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Physical Sciences and Mathematics Commons

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Theses/Dissertations

1998

Databases and Information Systems

Theses : Honours

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Full-Text Articles in Physical Sciences and Mathematics

An Experimental Study Into The Effect Of Varying The Join Selectivity Factor On The Performance Of Join Methods In Relational Databases, Ada Mallet Jan 1998

An Experimental Study Into The Effect Of Varying The Join Selectivity Factor On The Performance Of Join Methods In Relational Databases, Ada Mallet

Theses : Honours

Relational database systems use join queries to retrieve data from two relations. Several join methods can be used to execute these queries. This study investigated the effect of varying join selectivity factors on the performance of the join methods. Experiments using the ORACLE environment were set up to measure the performance of three join methods: nested loop join, sort merge join and hash join. The performance was measured in terms of total elapsed time, CPU time and the number of I/O reads. The study found that the hash join performs better than the nested loop and the sort merge under …