Recording lineage in query optimization

A computer system comprising:

• a processing system accessing computer program instructions that, when executed by the processing system, configures the computer system to be comprising:
• a database comprising a query optimizer having an input receiving an input query in a declarative query language and an output providing a query execution plan comprising instructions performed on the database, the query optimizer being configured to:
• receive stored information for an original query execution plan for the input query, the stored information including, for each application of a transformation used to produce an expression in the query execution plan, data indicative of the transformation applied and bindings for the transformation, the bindings indicating expressions input to the transformation;
• for each transformation to be applied to the input query, in response to the transformation being indicated by the stored information, applying the transformation, and otherwise avoiding transformations not used to generate expressions in the original query execution plan.

A computer-implemented process, performed by a computer comprising a processing system accessing computer program instructions that, when executed by the processing system, configures the computer to perform the process, comprising:

• receiving, in a query optimizer of a database, an input query in a declarative query language;
• receiving stored information for an original query execution plan for the input query, the stored information including, for each application of a transformation used to produce an expression in the original query execution plan, data indicative of the transformation applied and respective bindings for the transformation, the bindings indicating expressions input to the transformation;
• for each transformation to be applied to the input query, in response to the transformation being indicated by the stored information, applying the transformation used to generate the original query execution plan;
• and
• generating a query execution plan based on the applied transformations.