Rule-based extendable query optimizer

摘要

A query is received which causes an initial data flow graph that includes a plurality of nodes that are used to execute the query is generated. Thereafter, the initial data flow graph is optimized using a model optimizer that includes an optimizer framework and an application programming interface (API). The optimizer framework provides logic to restructure the initial data flow graph and a rules engine for executing one or more optimization rules. The API allows for registration of new optimization rules to be executed by the rules engine. Execution of the query is then initiated using the optimized data flow graph. Related apparatus, systems, techniques and articles are also described.

主权项

1. A computer implemented method comprising:
receiving, via an application programming interface (API) of a calculation engine including a model optimizer having an optimizer framework, data comprising at least one optimization rule, the calculation engine executing on a calculation engine layer that interacts with a physical table pool and a logical layer, the physical table pool comprising physical tables containing data to be queried, and the logical layer defining a logical metamodel joining at least a portion of the physical tables in the physical table pool; registering, by the calculation engine, the at least one optimization rule for execution by a rules engine of the optimizer framework, wherein the optimizer framework assigns cost functions to at least a portion of optimization rules, the cost functions being used to determine when to execute a particular optimization rule; receiving, by the calculation engine, subsequently each query; generating, by the calculation engine, an initial data flow graph comprising a plurality of nodes specifying operations for executing the query; optimizing, by the calculation engine, the initial data flow graph using the rules engine, wherein at least one rule is applied to only a single node of the initial data flow graph, wherein a first subset of the operations are executed directly by the calculation engine and a second, different subset of the operations are transformed into a set of logical database execution plans, wherein each rule of the rules engine identifies one to N predecessors of corresponding start node from which optimization can be initiated, wherein N is an integer number, wherein said each rule specifies read and write operations to perform on corresponding nodes; and initiating executing of the query using the optimized data flow graph.