In high-dimensional query processing, the optimization of the logical page-size of index structures is an important research issue. Even very simple query processing techniques such as the sequential scan are able to outperform indexes which are not suitably optimized. Page-size optimization based on a cost model faces the problem, that the optimum not only depends on static schema information such as the dimension of the data space but also on dynamically changing parameters such as the number of objects stored in the database and the degree of clustering and correlation in the current data set. Therefore, we propose a method for adapting the page size of an index dynamically during insert processing. Our solution, called DABS-tree, uses a flat directory whose entries consist of an MBR, a pointer to the data page and the size of the data page. Before splitting pages in insert operations, a cost model is consulted to estimate whether the split operation is beneficial. Otherwise, the sp...