Abstract: Techniques for logging data pertaining to the operation of a data stream processing server. In one set of embodiments, logging configuration information can be received specifying a functional area of a data stream processing server to be logged. Based on the logging configuration information, logging can be dynamically enabled for objects associated with the functional area that are instantiated by the data stream processing server, and logging can be dynamically disabled for objects associated with the functional area that are discarded (or no longer used) by the data stream processing server. In another set of embodiments, a tool can be provided for visualizing the data logged by the data stream processing server.

Abstract: Techniques for logging data pertaining to the operation of a data stream processing server. In one set of embodiments, logging configuration information can be received specifying a functional area of a data stream processing server to be logged. Based on the logging configuration information, logging can be dynamically enabled for objects associated with the functional area that are instantiated by the data stream processing server, and logging can be dynamically disabled for objects associated with the functional area that are discarded (or no longer used) by the data stream processing server. In another set of embodiments, a tool can be provided for visualizing the data logged by the data stream processing server.

Abstract: Techniques for facilitating communication between one or more client applications and an event processing server. In one set of embodiments, a framework is provided that enables a client application to communicate with an event processing server via a standard database connectivity API, such as Java Database Connectivity (JDBC).

Abstract: Techniques for facilitating communication between one or more client applications and an event processing server. In one set of embodiments, a framework is provided that enables a client application to communicate with an event processing server via a standard database connectivity API, such as Java Database Connectivity (JDBC).

Abstract: Techniques and systems are disclosed for directly storing semistructured data in a database. According to one aspect, a client application reads data that comprises instances of a parent type. The client application invokes routines associated with the parent type. An array is created for storing instances of the parent type. These routines invoke routines associated with a child type of the parent type. An array is created for storing instances of the child type. The arrays are populated with values specified in the data. According to one aspect, some columns of the arrays may be populated with other values to be stored in hidden columns of database tables. The client application converts the arrays into a data stream that conforms to the format of the database's data blocks. The client application then streams the data to a database server, which writes the data blocks directly into one or more data blocks in the database.

Abstract: A method and apparatus for sharing state information among a plurality of servers is provided. A first server receives a request to perform a file operation, such as a NFS file system operation. Thereafter, the first server updates state information to reflect a change in state associated with processing the request. The first server then causes state update information, which identifies the change in state that was made at the first server, to be propagated to a second server. The second server updates state information, stored at the second server, to reflect the change in state associated with processing the request at the first server. Advantageously, a client may send a series of stateful file operations to either the first server or the second server, even if processing any one of the stateful file operation requests requires knowledge of the state of processing prior requests in the series of requests.

Abstract: Techniques for managing memory usage of a processing system by spilling data from a memory to a persistent store based upon an evict policy are provided. A triggering event is detected. In response to the triggering event and based on the evict policy, it is determined whether data from the memory of the processing system is to be spilled to the persistent storage. The determination is made by comparing a level of free memory of the processing system with a threshold specified by the evict policy. The data is evicted from the memory.

Abstract: Techniques for managing memory usage in a processing system are provided. This may be achieved by receiving a data stream including multiple tuples and determining a query plan that was generated for a continuous query applied to the multiple tuples in the data stream. The query plan may include one or more operators. Before scheduling an operator in the query plan, it is determined when an eviction is to be performed based a level of free memory of the processing system. An eviction candidate is determined and a page associated with the eviction candidate is evicted from the memory to a persistent storage.

Abstract: Techniques for reducing the memory used for processing events received in a data stream are provided. This may be achieved by reducing the memory required for storing tuples. A method for processing a data stream includes receiving a tuple and determining a tuple specification that defines a layout of the tuple. The layout identifies one or more data types that are included in the tuple. A tuple class corresponding to the tuple specification may be determined. A tuple object based on the tuple class is instantiated, and during runtime of the processing system. The tuple object is stored in a memory.

Abstract: Techniques and systems are disclosed for storing instances of an opaque type in a database according to a direct path loading approach. According to one aspect, an opaque type implementor registers, with a loader application, routines that the opaque type implementor implements. In response, the loader application associates the opaque type with the routines. The loader application reads data that comprises instances of the opaque type. The loader application determines which routines are associated with the opaque type. The loader application invokes the routines, which create an array for storing instances of the opaque type and populate the array with values specified in the data. The loader application converts the array into a data stream that conforms to the format of the database's data blocks. The loader application then streams the data to a database server, which writes the data directly into data blocks in the database.

Abstract: A first continuous query is deleted from several continuous queries that are being executed, by performing different actions that depend on how resources are shared therebetween. As an example, a second continuous query is deleted if a view is referenced by the first continuous query, and if the view is built on the second continuous query, and if the view is not referenced by any query other than the first continuous query. Such deletion is followed by compiling the second continuous query, followed by updating the view to refer to a newly-compiled version of the second continuous query. As another example, if an operator in the first continuous query is not used by any other query, this operator is de-scheduled from execution, and any exclusively-owned resources are released. Also, data to be read by the operator and data generated by the operator, if present in shared resources, are deleted therefrom.

Abstract: A method and apparatus for reverting a resource to a prior state in time is provided. Changes are committed to a resource at a particular point in time. After the particular point in time, a request, which may be a file system operation request, to revert the resource to a state prior to the particular point in time is received at a database server. In response to the request, the resource is reverted to the state prior to the particular point in time. The current state of the resource ceases to reflect the plurality of changes. Advantageously, if a requestor creates an incorrect version of a resource, the changes made to a schema-based resource are not compatible with the schema, or the changes of multiple requesters are not compatible with each other, the resource may be reverted to the earlier point in time.

Abstract: Techniques for detecting patterns in one or more data or event streams. A pattern to be detected may be specified using a regular expression. Events received in a data stream are processed during runtime to detect occurrences of the specified pattern in the data stream. In one embodiment, a pattern type or class is determined for the specified pattern and pattern matching is performed using a technique selected based upon the type or class determined for the specified pattern.

Abstract: Techniques for detecting patterns in one or more data streams. A pattern to be detected may be specified using a regular expression. Events received in a data stream are processed during runtime to detect occurrences of the specified pattern in the data stream.

Abstract: Techniques for detecting patterns in data streams. A pattern to be detected may be specified using a regular expression. Events received in data streams are then processed during runtime to detect occurrences of the pattern specified by the regular expression in the data stream. If the pattern to be matched belongs to a certain predetermined class of patterns, then a pattern matching technique that is customized for that class of patterns is used during the runtime events processing.

Abstract: A computer is programmed to process a continuous query that is known to perform a new aggregation on one or more stream(s) of data, using one or more other aggregations on the stream(s). The computer creates an operator to execute the continuous query, and schedules the operator for execution in a specific order. In several embodiments, the computer determines the order based on dependency of the new aggregation on other aggregation(s), and on the order of performance of the other aggregation(s). The new aggregation is scheduled for performance after performance of each of the other aggregations. The computer is further programmed to pass results of the other aggregations to the new aggregation, by execution of a predetermined function. Support for use of the other aggregations results within the new aggregation eliminates redundant computation of the other aggregations within the new aggregation. The new aggregation may be user defined or built-in.

Abstract: A method and apparatus for processing a file system operation at a database server is provided. A request to perform a file system operation on a resource stored in a database is received at a database system. The request may be implemented using the NFS protocol. The request may include state identification data that identifies state information associated with the request. State information associated with the request is retrieved within the database system based on the state identification data. State information is information that describes the operational state of the requestor for a particular file. The request is then processed based, at least in part, on the state identification. File system operations may be processed a database management system to access any data, such as a file, relational data, and object-relational data.

Abstract: A method and apparatus for processing path-based database operations is provided. According to one aspect, a “parent row ID” column is added to a directory links table. For each row in the table, the value of the “parent row ID” column indicates the row ID, in the table, of the node that is that row's node's parent in the file hierarchy. To determine whether a particular node is within a specified path of the file hierarchy, the particular node's pathname is derived by visiting child-to-parent links indicated in the table and prepending, to the front of a pathname being constructed for the particular node, node names indicated in the visited rows. Each parent node's row in the directory links table is located using the “parent row ID” column of the child node's row. The resulting pathname is compared with the specified path to determine whether the particular node exists therein.

Abstract: A method and apparatus for performing file system operations involving a link is provided. A request to perform a file system operation involving a link is received from a client at a database server. The link may establish a relationship a source resource has to a target resource. The source resource and the target resource may be stored within a repository implemented by a storage medium, such as a database. The database server may perform the file system operation by storing, in the database, one or more link records that identifies the link between the first resource and the second resource. File system operations, such as a NFS file system operation, which involve links may be performed at a database management system.

Abstract: A method and apparatus for providing file system operation locks at a database server is provided. A database server may employ database locks and file system operation locks in servicing requests from consistent requestors and inconsistent requesters. A database lock is a lock that is obtained in response to performing a database operation, and the database lock is released when the database operation has successfully completed. A file system operation lock is a lock that is obtained in response to performing an OPEN file system operation, and the file system operation lock is released when a CLOSE file system operation is performed. The database server may use a temporary copy of the resource, which reflects all the current changes that have been made to the resource by database operations, in servicing consistent requestors, and may use the original version of the resource in servicing inconsistent requesters.