Abstract: Systems, methods and devices are provided for deploying data from an operational database with multi-version-concurrency-control, the method comprising: deriving a single SQL query statement for retrieving large amounts of related, heterogeneous data as output where the large amounts of data are internally self-consistent; transforming and decorating the single SQL query output to obtain deployment data; and transferring the deployment data to the deployment target.

Abstract: The estimate of the selectivity of a HAVING clause in an SQL query is carried out within a specified time constraint by determining a selectivity estimate for each member in a sample set of group sizes for the HAVING clause using a probabilistic model based on an assumed value distribution. The selectivity estimates for the groups in the sample set are used to interpolate estimates for all possible group sizes and the estimates are combined based on an assumed known group size distribution to provide an estimation of the selectivity for the HAVING clause. Different selectivity estimating approaches are used for each group size based on available time for estimating and on the estimated time to complete the estimate using different techniques.

Abstract: A system and process for evaluating the performance of an operational database system without interfering with the normal operation of the operational database system is described. The process involves the creation of a test database which contains the system catalogs of the operational database system as user tables. The test database is used to compile queries using these simulated system catalogs. The access plan generated by the compilation in the test database can then be used to evaluate the performance of the queries.

Abstract: A system and process for evaluating the performance of an operational database system without interfering with the normal operation of the operational database system is described. The process involves the creation of a test database which contains the system catalogs of the operational database system as user tables. The test database is used to compile queries using these simulated system catalogs. The access plan generated by the compilation in the test database can then be used to evaluate the performance of the queries.

Abstract: The estimate of the selectivity of a HAVING clause in an SQL query is carried out within a specified time constraint by determining a selectivity estimate for each member in a sample set of group sizes for the HAVING clause using a probabilistic model based on an assumed value distribution. The selectivity estimates for the groups in the sample set are used to interpolate estimates for all possible group sizes and the estimates are combined based on an assumed known group size distribution to provide an estimation of the selectivity for the HAVING clause. Different selectivity estimating approaches are used for each group size based on available time for estimating and on the estimated time to complete the estimate using different techniques.

Abstract: The invention provides a method and apparatus including a programming product for a parallel data processing system having a plurality of nodes interconnected by communication paths, in which one or more sets of data present at one or more source nodes of the system is required to be sent on a plurality of communication paths having communication buffers to selected nodes of the database system for processing, a system of communicating the data over the paths between the nodes to avoid deadlocking the processing system, including: accessing data from the one or more source nodes in subsets of the data; sending the subsets of data on a plurality of paths to the selected nodes of the processing system; if a path of the paths intended for the sending of one or more of the subsets of data becomes blocked, suspending the sending of subsets of the data on the path for a predetermined time period; if the blocked path becomes capable of accepting additional data before the predetermined time period has expired, resum