Abstract: A source database system sends information to a destination database system, and each database system generates a separate set of sequence information. A mapping is maintained between the two sets of sequence information. Using the mapping, the destination database system may be used to restore changes lost at the source database system without reinstating the source database. Additionally, queries associated with a particular point in a sequence associated with the sequence information of the source database may be redirected to the destination database, and the destination database system may serve as a logical standby for the source database system. A variety of methods of maintaining and/or extracting the mapping information are disclosed.

Abstract: Techniques for replicating a database object of a relational database managed by a database system from a first node on a network to a second node on the network include determining that the database object on the first node includes a user-defined object. A first routine of the database system is invoked. The first routine performs the step of copying the database object to the second node of the network. The first routine copies a name of a user-defined defined type of the user-defined object from the first node to the second node. The first routine also copies a first definition of the user-defined type from the first node to the second node. The first routine then copies a second definition of the database object from the first node to the second node. The second definition includes the name of the user-defined type. These techniques provide the benefits of peer-to-peer replication in a distributed database to users of object-relational databases that including user-defined objects.

Abstract: Approaches described herein may be used for provisioning of databases that requires a bulk transfer of data within a distributed computing environment, such as a grid. The approaches do not require the manual intervention of a DBA to, for example, transfer a tablespace between the file systems of operating systems. Instead, the tablespaces may be provisioned automatically and dynamically by a grid computing system whenever it determines the need to dynamically provision a database. In addition, as copies of tablespaces are provisioned, synchronization mechanisms can also be automatically provisioned to keep the tablespaces and their copies in sync.

Abstract: A method, system, and computer program product for transmitting a redo stream from a database to one or more distributed database systems, upon which applications that process the redo stream are implemented, and which maintains the data dictionaries by replicating the multiple versions of the schema objects to data dictionaries in the distributed database systems. A method of maintaining a multi-version data dictionary comprises the steps of generating a logical redo stream, inserting procedure calls to be used to populate the multi-version data dictionary into the generated logical redo stream, transmitting the logical redo stream to the multi-version data dictionary, and executing the procedure calls at the multi-version data dictionary to populate the multi-version data dictionary.

Abstract: In some messaging system architectures, messages can cycle back to the originator of a message, who may then propagate the message, causing the cycle to be repeated. Described herein are techniques that use rules and fields in a redo log, to manage message flows such that undesired cycles are prevented. The techniques may be used in messaging systems that have various topologies.

Abstract: Described herein are various approaches that allow rules to be used to specify actions, that alleviate the complexity and burden of developing and maintaining rules in a rules-based messaging system, and that provide more efficient ways of evaluating rules. The approaches allow rules to specify user-defined transformation functions for transforming messages, to specify when and how to perform row migration, and to specify other types of actions. Rules are grouped into rule sets. Several types of rule sets, referred to as positive and negative rule sets, allow users to use rules that are less complex to develop and maintain. Rule sets are evaluated more efficiently by attempting to evaluate the rule set with less information than is needed to evaluate all the rules in the rule set. Also, the results of rules evaluations that are based on a set of values are cached for later retrieval.

Abstract: Described herein are various approaches that allow rules to be used to specify actions, that alleviate the complexity and burden of developing and maintaining rules in a rules-based messaging system, and that provide more efficient ways of evaluating rules. The approaches allow rules to specify user-defined transformation functions for transforming messages, to specify when and how to perform row migration, and to specify other types of actions. Rules are grouped into rule sets. Several types of rule sets, referred to as positive and negative rule sets, allow users to use rules that are less complex to develop and maintain. Rule sets are evaluated more efficiently by attempting to evaluate the rule set with less information than is needed to evaluate all the rules in the rule set. Also, the results of rules evaluations that are based on a set of values are cached for later retrieval.

Abstract: A digital processor and method for performing mathematical division in which performance degradation is mitigated by avoiding left shift and append (14) on the output of an ALU using pre-shift and append (18, 22) of the feedback from the quotient and remainder storage element (R, Q).

Abstract: Schema evolution involves defining flavored object groups. Specifically, related collections of replicated tables and other database objects, which are defined as belonging to an object group, are given different “flavors.” A flavor describes different subsets of the objects and even different subsets of the columns in the master tables. In one embodiment, when one site in a distributed database system propagates changes to a replicated database object, the current flavor for the site is also transmitted, so that the destination site can make the necessary adjustments in the uploaded changes by dropping the values for obsolete columns and using default values for new columns.

Abstract: There is disclosed a digital processor having an arithmetic unit and a zero detection circuit and a method of performing zero detection in a digital processor in which a zero detection circuit is connected to the input of the arithmetic unit rather than being connected to the output thereof as is conventional. This enables testing the input to the arithmetic unit independently of the arithmetic unit itself so as to detect when the output value from the arithmetic unit is zero. The result is to take the delay of the zero detection circuit out of the critical processing path.

Abstract: In digital processing, a method and circuit for implementing at least one of a maximum and a minimum instruction between a source operand and a destination operand in which an arithmetic operation is performed using the source and destination operands to generate a result and the storage of data in a destination storage is controlled in accordance with the sign of the source operand, the sign of the destination operand and the sign of the said result.