% This data is distributed under the terms of the Open Data Commons Attribution License (ODC-By) v1.0 - See more at: http://opendatacommons.org/licenses/by/1-0/ % All issues of Volume 3 % Volume 3, Issue 1, 2016 @Article{OJDB_2016v3i1n01_Menninghaus, title = {High-Dimensional Spatio-Temporal Indexing}, author = {Mathias Menninghaus and Martin Breunig and Elke Pulverm{\"u}ller}, journal = {Open Journal of Databases (OJDB)}, issn = {2199-3459}, year = {2016}, volume = {3}, number = {1}, pages = {1--20}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201705194635}, urn = {urn:nbn:de:101:1-201705194635}, publisher = {RonPub}, bibsource = {RonPub}, abstract = {There exist numerous indexing methods which handle either spatio-temporal or high-dimensional data well. However, those indexing methods which handle spatio-temporal data well have certain drawbacks when confronted with high-dimensional data. As the most efficient spatio-temporal indexing methods are based on the R-tree and its variants, they face the well known problems in high-dimensional space. Furthermore, most high-dimensional indexing methods try to reduce the number of dimensions in the data being indexed and compress the information given by all dimensions into few dimensions but are not able to store now - relative data. One of the most efficient high-dimensional indexing methods, the Pyramid Technique, is able to handle high-dimensional point-data only. Nonetheless, we take this technique and extend it such that it is able to handle spatio-temporal data as well. We introduce a technique for querying in this structure with spatio-temporal queries. We compare our technique, the Spatio-Temporal Pyramid Adapter (STPA), to the RST-tree for in-memory and on-disk applications. We show that for high dimensions, the extra query-cost for reducing the dimensionality in the Pyramid Technique is clearly exceeded by the rising query-cost in the RST-tree. Concluding, we address the main drawbacks and advantages of our technique.} } @Article{OJDB_2016v3i1n02_Werner, title = {Runtime Adaptive Hybrid Query Engine based on FPGAs}, author = {Stefan Werner and Dennis Heinrich and Sven Groppe and Christopher Blochwitz and Thilo Pionteck}, journal = {Open Journal of Databases (OJDB)}, issn = {2199-3459}, year = {2016}, volume = {3}, number = {1}, pages = {21--41}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201705194645}, urn = {urn:nbn:de:101:1-201705194645}, publisher = {RonPub}, bibsource = {RonPub}, abstract = {This paper presents the fully integrated hardware-accelerated query engine for large-scale datasets in the context of Semantic Web databases. As queries are typically unknown at design time, a static approach is not feasible and not flexible to cover a wide range of queries at system runtime. Therefore, we introduce a runtime reconfigurable accelerator based on a Field Programmable Gate Array (FPGA), which transparently incorporates with the freely available Semantic Web database LUPOSDATE. At system runtime, the proposed approach dynamically generates an optimized hardware accelerator in terms of an FPGA configuration for each individual query and transparently retrieves the query result to be displayed to the user. During hardware-accelerated execution the host supplies triple data to the FPGA and retrieves the results from the FPGA via PCIe interface. The benefits and limitations are evaluated on large-scale synthetic datasets with up to 260 million triples as well as the widely known Billion Triples Challenge. } } @Article{OJDB_2016v3i1n03_Koch, title = {XML-based Execution Plan Format (XEP)}, author = {Christoph Koch}, journal = {Open Journal of Databases (OJDB)}, issn = {2199-3459}, year = {2016}, volume = {3}, number = {1}, pages = {42--52}, url = {http://nbn-resolving.de/urn:nbn:de:101:1-201705194654}, urn = {urn:nbn:de:101:1-201705194654}, publisher = {RonPub}, bibsource = {RonPub}, abstract = {Execution plan analysis is one of the most common SQL tuning tasks performed by relational database administrators and developers. Currently each database management system (DBMS) provides its own execution plan format, which supports system-specific details for execution plans and contains inherent plan operators. This makes SQL tuning a challenging issue. Firstly, administrators and developers often work with more than one DBMS and thus have to rethink among different plan formats. In addition, the analysis tools of execution plans only support single DBMSs, or they have to implement separate logic to handle each specific plan format of different DBMSs. To address these problems, this paper proposes an XML-based Execution Plan format (XEP), aiming to standardize the representation of execution plans of relational DBMSs. Two approaches are developed for transforming DBMS-specific execution plans into XEP format. They have been successfully evaluated for IBM DB2, Oracle Database and Microsoft SQL.} }