Mack, M: Optimized Distributed DataStore Exchange

Virtualized web application servers within computational clouds, such as the Google App Engine, generally restrict resource usage and therefore provide limited, relationally none-complete query facilities only. This work investigates how scalable, reliable and a more powerful access to the App Engine Datastore can be accomplished and an Optimized Distributed Datastore Exchange (ODDSE) is presented. Being aware of the App Engine‘s resource restrictions ODDSE provides a reliable and failure safe query interface to transparently exchange data with the distributed Datastore using the query languages SQL or AmosQL. ODDSE wraps Datastore relations and utilizes the extensible database system Amos II to compensate for missing query facilities in Google‘s relationally none-complete query language GQL. Under the covers ODDSE furthermore implements an adaptive and reliable management of interactions with App Engine servers. For scalability and high performance the interaction is parallelized and continuously adapted. The performance of ODDSE is evaluated and compared to a similar system showing its considerably good results for both bulk uploading and query processing.