摘要:
A method and mechanism for identifying one or more transactions that have modified or created an object in a database system. Also disclosed is a method and mechanism to compensate for the effects of a transaction in a database system is disclosed. The disclosed approach can be applied to perform auditing for changes and/or transactions in a database system and for identifying the scope of changes and data accesses made by a transaction in the system.
摘要:
A method and mechanism for identifying one or more transactions that have modified or created an object in a database system. Also disclosed is a method and mechanism to compensate for the effects of a transaction in a database system is disclosed. The disclosed approach can be applied to perform auditing for changes and/or transactions in a database system and for identifying the scope of changes and data accesses made by a transaction in the system.
摘要:
A method and mechanism of accessing segments in data storage systems is disclosed. In one embodiment, extents in a segment are coalesced into groups based on the data storage device each extent is stored on. Rather than submit an I/O operation for each extent, a single I/O operation is submitted for each group of extents.
摘要:
A fact table is set up without any dimension columns. The data in the table is ordered according to an order corresponding to the ordering of the dimensions. The table is divided into segments corresponding to contiguous portions of data. The portions of the table containing non-null values for the measures are placed into the segments. The size of the segments and the location segments may be determined according to the density of discontinuities in the data. An indexed organized table is used to determine the beginning and end of each segment of the table, the locations of the discontinuities in the data, and to facilitate accessing the measures of the table.
摘要:
A method and mechanism to compensate for the effects of a transaction in a database system is disclosed. Also disclosed is a method and mechanism for identifying one or more transactions that have modified or created an object in a database system. The disclosed approach can be applied to perform auditing for queries in a database system and for identifying the scope of changes and data accesses made by a transaction in the system.
摘要:
A method and mechanism for tracking dependencies at low granularity levels in a database system is disclosed. An embodiment utilities commit time values at low granularity levels which are associated with structures in a database system. Those associated commit time values are used to compute dependency values.
摘要:
Embodiments of the present invention include a method for performing a data uniqueness check in a set of sorted data blocks comprising accessing data to be inserted into the set of sorted data blocks, determining a proper data block of the set of sorted data blocks for which the data to be inserted should be located based on a first sorting key. The method further includes examining the proper data block for an existing data entry and if the proper data block is empty, the method further includes inserting the data to be inserted into the proper data block of the set of sorted data blocks.
摘要:
Embodiments of the present invention include a method for performing a data uniqueness check in a set of sorted data blocks comprising accessing data to be inserted into the set of sorted data blocks, determining a proper data block of the set of sorted data blocks for which the data to be inserted should be located based on a first sorting key. The method further includes examining the proper data block for an existing data entry and if the proper data block is empty, the method further includes inserting the data to be inserted into the proper data block of the set of sorted data blocks.
摘要:
Techniques for managing changes in a computer system include storing, in a storage space, undo information for removing changes that are being made by entities. The undo information for each entity is stored in a segment of multiple segments within the storage space. Usage of the storage space by the entities is monitored. The number of segments in the plurality of segments or the sizes of the plurality of segments or both are adjusted automatically based on the usage. These techniques allow a resource to be recycled and allocated for new uses by other entities in a computer system dynamically based on usage. These techniques do not burden a human administrator with partitioning the resource and then penalize the administrator and users by generating errors when the partitions do not match usage.
摘要:
Techniques for managing, within a computer system, a resource that is reusable by a plurality of entities include establishing a minimum period of time for retaining an amount of the resource after completion of use of the resource by an entity. A first amount of the resource is allocated to a first entity. After allocating the first amount to the first entity, the first amount is prevented from being allocated to a second entity before the minimum period of time expires after the first entity completes use of the first resource. These techniques allow resources to be recycled and allocated for new uses by other entities in a computer system, but also guarantee the resources are retained in a given state for consistent use by other entities, even after the entity terminates that first had the resource allocated.