Ncr Corporation

Prasad Manikarao Deshpande

Jeffrey F Naughton

Karthikeyan Ramasamy

Amit Shukla

An &ldquo;active cache&rdquo;, for use by On-Line Anaytic Processing (OLAP) systems, that can not only answer queries that match data stored in the cache, but can also answer queries that require aggregation or other computation of the data stored in the cache.

Method for determining the computability of data for an active multi-dimensional cache in a relational database management system

An On-Line Analytic Processing (OLAP) system converts queries into an operator tree comprised of a plurality of operators, wherein each of the operators is independently executed. When an exception is detected in one or more of the independently executed operators, the exception is propagated to the remaining operators of the operator tree by recycling empty data pages, piggybacking the detected exceptions on the recycled data pages, and sending the recycled data pages both upstream and downstream in the operator tree to the remaining operators of the operator tree. The propagated exceptions are delivered to the remaining operators, without interrupting the operators, at one or more points at which the operator normally reads or writes data from its input stream. Finally, the operators are terminated using a depth-first traversal of the operator tree.

Efficient exception handling during access plan execution in an on-line analytic processing system

An &ldquo;active cache&rdquo;, for use by On-Line Analytic Processing (OLAP) systems, that can not only answer queries that match data stored in the cache, but can also answer queries that require aggregation or other computation of the data stored in the cache.

Active caching for multi-dimensional data sets in relational database management system

An On-Line Analytic Processing (OLAP) system computes complex expressions and aggregations in queries by re-using and sharing subparts of the expressions and aggregations. A dependency generation phase performed by the OLAP system identifies dependencies among metrics based on the expressions, aggregations, and other metrics used by the metrics. An access plan generation phase performed by the OLAP system generates an access plan based on the identified dependencies, wherein the access plan ensures that expressions, aggregations, and metrics are computed before they are needed, and that required values and intermediate results are passed up a tree structure of the access plan until they are used or consumed by some operator. An operator assignment phase performed by the OLAP system generates operators based on the access plan, and also generates project list expressions, aggregations to be computed in each operator, and input and output tuple types for each operator.

Shared computation of user-defined metrics in an on-line analytic processing system

An On-Line Analytic Processing (OLAP) system identifies a plurality of simultaneously computable moving aggregate functions in a query. The identified moving aggregate functions are then partitioned into sets that can be computed simultaneously based on equivalent sort expressions. Finally, the OLAP system generates an access plan that executes the partitioned sets simultaneously.

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Prasad Manikarao Deshpande