Oracle and the Cloud - Oracle Essentials - page 360

The one factor that could impact performance in a shared environment like the Database
Cloud is the possibility that one tenant could use too many resources, denying the
resources to others. Some of the lockdown of the Database Cloud, discussed in more
detail below in terms of security, is concerned with preventing this possibility. Any
action that could soak up too many resources is either disallowed or limited, such as
the limit on the number of database jobs each tenant can spawn. Additionally, the Da‐
tabase Cloud uses a series of Database Resource Manager consumer groups to reduce
the priority of any user who exceeds certain thresholds of CPU usage. This approach
means that virtually all requests are complete, but that requests with excessive require‐
ments sacrifice some of their resource availability for the good of the overall Database
Cloud community.
The Database Cloud Service is built on the foundation of Oracle Application Express,
commonly referred to as APEX. The Database Cloud is a relatively new offering, but
APEX has been a part of the Oracle Database technology stack for a while.
History of Application Express
The product known as Application Express began in the late 90s in an Oracle office in
the Washington, DC area. Two sales consultants were interested in the then new envi‐
ronment of the Internet, and HTML, which was the language used to construct pages
retrieved over the Internet. The Oracle database had a feature that allowed generation
of HTML from PL/SQL, so the two intrepid consultants got to work creating a devel‐
opment and deployment environment that could be used to create HTML pages and
serve them up to users from an Oracle database. They also created a listener that would
handle URL requests for these pages.
By 2001, a version of their work, then known as WebDB, was in use inside Oracle for a
variety of applications. The WebDB product underwent a transition, and another ver‐
sion of the same basic tool was created with the name HTML-DB. This product was
more widely adopted, both inside Oracle and by customers, who could use it with the
Oracle Database. The product was renamed Application Express in 2004.
In 2004, Oracle also started the http://apex.oracle.com website. This site gave developers
a sandbox environment to create APEX applications.The site provided a fairly limited
amount of data storage (50 MB), was specifically restricted to development, rather
than production work, and was offered free of charge, as it still is. The http://
apex.oracle.com site was essentially a PaaS platform before anyone had even thought of
the label.
APEX itself has seen fairly wide adoption in the Oracle community. The http://
apex.oracle.com site currently has more than 14,000 individual workspaces. APEX has
been included as a free option for all editions of the Oracle Database since the Database
10 g Release 2, so estimating the worldwide usage of APEX is a bit difficult. However, a
“phonehome” check for updates was implemented in 2012, and in the first half of that