A paternisacomm on solution to aproblem that occurs in many different contexts. Patterns capture expertknowledge about “best practices” in software design in a form that allows that knowledge to bereused andappliedin the designofmanydifferent types of software. Antipatterns are conceptually similar to patternsinthat they document recurring solutions tocom m on design problem s. They areknown as antipatterns becausetheiruse (ormisuse) producesnegativeconsequences. Antipatterns document comm onmistakes madeduring software development aswellas theirsolutions.

W hile both patternsandantipatternscanbe foundin the literature, they typically do not explicitlyconsider performance consequences. Thispaper explores antipatterns from aperformance perspective. W e discuss performance problems associated with one well-known design antipattern and show how to solve them. W alsopropose threenew performanceantipatternsthatoften occur in software systems.