[DMDB] Query optimization, basics of memory management

semester4/dmdb/parts/03_systems/01_database-engines/00_memory/00_intro.tex

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+\subsubsection{Storage Management}
+To make database engines easy to use, some abstractions have to happen.
+\begin{figure}[h!]
+    \begin{center}
+        \includegraphics[width=0.7\textwidth]{assets/db-system-memory.png}
+    \end{center}
+    \caption{Overview of a typical abstraction for a database system
+        (Figure from lecture slides 09, slide 3)}
+\end{figure}
+
+In the design of database engines it is commonly assumed that the data is stored on spinning disks, i.e. HDDs, with a high latency for seeks (random accesses)
+and that most of the DB is not in memory.
+
+Very modern database systems may assume that a higher percentage of the DB is stored in memory due to the higher quantity of memory available,
+as well as lower access latencies due to the more readily available SSDs and high-speed NASes.
+
+Some database systems operate similarly to operating systems in certain aspects, in that they manage their own processes and all of the memory
+to get the absolute maximum performance out of the systems.