Databases Reference
In-Depth Information
5.
The
Active Data Cache
builds and executes SQL queries, and returns the
initial result set
(Snapshot)
to the
Report Cache
.
6.
The
Report Cache
saves the opened
Viewset
and associated Snapshot in
the cache, and then passes the
ViewSet
and
Snapshot
to the
Report Serv-
er
.
7.
The
Report Server
transforms the
Snapshot
to
DHTML
, using View specific
XSL
, and sends it to the client along with
JavaScript
for rendering.
8.
After the initial View is rendered successfully in the web browser, the View
generates a
getChangeList()
request, and sends it through
HTTP POST
to
Report Server ActiveDataServlet
.
Why does the client send a separate HTTP request to
BAM Report Server after a View is rendered for the first
time?
BAM report leverages a push-based mechanism to receive
Active Data in real time. After a report is first rendered in a
web browser, it has to find out a way to register the View
to the Report Server, which maintains persistent connections
between the client and BAM Server. Sending the
getChangeList()
request to
ActiveDataServlet
cre-
ates the persistent connection through which the Active Data
changes are pushed.
Processing Active Data
Up to now, we have mentioned many times that BAM server uses the push-
based mechanism to process Active Data. In this section, we will use a diagram
to illustrate how Active Data are processed by BAM server components:
