Abstract-Modern database management systems (DBMS) answer a multitude of complex queries on increasingly larger datasets. Given the complexities of the queries and the numerous design features, manual design is no longer an option. Instead, automatically designing the database is vital to maximize its performance and to reduce the total cost of ownership. For this purpose, commercial DBMS feature automated physical designers suggesting an efficient DB design by using the optimizer as a cost model. Unfortunately, consulting the optimizer is timeconsuming, an effect which is typically counter-acted by drastically pruning the search space, thereby potentially missing the optimal solution. Recently techniques cache the optimizer's output and evaluate some plans with the cached results, reducing the number of calls to the optimizer. Still, however, the cost of invoking the optimizer to fill the cache is nontrivial, undermining scalability when running workloads with thousands of queries. In this paper, we use the intermediate optimization results in a dynamic programming based optimizer to reduce the cache initialization overhead. We demonstrate the accuracy and efficiency of our techniques by implementing them on the PostgreSQL open source query optimizer. For a star-schema workload, our techniques build the cost model 5 to 10 times faster than the conventional approach, while preserving accuracy.

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Cerebrospinal fluid (CSF) leakage is considered the cause of spontaneous intracranial hypotension (SIH), an important etiology for new daily persistent headaches and a potentially life-threatening condition. Minor traumatic events rarely lead to CSF leakage, contrasting with iatrogenic interventions such as a lumbar puncture or spinal surgery, which are commonly complicated by dural tears. Most meningeal lesions are found in the cervicothoracic region, followed by the thoracic region, and rarely in the lumbar region, and extremely rarely in the sacral region. We describe two patients admitted to our hospital for severe headaches aggravated in the orthostatic position, with a recent history of minor trauma and sustained physical effort, respectively. In the first case, a bone fragment pierced an incidental congenital meningocele creating a dural fistula. An extensive extradural CSF collection, spanning the cervicothoracic region (C4–T10), was described in the second case. In both patients, the clinical evolution was favorable under conservative treatment.

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One of the most challenging tasks for the database administrator is to physically design the database to attain optimal performance for a given workload. Physical design is hard because it requires the selection of an optimal set of design features from a vast search space. There have been many commercial tools available to automatically suggest the physical design, for a given a set of queries. These tools are, however, based on greedy heuristic pruning, which reduces their usefulness. Furthermore, they are not interactive, as the APIs to simulate the indexes and tables are product specific and hidden from the database administrators. Finally, all these tools are built specifically for commercial systems and there is lack of automated physical designers for open source DBMSs. In this demonstration we introduce -PARINDAan interactive physical designer for an open source DBMS. Given a workload containing a set of queries, this tool allows the DBA to efficiently simulate various physical design features and get immediate feedback on their effectiveness. It also incorporates recent advances in non-greedy physical design techniques to provide close to optimal suggestions. Although it has been prototyped for several different DBMSs, we demonstrate the usefulness and efficiency of the tool while running on the open source DBMS-PostgreSQL--using large real-world scientific datasets and query workloads.