Database Reference
In-Depth Information
Figure1-1.CAP Theorem indicates that you can realize only two of these properties at once
It might prove useful at this point to see a graphical depiction of where each of the nonrelational
data stores we'll look at falls within the CAP spectrum. The graphic in
Figure 1-2
was inspired
by a slide in a 2009 talk given by Dwight Merriman, CEO and founder of MongoDB, to
the MySQL User Group in New York City (you can watch it online at
http://bit.ly/7r6kRg
).
However, I have modified the placement of some systems based on my research.
Figure 1-2
shows the general focus of some of the different databases we discuss in this chapter.
Note that placement of the databases in this chart could change based on configuration. As
Stu Hood points out, a distributed MySQL database can count as a consistent system only if
you're using Google's synchronous replication patches; otherwise, it can only be Available and
Partition-Tolerant (AP).
It's interesting to note that the design of the system around CAP placement is independent of
the orientation of the data storage mechanism; for example, the CP edge is populated by graph
databases and document-oriented databases alike.
