Abstract: A computer modifies data inside a database large object (LOB) of unknown structure without modifying other data in the remainder of the LOB. Insertion of new data at a specified location in the LOB does not require movement of existing data in the LOB. Instead, the computer is programmed to insert new data at a physical end of the LOB, and modify metadata based on the specified location. Similarly, deletion of existing data from a specified location in the LOB is performed without movement of other data in the LOB, by updating the metadata. The computer uses the metadata when reading from the LOB, so that the new data is automatically read whenever the specified location is accessed. The computer may optionally output a handle that is static, relative to other insertions and deletions, to identify specific data within the LOB, for use in building indexes on the LOB.

Abstract: One embodiment of the present invention provides a system that facilitates automatically organizing digital images using metadata which is embedded in the digital images. The system operates by receiving a digital image with embedded metadata, wherein the embedded metadata includes Global Positioning System (GPS) data. The system uses the embedded metadata, including the GPS data, to identify additional metadata associated with the digital image. The system then saves the digital image on a storage medium. In addition, the system saves the embedded metadata and the additional metadata on the storage medium in a searchable format.

Abstract: 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.

Abstract: An array update operation which specifies number of (row-identifier, value) pairs for updating rows in a table of a database is implemented as follows. A block-identifier of a block (on disk) that holds a row identified by a row-identifier in a specified pair is looked up using a database index, and the block-identifier thus found is stored in a structure. Use of a row-identifier to look up the corresponding block-identifier, and the storage of the block-identifier in the structure are repeatedly performed, for each of several specified pairs. Next, a vector read is performed, to read and store in a cache, each block identified by a block-identifier in the structure, and all the blocks that have been read are stored in the cache during a single function call. Thereafter, rows identified in specified pairs are modified, in blocks currently in the cache, using the values in the specified pairs.

Abstract: A method and apparatus for proactively allocating space to a logical layer of a database is provided. Allocation of space to a logical layer of a database is an expensive operation that should be minimized. The allocation of space includes discovering free space in all the higher layers in the logical storage hierarchy. It also includes cross-domain system calls and cleansing disk-write operations. In prior approaches, the allocation processes were triggered on-demand, only a certain logical layer was discovered to be at full capacity when an insert-row operation was attempted. In one embodiment of the invention, space needs are statistically predicted based on prior rates of space consumption. The database server pre-allocates space as needed, based on the statistical predictions. Rates of consumption are examined periodically.

Abstract: A framework for in-memory space management for content management database systems is provided. A per-instance in-memory dispenser is partitioned. An incoming transaction takes a latch on a partition and obtains sufficient block usage to perform and complete the transaction. Generating redo information is decoupled from transaction level processing and, instead, is performed when block requests are loaded into the in-memory dispenser or synced therefrom to a per-instance on-disk structure.

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 described to allow a query to be registered as a persistent stored entity within the database, and to generate notifications as and when the query result changes continuously as long as the query continues to be registered with the database. According to one aspect, for a table referenced in a query, a filter condition is generated based, at least in part, on a predicate of the query. Then, the database server determines whether the filter condition is satisfied by either a before image of a row, or an after image of the row, that was modified by a transaction. If the filter condition is satisfied by either the before image or the after image, then the query is added to a first set of queries whose result sets may have been affected by the transaction. From among the first set of queries, a second set of queries that have result sets that were actually affected by the transaction is determined. Notifications are then sent based on the second set of queries.

Abstract: One embodiment of the present invention provides a system for automatically classifying data in a database. During operation, the system receives and executes a database operation. Next, the system automatically determines if any data was modified as a result of executing the database operation. If so, for each data item that was modified, the system automatically determines if the data item is associated with a classification-rule. If so, the system automatically reclassifies the data item according to the classification-rule. If not, the system leaves a classification of the data item unchanged.

Abstract: Techniques for compressing branch nodes in an index are provided. The branch nodes may be part of a main index of a multi-level index that also includes one or more journal indexes. A Bloom filter may be generated and associated with, e.g., a branch node in the main index. The Bloom filter is used to determine whether, without accessing any leaf blocks, a particular key value exists, e.g., in leaf blocks associated with the branch node.

Abstract: Techniques for maintaining a cascading index are provided. In one approach, one or more branch node compression techniques are applied to the main index of a cascading index. In an approach, a Bloom filter is generated and associated with, e.g., a branch node in the main index. The Bloom filter is used to determine whether, without accessing any leaf blocks, a particular key value exists, e.g., in leaf blocks associated with the branch node. In an approach, a new redo record is generated in response to a merge operation between two levels of the cascading index. The new redo record comprises (a) one or more addresses of blocks that are affected by the merge operation, (b) data is that being “pushed down” to a lower level of the cascading index, and (c) one or more addresses of blocks that are written to disk storage as a result of the merge operation.

Abstract: A method and apparatus for asynchronously storing transaction information related to a transaction is provided. A client process executing on a client may initiate a transaction request with a server. The server processes the transaction, commits the transaction, and writes transaction information associated with the transaction to memory without durably storing the transaction information. Thereafter, the server processing the transaction returns a message to the client that the transaction has been committed. A server process, which performed the transaction, may be reassigned to commit new work. Additional information that may be useful for the client about the result of the transaction may be contained in the message. Next, transaction information stored in memory is durably stored. A log writer may be used to durably store the transaction information to a log file. The client is subsequently notified that the transaction information has been durably stored at a client listening process.

Abstract: A method and apparatus for data recovery are disclosed. A plurality of queries executing in a database system are tracked. A query with a longest duration is selected and undo retention duration is calculated for supporting the longest query.

Abstract: A method and apparatus for creating a target database on a target platform based on a source database on a source platform is provided. A target database is created on the target platform based on data, metadata (for example, data in the system tablespace and control files), and external objects (for example, password files and externally stored tables) comprised within the source database. Data and metadata stored in tablespaces of the source database are converted to the format compatible with the target platform. The conversion of the data and metadata may be performed either at the source database or the target database. Redo information and undo information of the source database are not copied from the source database to the target database. Certain files, e.g., a password files, and links to externally stored object may be recreated on the target database.

Abstract: A method and apparatus for updating databases are disclosed. In response to a flashback request, a database object is restored to a state as of a specified flashback time. The changes introduced into the database object are reversed in a sequence starting with a change introduced into the database object immediately before issuance of the flashback request and ending with a change introduced into the database object immediately after the specified flashback time.

Abstract: Past versions of data in a distributed database system comprising multiple databases and associated database servers are queried using temporal database access mechanisms, where a request for data in a past state from a “remote” database can be received at a “local” database server and relevant portions of the request are passed to the remote server for processing. The processing performed by the remote server includes returning the requested data in the specified past state to the local server, or at least with enough information to reconstruct the data into the past state.

Abstract: A computer is programmed to compress data of a database in response to database modification language (DML) statements generated by on-line transaction processing (OLTP) systems. In several embodiments, data that is initially added to a database block is left uncompressed until a predetermined condition is satisfied, which happens infrequently (relative to OLTP transactions on the block). When satisfied, the computer automatically compresses all uncompressed data in the block, which increases the amount of unused space in the block. New data is thereafter added uncompressed to the partially compressed block, until satisfaction of a predetermined condition whereby the partially compressed block is again compressed, i.e. re-compressed. Adding of new data to a partially compressed block and its compression are repeated unless another predetermined condition is met, in response to which the block is not further re-compressed, thereby to recognize a limit on the benefit from compression.

Abstract: A method and apparatus for updating databases are disclosed. In response to a flashback request, a database object is restored to a state as of a specified flashback time. The changes introduced into the database object are reversed in a sequence starting with a change introduced into the database object immediately before issuance of the flashback request and ending with a change introduced into the database object immediately after the specified flashback time.

Abstract: A framework for in-memory space management for content management database systems is provided. A per-instance in-memory dispenser is partitioned. An incoming transaction takes a latch on a partition and obtains sufficient block usage to perform and complete the transaction. Generating redo information is decoupled from transaction level processing and, instead, is performed when block requests are loaded into the in-memory dispenser or synced therefrom to a per-instance on-disk structure.

Abstract: Disclosed is a system and method for implementing space management for large objects stored in the computing system. According to some approaches, storage of large objects are managed by dynamically creating contiguous chunks of storage space of varying lengths. The length of each chunk may vary depending upon object size being stored, fragmentation of the storage space, available free space, and/or expected length of the object.