BasisGraph: Combining Storage and Structure Index for Similarity Search in Graph DB

Graph databases supporting retrieval based on structural similarity utilize structure indexes. A structure index is a data structure that indexes different structural features of member graphs. These features are typically extracted at insertion time. However, as the extraction of structural features may suffer from combinatorial explosion, the structure index takes long insertion time and large disk space. The member graphs cannot be modified, since even a simple structural modification may require re-extraction of structural features. The depth to which structural features were extracted during insertion, forms a hard limit on query precision, which cannot be changed at query time. In order to address these issues, a new model is introduced that combines the database graph storage and the structure index into one data structure. There is no need to extract structural features at insertion time, no hard limit on query refinement and graph modifications are supported naturally.