Hossain_BM.pdf (1.95 MB)
Download fileEnhancing Parallelism and Scalability of Database-Centric Applications in Presence of Database Deadlocks
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posted on 20.06.2014, 00:00 authored by BM M. HossainCurrently, in Database-Centric Applications (DCAs), database deadlocks are typically detected at runtime within database engines using special algorithms that analyze whether resources are held in cyclic
dependencies, and these database engines resolve database deadlocks by
forcibly breaking the hold-and-wait cycle. That is, once a deadlock
occurs, the database rolls back one of the SQL statements that is
involved in the circular wait. This resolution causes severe performance
degradation, since DCAs should repeat the rolled back SQL statements to
ensure functional correctness. Doing so not only reduces parallelism in
executing SQL statements by databases, but also requires these databases to re-execute the same SQL statements thus decreasing the throughput and negatively affecting the scalability of the DCAs.
We present novel solutions to a fundamental problem of predicting and
preventing database deadlocks (PD)2 in DCAs, and we rigorously evaluate
these solutions on several different open-source and commercial DCAs,
some of which still exhibit database deadlocks after having been used
for close to two decades. In evaluating (PD)2, we addressed various research questions that establish the effectiveness of our solutions.