A: Queries in the STREAM system are expressed in the CQL
(Continuous Query Language) declarative query language for data
stream systems. A quick introduction to CQL is available
here. This page also contains more
references on CQL.
Q: When I attempt to register a CQL query, I get a parse error or
a semantic error. Where can I find the CQL syntax and semantics
specification?
A: The authoritative source on CQL query syntax
supported currently by STREAM is available
here.
Q: How do I interpret the query results?
A: Results are reported back
in a scrollable tabular format with the
result tuples displayed in increasing timestamp order
from bottom to top of the results window. That
is, more recent tuples are displayed on top. The results window
is configured to display the 10,000 most recent updates
to the query result. Once the number of result updates
so far exceeds 10,000, the oldest ones are dropped from
the bottom of the scrollable results window.
Q: When I start the demo, I get some popup related to Desktop Integration
and then the entire demo freezes?
A: We think this problem occurs on some Windows XP machine, and we do
not understand Desktop Integration mechanics on Windows XP well enough
to fix this cleanly. The following sequence seems to work around this
problem: When you get the popup click on the "Configure"
button and select the "Never Integrate" option, and start
the demo all over again.