trap event. After the trap event is processed, and the changes are rolled back, the program can resume execution at the beginning of the transaction.

Abstract: A method for implementing a set of database management components in a distributed database management system, the distributed database management system being implemented on a computer cluster. The method includes managing resources associated with an associated computer, the associated computer being one of a plurality of computers in the computer cluster. The method also includes managing locks on data stored on a plurality of associated data nodes coupled to the associated computer, wherein the associated data nodes are data nodes of a plurality of data nodes in the computer cluster. The method also includes specifying logical connections for the plurality of associated data nodes.

Abstract: An adaptive throttling system for minimizing the impact of non-production work on production work in a computer system is provided. The adaptive throttling system throttles production work and non-production work to optimize production. The adaptive throttling system allows system administrators to specify a quantified limit on the performance impact of non-production or utility work on production work. The throttling rate of the utility is then automatically determined by a supervisory agent, so that the utilities' impact is kept within the specified limit. The adaptive throttling system adapts dynamically to changes in workloads so as to ensure that valuable system resources are well utilized and utility work is not delayed unnecessarily.

Abstract: A method for implementing distributed database management system operations on a computer cluster. The method includes defining ownership relationships between a plurality of computers in the computer cluster and a plurality of data nodes in the computer cluster, wherein a distributed database management system operation can be directly carried out by a first computer only on those data nodes owned by the first computer. The method further includes monitoring database usage characteristics. The method further includes carrying out a re-architecture step in response to the database usage characteristics by redefining ownership relationships to improve the efficiency of the distributed database management system operations.

Abstract: A distributed database management system implemented on a cluster of computers. The cluster including disks organized as data nodes. The data nodes being locally connected to one or more computers in the cluster. The distributed database management system includes a distributed database manager layer having a lock manager, a resource manager, and an architecture manager. The lock manager serializes access to the data nodes in the cluster. The resource manager maintains a data representation of the resources of each computer in the cluster and makes the data available to other computers in the cluster to facilitate access to the resources by the other computers. The architecture manager defines logical ownership relationships between data nodes and computers in the cluster to permit the architecture of the database to be dynamically reconfigured to provide improved performance.

Abstract: An adaptive throttling system for minimizing the impact of non-production work on production work in a computer system is provided. The adaptive throttling system throttles production work and non-production work to optimize production. The adaptive throttling system allows system administrators to specify a quantified limit on the performance impact of non-production or utility work on production work. The throttling rate of the utility is then automatically determined by a supervisory agent, so that the utilities' impact is kept within the specified limit. The adaptive throttling system adapts dynamically to changes in workloads so as to ensure that valuable system resources are well utilized and utility work is not delayed unnecessarily.

Abstract: A method, apparatus, and computer program product for storage pools with write atomicity. An abstraction manager enforces write atomicity and disallows options which are inconsistent with write atomicity. The abstraction manager constructs through a physical device interface a logical continuous view of a storage pool in a manner consistent with write atomicity. Applications collect information specific to write atomicity from the abstraction manager through an application interface.

Abstract: distributed database management system implemented on a cluster of computers. The cluster including disks organized as data nodes. The data nodes being locally connected to one or more computers in the cluster. The distributed database management system includes a distributed database manager layer having a lock manager, a resource manager, and an architecture manager. The lock manager serializes access to the data nodes in the cluster. The resource manager maintains a data representation of the resources of each computer in the cluster and makes the data available to other computers in the cluster to facilitate access to the resources by the other computers. The architecture manager defines logical ownership relationships between data nodes and computers in the cluster to permit the architecture of the database to be dynamically reconfigured to provide improved performance.