Abstract: A method and apparatus queries a table in a database where the table includes at least one column declared to be sparse. A binary large object may be used to store the sparse column data. The object includes a column-id and column-value pair for each non-null value. To answer a query with a constraint on a sparse column, the object is searched for one or more column ids to obtain the column values. Rows whose column values match a constraint are returned. In another embodiment, an internal table is used. Each tuple in the internal table has a column id and a value array indexed by an ordinal row number. To answer a query with a constraint on a sparse column, the column value in the internal table is found and matched against the constraint. If the match is successful, the index of the column value in the internal table is returned.

Abstract: Systems, methods, and other embodiments associated with bi-temporal user profiling are described. An event is detected that occurs at a valid event time. In response to the event, a repository is accessed that stores data describing one or more user profiles that include a profile record valid time period specifying a time at which the given profile record is valid. A prior user profile record is retrieved that has a profile record valid time period that overlaps with the valid event time. An updated user profile record is created based, at least in part, on the event. The updated user profile record is saved with the valid event time demarcating the start of a profile valid time period. The prior user profile with the valid event time demarcating the end of the profile record valid time period is also saved for subsequent processing.

Abstract: Data can be categorized into facts, information, hypothesis, and directives. Activities that generate certain categories of data based on other categories of data through the application of knowledge which can be categorized into classifications, assessments, resolutions, and enactments. Activities can be driven by a Classification-Assessment-Resolution-Enactment (CARE) control engine. The CARE control and these categorizations can be used to enhance a multitude of systems, for example diagnostic system, such as through historical record keeping, machine learning, and automation. Such a diagnostic system can include a system that forecasts computing system failures based on the application of knowledge to system vital signs such as thread or stack segment intensity and memory heap usage. These vital signs are facts that can be classified to produce information such as memory leaks, convoy effects, or other problems.

Abstract: Systems, methods, and other embodiments associated with bi-temporal user profiling are described. An event is detected that occurs at a valid event time. In response to the event, a repository is accessed that stores data describing one or more user profiles that include a profile record valid time period specifying a time at which the given profile record is valid. A prior user profile record is retrieved that has a profile record valid time period that overlaps with the valid event time. An updated user profile record is created based, at least in part, on the event. The updated user profile record is saved with the valid event time demarcating the start of a profile valid time period. The prior user profile with the valid event time demarcating the end of the profile record valid time period is also saved for subsequent processing.

Abstract: Systems, methods, and other embodiments associated with event processing are described. In one embodiment, a method includes detecting an event. The example method may also include analyzing the event to extract information about the user and processing a subsequent event in accordance with the extracted information about the user.

Abstract: Techniques are disclosed for creating and using a filter index in order to identify registered queries whose result sets are likely to have been changed by changes made to tables. The filter index entries are based on filter conditions. The filter conditions are created based on predicates contained in the registered queries. The filter conditions may include exclusive predicates and join predicates. Join predicates that join a table T1 with a table T2 may be instantiated by replacing references to table T2 with values extracted from table T2. Various techniques are described for recognizing situations in which a query can be included in, or excluded from, the set of likely-changed queries, without fully evaluating the filter conditions that correspond to the queries.

Abstract: Techniques are provided for freeing up resources before operations that change the resources have successfully completed. Resources are freed up by committing database transactions that perform portions of operations before the operations themselves have successfully completed. If the operations fail to complete successfully, then “compensation information” is used to remove the effects of the committed changes that were performed as part of the operation. Techniques are also provided for allowing database transactions to update values without retaining exclusive locks on those values. Operational constraints set forth conditions that must be satisfied before an update is allowed to proceed. If an attempt is made to update a particular value that has changes that may be undone, then the database server determines a plurality of “possible result values” for the particular value. If the possible result values satisfy the operational constraint conditions, then the update is allowed to proceed.

Abstract: Techniques are disclosed for sharing information in a wide variety of contexts. An information sharing system is described that allows both an explicit capture process and an implicit capture process to add information items to a staging area. Further, the information sharing system supports both implicit and explicit consumption of information items that are stored in said staging area. A rules engine is provided to allow users to create and register rules that customize the behavior of the capture processes, the consuming processes, and propagation processes that propagate information from the staging areas to designated destinations. Techniques are also described for achieving exactly-once handling of sequence of items, where the items are maintained in volatile memory. Techniques are also provided for recording DDL operations, and for asynchronously performing operations based on the previously-performed DDL operations.

Abstract: Techniques are disclosed for creating and using a filter index in order to identify registered queries whose result sets are likely to have been changed by changes made to tables. The filter index entries are based on filter conditions. The filter conditions are created based on predicates contained in the registered queries. The filter conditions may include exclusive predicates and join predicates. Join predicates that join a table T1 with a table T2 may be instantiated by replacing references to table T2 with values extracted from table T2. Various techniques are described for recognizing situations in which a query can be included in, or excluded from, the set of likely-changed queries, without fully evaluating the filter conditions that correspond to the queries.

Abstract: Techniques are provided for freeing up resources before operations that change the resources have successfully completed. Resources are freed up by committing database transactions that perform portions of operations before the operations themselves have successfully completed. If the operations fail to complete successfully, then “compensation information” is used to remove the effects of the committed changes that were performed as part of the operation. Techniques are also provided for allowing database transactions to update values without retaining exclusive locks on those values. Operational constraints set forth conditions that must be satisfied before an update is allowed to proceed. If an attempt is made to update a particular value that has changes that may be undone, then the database server determines a plurality of “possible result values” for the particular value. If the possible result values satisfy the operational constraint conditions, then the update is allowed to proceed.

Abstract: An extensible rules engine that uses database technology provides a rules evaluation service for applications external to the database server or database management system. Applications are able to utilize the rules engine to provide alternative behaviors based on information against which specified conditions are evaluated. A framework is provided for specifying data definitions that can be referenced by user-defined rules, through creation and use of an evaluation context. Application-specific data types can be defined by specifying data tables and/or variables that can be referenced by rules created for evaluation against data that is associated with the evaluation context. The data against which rules are evaluated can be provided as an in-memory object. A security model is provided in which the privilege to create rules according to a particular evaluation context is controlled by one privilege, whereas the privilege to access underlying tables or variables is controlled by another privilege.

Abstract: Described is an approach for recovering the failure of a transaction. According to the approach, a first change and a third change is made to a first resource and a second change is made to a second resource. The second change was made after the first but before the third. However, to recover the failure of the transaction, a recovery record for the third change is applied before the recovery record for the second change. Also described is an approach involving establishing links that link together a set of undo records that contain changes made to the particular resource. Also described is an approach for applying two or more undo records in parallel.

Abstract: A method for managing expressions includes receiving a first query that includes a first conditional expression. The first expression is then represented as data in a column of a table. A second query is received that specifies a first set of criteria, and the second query is executed to select data based at least on whether expressions in the column satisfy the first set of criteria. In an embodiment, the second query further specifies a second set of criteria, wherein executing the second query includes selecting data based on whether data in columns other than the expression column satisfy the second criteria. A special index is defined, which can be created on the column that stores the expressions as data, to filter large sets of expressions efficiently. A method of evaluating an expression set stored as data in a table classifies each predicate from each expression, and filters the expression set based on the predicate classification.

Abstract: Techniques for sharing information in a wide variety of contexts allows both an explicit capture process and an implicit capture process to add information items to a staging area. An information sharing system supports both implicit and explicit consumption of information items that are stored in the staging area. A rules engine allows users to create and register rules that customize the behavior of the capture processes, the consuming processes, and propagation processes that propagate information from the staging areas to designated destinations. Exactly-once handling of sequence of items is achieved for items maintained in volatile memory. DDL operations are recorded, and operations are asynchronously performed based on the previously-performed DDL operations.

Abstract: Described is an approach for recovering the failure of a transaction. According to the approach, a first change and a third change is made to a first resource and a second change is made to a second resource. The second change was made after the first but before the third. However, to recover the failure of the transaction, a recovery record for the third change is applied before the recovery record for the second change. Also described is an approach involving establishing links that link together a set of undo records that contain changes made to the particular resource. Also described is an approach for applying two or more undo records in parallel.

Abstract: A method for managing expressions includes receiving a first query that includes a first conditional expression. The first expression is then represented as data in a column of a table. A second query is received that specifies a first set of criteria, and the second query is executed to select data based at least on whether expressions in the column satisfy the first set of criteria. In an embodiment, the second query further specifies a second set of criteria, wherein executing the second query includes selecting data based on whether data in columns other than the expression column satisfy the second criteria. A special index is defined, which can be created on the column that stores the expressions as data, to filter large sets of expressions efficiently. A method of evaluating an expression set stored as data in a table classifies each predicate from each expression, and filters the expression set based on the predicate classification.

Abstract: An extensible rules engine that uses database technology provides a rules evaluation service for applications external to the database server or database management system. Applications are able to utilize the rules engine to provide alternative behaviors based on information against which specified conditions are evaluated. A framework is provided for specifying data definitions that can be referenced by user-defined rules, through creation and use of an evaluation context. Application-specific data types can be defined by specifying data tables and/or variables that can be referenced by rules created for evaluation against data that is associated with the evaluation context. The data against which rules are evaluated can be provided as an in-memory object. A security model is provided in which the privilege to create rules according to a particular evaluation context is controlled by one privilege, whereas the privilege to access underlying tables or variables is controlled by another privilege.

Abstract: A method and apparatus for removing changes made by a dead transaction is provided. According to the method, a first change is performed by the dead transaction prior to a second change. The first change made by the dead transaction is then undone prior to undoing the second change made by the dead transaction. According to another aspect of the invention, a method and apparatus for applying changes in redo records to make a particular resource reflect changes made to the particular resource in volatile memory before a failure is provided. The method includes establishing links that link together a set of redo records that contain changes made to the particular resource. The links are then followed to apply the changes contained in the set of redo records to cause the particular resource to reflect the changes made to the particular resource in volatile memory before the failure.

Abstract: A method and apparatus are provided for implementing a content-based publish-and-subscribe system in a relational database system. A subscriber may request for messages by using a query language supported by the database server. The queries are then used as subscription rules for determining whether an incoming message is to be sent to the subscriber. Evaluation of incoming messages against subscription rules involves a two-tier process. The first tier involves filtering out all the subscription rules that could not possibly apply to the incoming message. The second tier involves further evaluation of the incoming message, if needed, to determine which subscribers are to receive the incoming message. In another aspect of the embodiment, in cases where the publisher is the relational database system itself, queries that request for messages are not stored as subscription rules because publication of the messages is implicit.

Abstract: A method and apparatus are provided for implementing a content based publish-and-subscribe system in a relational database system. A subscriber may request for messages by using a query language supported by the database server. The queries are then used as subscription rules for determining whether an incoming message is to be sent to the subscriber. Evaluation of incoming messages against subscription rules involves a two-tier process. The first tier involves filtering out all the subscription rules that could not possibly apply to the incoming message. The second tier involves further evaluation of the incoming message, if needed, to determine which subscribers are to receive the incoming message. In another aspect of the embodiment, in cases where the publisher is the relational database system itself, queries that request for messages are not stored as subscription rules because publication of the messages is implicit.