Information Technology Reference
In-Depth Information
search (over 40% of the entire database). It was observed that when the
number of resultant accident records was too high for a region (e.g., greater
than 6,000), then on some occasions the application crashed and showed the
error request time-out. After some research, it was realized that this was
happening because of the default keep-alive time of the WCF-RIA service.
For a WCF-RIA service request, the default keep-alive time on the client
machine is 1 minute, and if a query response from the SQL server takes
more than a minute, then the WCF-RIA service causes this error because
the client side assumes that the connection with the domain service on the
web server is broken.
After resolving this issue, this stress test has been performed repeatedly
but from 10 different client machines at the same time. Although the response
time was slow (up to 5 minutes), the overall architecture has worked, proving
that the system is stable under stress conditions. For a small date range and
with some conditions, the search is typically nimble, with response time
within a couple of seconds.
Hence, our demo has worked in its most basic form, but there is a lot of room
for improvement using the cloud computing capabilities. As an example,
if a user requires extensive access to historical data (e.g., all the accidents that
happened in the last 20 years), the result will be a region cluttered with thou-
sands of accident location pins showing the problematic areas, which may be
slightly difficult to read on a low-resolution screen.
7.5.2 Processing Time
A key performance parameter is how much time it takes to display a
response/result on the client machine after sending a search request. This is
dependent on the size of the accident search results, the client's Internet speed,
processing required by the map objects parser, and processing required on
SQL Azure. To analyze the processing time, a search is performed that returns
records of all the accidents in a given postcode area (AB) in the database. This
search actually executes a query in SQL Azure as shown in Listing 7.1.
L ist i ng 7.1
SQL query in Azure
SELECT
[RID] [AccID] [AccDate] [AccTime] [Cause] [Longitude]
[Latitude] [AccInjuredPersons] [AccVehicles]
FROM
[AccidentManagement][dbo][viewPolyAccidents]
WHERE
RegionID = AB
To check how much time SQL Azure takes to execute this query, the query
has been executed 10 times via the SQL Server Management Studio. The aver-
age execution time was 76 seconds. When a similar search was performed
Search WWH ::
Custom Search