Compacting Transactional Data in Hybrid OLTP & OLAP Databases [article]

Florian Funke, Alfons Kemper, Thomas Neumann
<span title="2012-08-01">2012</span> <i > arXiv </i> &nbsp; <span class="release-stage" >pre-print</span>
Growing main memory sizes have facilitated database management systems that keep the entire database in main memory. The drastic performance improvements that came along with these in-memory systems have made it possible to reunite the two areas of online transaction processing (OLTP) and online analytical processing (OLAP): An emerging class of hybrid OLTP and OLAP database systems allows to process analytical queries directly on the transactional data. By offering arbitrarily current
more &raquo; ... of the transactional data for OLAP, these systems enable real-time business intelligence. Despite memory sizes of several Terabytes in a single commodity server, RAM is still a precious resource: Since free memory can be used for intermediate results in query processing, the amount of memory determines query performance to a large extent. Consequently, we propose the compaction of memory-resident databases. Compaction consists of two tasks: First, separating the mutable working set from the immutable "frozen" data. Second, compressing the immutable data and optimizing it for efficient, memory-consumption-friendly snapshotting. Our approach reorganizes and compresses transactional data online and yet hardly affects the mission-critical OLTP throughput. This is achieved by unburdening the OLTP threads from all additional processing and performing these tasks asynchronously.
<span class="external-identifiers"> <a target="_blank" rel="external noopener" href="">arXiv:1208.0224v1</a> <a target="_blank" rel="external noopener" href="">fatcat:yffj7szidjbt3euylqm7unagjq</a> </span>
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