Systems and methods for improving the performance of a computer program, such as a database management system (DBMS), are provided. The methods involve identifying invariant intervals for variables inthe DBMS code, based on a Program Representation (PR). Program interactions within the DBMS and domain assertions are deduced, based on the PR and an Ecosystem Specification for the DBMS. One or morecandidate snippets are identified, based on the invariant intervals for variables in the DBMS code, the PR, one or more execution summaries associated with the DBMS, the deduced program interactionsand the deduced domain assertions. Spiffs are then generated, based on the one or more candidate snippets. Such spiffs include predicate query spiff, hash-join query spiff, aggregate spiff, page spiff, and string matching spiff. The DBMS code is modified based on the speccode generated from these spiffs.