Efficient data retrieval from databases is a significant issue of the design of persistent systems. We propose an aspect oriented persistent system named AspectualStore. AspectualStore opens up its data retrieval mechanism so that developers can customize it in an aspect for performance optimization. The aspect controls the generation of SQL queries and minimizes the number of round-trips. It can also apply the customization only when the dynamic behavior of data accesses matches given patterns. This customization based on dynamic contexts is useful in practice and it needs aspectoriented programming. Traditional object-oriented programming is not appropriate although it can manage the customization based on static structures, such as customization for a particular class of data. Categories and Subject Descriptors D.2.11 [Software Architectures]: Domain-specific architectures General Terms Languages, Design Keywords Aspects, persistence, performance, databse