9. A method for transformation rule profiling for a query optimizer of a database system, comprising: identifying a workload of queries including a plurality of database queries configured to be optimized by the query optimizer of the database system; finding an optimized query plan for a database query using a host set of transformation rules; removing individual transformation rules from a query plan generation, wherein one transformation rule is removed and checked at a time; generating a test query plan after the transformation rule has been removed from the host set of transformation rules; determining whether the test query plan is identical to the optimized query plan in the absence of the removed transformation rule; marking a transformation rule as relevant to a database query based on a changed test plan when the transformation rule has been removed; defining a relevance ratio of a selected rule for a workload of queries as a fraction of queries in the workload of queries where the selected rule is relevant to a query because removal of the transformation rule affects the optimized query plan; and selecting transformation rules with a relevance ratio that exceed a relevance threshold to be applied to queries using the query optimizer.
9. A method for transformation rule profiling for a query optimizer of a database system, comprising: identifying a workload of queries including a plurality of database queries configured to be optimized by the query optimizer of the database system; finding an optimized query plan for a database query using a host set of transformation rules; removing individual transformation rules from a query plan generation, wherein one transformation rule is removed and checked at a time; generating a test query plan after the transformation rule has been removed from the host set of transformation rules; determining whether the test query plan is identical to the optimized query plan in the absence of the removed transformation rule; marking a transformation rule as relevant to a database query based on a changed test plan when the transformation rule has been removed; defining a relevance ratio of a selected rule for a workload of queries as a fraction of queries in the workload of queries where the selected rule is relevant to a query because removal of the transformation rule affects the optimized query plan; and selecting transformation rules with a relevance ratio that exceed a relevance threshold to be applied to queries using the query optimizer. 12. The method as in claim 9 , wherein the relevance threshold is set to select transformation rules relevant to greater than a pre-defined percentage of queries.