Abstract: According to a present invention embodiment, a system conducts a scan on a database object index with one or more gaps. The system generates one or more combinations of values for the gaps within an index with respect to an operation. Each combination of values is generated by scanning the index based on a combination of one or more scan values, adjusting a value for a gap based on scan results, and adjusting the scan values for a succeeding scan based on the scan results to reduce a quantity of scans. The index includes at least two database object elements. One or more scans of the index utilizing the combinations of values are conducted to retrieve data from the database and accommodate each gap in the index. Present invention embodiments further include a method and computer program product for conducting the index scan.

Abstract: According to a present invention embodiment, a system conducts a scan on a database object index with one or more gaps. The system generates one or more combinations of values for the gaps within an index with respect to an operation. Each combination of values is generated by scanning the index based on a combination of one or more scan values, adjusting a value for a gap based on scan results, and adjusting the scan values for a succeeding scan based on the scan results to reduce a quantity of scans. The index includes at least two database object elements. One or more scans of the index utilizing the combinations of values are conducted to retrieve data from the database and accommodate each gap in the index. Present invention embodiments further include a method and computer program product for conducting the index scan.

Abstract: In a shared data system comprising one or more primary nodes and a plurality of secondary nodes, global lock manager on a primary node manages locks for shared resources by exchanging an abstract lock state with local lock managers on the secondary nodes. The abstract lock state includes a particular representation of all of the applications on the nodes that are requesting or are granted locks. The exchange of these particular lock states instead of individual requests improves performance by increasing concurrency and reducing off-machine communication. A global deadlock detector on a node detects and resolves global deadlocks, in conjunction with local deadlock detectors on the secondary nodes.

Abstract: A query pushdown system determines whether all, some or none of the query predicates of an object-oriented query received at an object level of a database may be executed in a relational level of the database. The determined query predicates are pushed down to the relational level and executed in the relational level. The results of the query execution are transferred to the object level. In addition, data sets corresponding to query predicates that could not be executed in the relational level are also transferred to the object level. Any results and data sets are applied to the remaining query predicates which are executed in the object level.