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Traditionally, DBMSs are shipped with hundreds of configuration parameters. Since the database performance highly depends on the appropriate settings of the configuration parameters, DBAs spend a lot of their time and effort to find the best parameter values for tuning the performance of the application of interest. In many cases, they rely on their experience and some rules of thumbs. However, time and effort may be wasted by tuning those parameters which may have no or marginal effects. Moreover, tuning effects also vary depending on the expertise of the DBAs, but skilled DBAs are increasingly becoming rare and expensive to employ. To address these problems, we present a Statistical Approach for Ranking Database parameters (SARD), which is based on the Plackett & Burman statistical design methodology. SARD takes the query workload and the number of configuration parameters as inputs, and using only a linear number of experiments, generates a ranking of database parameters based on their relative impacts on the DBMS performance. Preliminary experimental results using TPC-H and PostgreSQL show that SARD generated ranking can correctly identify critical configuration parameters.

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We present FlashStore, a high throughput persistent key-value store, that uses flash memory as a non-volatile cache between RAM and hard disk. FlashStore is designed to store the working set of key-value pairs on flash and use one flash read per key lookup. As the working set changes over time, space is made for the current working set by destaging recently unused key-value pairs to hard disk and recycling pages in the flash store. FlashStore organizes key-value pairs in a log-structure on flash to exploit faster sequential write performance. It uses an in-memory hash table to index them, with hash collisions resolved by a variant of cuckoo hashing. The in-memory hash table stores compact key signatures instead of full keys so as to strike tradeoffs between RAM usage and false flash read operations. FlashStore can be used as a high throughput persistent key-value storage layer for a broad range of server class applications. We compare FlashStore with BerkeleyDB, an embedded key-value store application, running on hard disk and flash separately, so as to bring out the performance gain of FlashStore in not only using flash as a cache above hard disk but also in its use of flash aware algorithms. We use real-world data traces from two data center applications, namely, Xbox LIVE Primetime online multi-player game and inline storage deduplication, to drive and evaluate the design of FlashStore on traditional and low power server platforms. FlashStore outperforms BerkeleyDB by up to 60x on throughput (ops/sec), up to 50x on energy efficiency (ops/Joule), and up to 85x on cost efficiency (ops/sec/dollar) on the evaluated datasets.