Abstract: Disclosure of approaches for processing database transactions against a database. In one approach, a first transaction is received that specifies an operation for changing state of a first record stored in a first database page. In processing the operation, the state of the record is changed, and information is stored in a companion page. The information includes a transaction identifier, data describing the specified operation, a page identifier of the first page, a before look and an after look of the first record for an update operation, and an after look of the first record for an insert operation. In response to a commit of the first transaction, a process determines whether a second transaction, that specifies a change in state for a second stored in the first page, is in-process. In response to determining that the second transaction is in process, the companion page is stored in an audit trail.

Abstract: Various approaches for processing a B+ tree data structure are described. In one approach, in a first transaction a first insert operation to a first data page of a first index page in the B+ tree data structure is detected, and then it is determined whether performing the first insert operation would block a second insert operation in a second transaction concurrent with the first transaction. At least one empty second data page is created in response to determining that the second insert operation would be blocked by the first insert operation. The B+ tree data structure is updated to include the at least one second data page in the B+ tree data structure, and the updated index pages and second data page are committed to retentive storage. Thereafter, the first insert can be completed.

Abstract: Various approaches for managing storage for data objects. In one approach, data describing a plurality of allocation control areas are stored. Each allocation control area references a respective set of free pages that are available for allocation for storing data objects. In response to a request to delete a data object, a non-blocking exclusive lock is sought on an initial one of the allocation control areas. If the lock is granted, each page having data of the data object is returned to the respective set of free pages of the initial one of the allocation control areas. If the lock is denied, another one of the allocation control areas to which a non-blocking exclusive lock can be granted is determined, and each page is returned to the respective set of free pages of the other one of the allocation control areas.

Abstract: Various approaches for processing a B+tree data structure of a database are disclosed. In one approach a method determines a pattern of multi-column key values. In response to an insert transaction into the database that requires a new index page and before performing the insert transaction, the method generates a plurality of new multi-column key values based on the pattern and stores one or more of the plurality of multi-column key values in one or more new index pages. Before performing the insert, the method further commits to retentive storage of the one or more new index pages and new data pages as linked to the B+tree. After committing the one or more new index pages and new data pages, the method then proceeds to processes and commits the insert transaction.

Abstract: Various approaches for adding data items to a database are described. In one approach, a method includes receiving a plurality of data items; each data item is to be stored under a unique primary key in the database. In response to each received data item, one of a plurality of fragment builders is selected and the data item is provided as input to the selected fragment builder. The fragment builders operate in parallel to create respective pluralities of B-tree fragments from the input data items. The B-tree fragments are merged into a single B-tree of the database, which is then stored.

Abstract: A system and method for managing a database is provided. The system and method includes logic that supports an atomic synchronization operation initiated by execution of a single synchronization statement. This operation utilizes a single call to a database management system to transform a database table from a first unknown state to a known state that contains a specified target record containing one or more specified data values. The first unknown state may be a state that already contains the target record, or may instead be a state that does not contain the record. In the former instance, a record containing one or more of the data values is created, and in the latter instance, the existing record is updated. A one-step locking mechanism is performed in conjunction with the operation to prevent the occurrence of deadlock and to minimize the number of required lock requests.

Abstract: Disclosure of approaches for processing database transactions against a database. In one approach, a first transaction is received that specifies an operation for changing state of a first record stored in a first database page. In processing the operation, the state of the record is changed, and information is stored in a companion page. The information includes a transaction identifier, data describing the specified operation, a page identifier of the first page, a before look and an after look of the first record for an update operation, and an after look of the first record for an insert operation. In response to a commit of the first transaction, a process determines whether a second transaction, that specifies a change in state for a second stored in the first page, is in-process. In response to determining that the second transaction is in process, the companion page is stored in an audit trail.

Abstract: A system and method is provided for inserting an ascending or descending sequence of data records into a database table represented by a tree structure. A search is performed to locate a node of the tree that includes the insertion point for a record in the sequence. If the node must be divided to store the record, it is determined whether division of the node at the insertion point will prevent a subsequently received record in the sequence from being stored on the same node with other records in the sequence irrespective of the storage space available on that node. If so, the node division is performed so that a record that is not in the sequence but that is adjacent to the insertion point is maintained on the same node as the other records in the sequence.

Abstract: Various approaches for capturing context data in a data processing arrangement are described. In one approach, a method controls shared access to an object for a plurality of requestors. An access control routine receives an access control request from a first routine of one of the requestors. The access control request specifies a type of control over access to the object and specifies a role descriptor that describes a processing context in the first routine of the requested access control to the object. The context is not visible to the access control routine without the role descriptor. The method determines whether the type of control can or cannot be immediately granted to the requestor. If the type of control cannot be immediately granted to the one of the requestors, the specified type of requested control and role descriptor are stored by the access control routine.

Abstract: Various approaches for generating key values in a database that is shared in a multi-host data processing arrangement. According to an example method, a shared sequence control structure contains a next key value. Mutually exclusive update access to the sequence control structure is provided for a plurality of instances of a database management system (DBMS) executing on the multi-host data processing arrangement. For a request for a new key value for a database record, a temporary copy of the next key value from the sequence control structure is stored, the sequence control structure is updated with a new next key value, and temporary copy of the next key value is stored as the new key value of the database record.

Abstract: Various approaches for processing a B+ tree data structure are described. In one approach, in a first transaction a first insert operation to a first data page of a first index page in the B+ tree data structure is detected, and then it is determined whether performing the first insert operation would block a second insert operation in a second transaction concurrent with the first transaction. At least one empty second data page is created in response to determining that the second insert operation would be blocked by the first insert operation. The B+ tree data structure is updated to include the at least one second data page in the B+ tree data structure, and the updated index pages and second data page are committed to retentive storage. Thereafter, the first insert can be completed.

Abstract: Various approaches for processing a B+ tree data structure are described. In one approach, a first data record is deleted from the database as part of processing a first transaction. After removing the first data record, it is determined whether a first data page from which the record was removed should be merged. If the first data page is to be merged, merging of the data page is delayed until after the first transaction has been committed. After committing the first transaction, a nested transaction is initiated to merge of the first data page, and the nested transaction is committed after the data page has been merged.

Abstract: Bypassing loading of memory in accessing large data objects in a relational database. A relational database may include a plurality of first type data items and associated second type data items. In response to an update-type access request, requester memory is bypassed in writing to the relational database a second type data item referenced by a file location specified in the update-type request. In response to retrieve-type request, requester memory is bypassed in reading from the relational database a second type data item referenced in the retrieve-type request and writing the second type data item at a file location specified in the retrieve-type request.

Abstract: Various approaches for allocating storage for a file are disclosed. In one approach, in response to each call to allocate an available portion of storage, one of a plurality of allocation approaches is selected based on a value of a file attribute associated with the file. If a first one of the allocation approaches is selected, a portion of storage is selected for storage of data using an approach that emphasizes storage of data in sequential physical storage. If a second one of the allocation approaches is selected, a portion of storage using an approach that emphasizes maintaining concurrent access to the file.

Abstract: A system and method for building a hierarchical table is described. According to one embodiment, sorted data is stored within, or otherwise associated with, a newly created leaf node. The leaf node is then added to the table in a manner that ensures that after the addition is completed, all leaf nodes within the table will reside at a same level within the table hierarchy. Thus, the table is constructed in a balanced manner, and no re-balancing of the table is required after table construction has been completed. According to another aspect, a balanced table may be constructed incrementally such that users are allowed to access data stored within the table while additional, related data is added to a second table that is later merged with the table. This incremental approach may adapted to construct unbalanced, as well as balanced, tables.

Abstract: A system and method for managing multiple partitions of a database are disclosed. According to one embodiment, each partition contains a subset of all records of the database, and is respectively associated with a secondary index B-tree, and a primary key B-tree. To retrieve a data record from the database, a partition is selected and a search is initiated on the associated secondary index B-tree for one or more records having a desired secondary index value. If records are so located, a primary key value obtained from one of the records is used to search the associated primary key B-tree to locate the data. In some cases, the search of the secondary index B-tree may not find the desired secondary index value within the selected partition. In these instances, pointers directed to one or more other partitions are used to locate records containing the desired secondary index value.

Abstract: Methods of detecting overflow and/or underflow events are provided. The methods are preferably incorporated into a high-level programming language, but this is not necessary. In one embodiment, an increasing function that may cause overflow for a data element having a value is performed on a surrogate variable having the same value as the data element. The variable is then compared to the value to determine whether the variable, after the function is performed, is greater than the value. If the value is greater than or in some cases equal to the variable, an overflow has occurred. If the value is less than the variable, no overflow has occurred. Additional embodiments determine whether an underflow occurs with a decreasing function in similar fashion, and the function may be performed on either the variable or the value.

Abstract: A system and method for managing binary large objects in a database are described in various embodiments. A database management system manages a database table having a plurality of rows of data. Each row includes one or more fixed-length data elements and one or more object identifiers that reference and are associated with respective binary large objects. An object handler coupled to the database management system, the object handler configured and arranged to store each binary large object in a section of contiguous storage referenced by the associated identifier, manages binary large objects.

Abstract: This disclosure relates to a computer implemented method that allows continued use of data files containing data encoded in a first coded character set while the data is gradually transliterated to a second coded character set. An intermediate coded character set is created that includes the required character symbols and associated character codes of the first coded character set and the corresponding pairs of character symbols and character codes from the second coded character set. The intermediate coded character set facilitates continued access to the data files which, during the process of gradual migration, will contain first coded character set character codes and second coded character set character codes. The intermediate coded character set further allows application software to selectively transliterate data encoded under the first coded character set to second coded character set character codes.