Hi,
[Couldn't see any attached diagram.]
Some answers :
2) See Jason Hunter's book "Java Servlet Programming" by O'Reilly,
for a sample Connection pool handler and pointers to others.
4) Not too sure how good MS Access is for this kind of scenario.
Might be better to use SQL Server or some other robust RDBMS,
if you can. If cost is the reason for using Access you could try out some
of the other low-end versions of enterprise databases, such as Oracle Lite/
SQL Anywhere or Borland's (now Inprise) Interbase (very small footprint,
has good JDBC support). Whichever DB you choose, write a simple Java/JDBC
test program to find out the number of connections supported.
Call DriverManager.getConnection() in a loop (say 1 to 1000) and assign each
returned Connection to an element of a Vector, printing out the loop index
at
the same time. [You could also use the DatabaseMetaData.getMaxConnections()
method, but I don't know if the result is reliable - it returned 0 for
Informix
with Informix JDBC driver.] Best is to write the test program and then run
it
till it fails. The last index printed will give you an idea of the number
of
simultaneous connections supported by your DB.
6) See answer 2).
7) Check the Netscape web site for technical support.
8) See answer 2).
Suggest you get the Servlet API docs, Jason's book & read both thoroughly,
if you haven't already. Jason's book particularly is damn good. I am telling
you this because I am reading it now for the second time and learning
a lot more from it. It's a gold mine.
There's no substitute for reading - people will answer questions here but
unless you do the background work you won't get the full benefit of the
their answers.
Another general tip - wherever possible, write small test programs - both
to find out something, as in the no. of connections above, and to
clarify/verify
your understanding of how things work.
HTH
Vasudev
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Vasudev Ram
Infosys Technologies Limited
Pune, India
Email : [EMAIL PROTECTED]
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
On a clear day you can see the blue screen of death.
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Hi all,
I'm designing a Servlet based data-access utility. The architecture
of the setup is diagrammatically shown in the attached file. There are about
10 different sites at which data is stored, in MS-access mdb files.
The Servlet will validate the users against these databases. Further
transactions will also use the same database. Each site is connected to the
Web server using dial-up connection. There are two m/c at each site, a RAS
m/c and a winNT m/c on which the mdb file exists.
The Servlet takes queries from users and creates an instance of a
TCP/IP client (for each user). This sends the request data to the
corresponding TCP/IP server over socket. The server (multithreaded) then
passes on this request to the Database access module, which accesses/updates
data from the mdb file thru JDBC-ODBC bridge. The client socket accepts
data/error msg from the server socket and returns it to the Servlet. Servlet
then sends the result to the user's browser. A normal transaction for a user
involved 4-5 of such cycles. (i.e.: session tracking has to be done) . The
platform is WinNT for all the machines.
I would like to know the following things :
1) Is the architecture correct ?
2) Will there be performance degradation ? (Traffic = max 10,000 users
on the Servlet and a max 1000 on each Site)
3) How do I implement connection pooling at each site ? (Particularly,
how do i maintain the number of connections, to be just enough for the
request traffic?). Can someone gimme code snippet for this please?
4) Is there a limit to the number of connections that the Access
database file can handle at one time ?
5) Is it feasible to drop the client/server modules and directly
access the mdb files from the Servlet ? (thru ODBC configured on the Web
server) If it is, how secure and crash-proof is the ODBC connection over
dial-up ?
6) I plan to use Applet-servlet communication. Can anyone please gimme
a few pointers on this ? and maybe some code snippet to start on.....
7) I tried to configure Netscape Enterprise Server v3.6 SP2 (on WinNT
SP5) but it fails to start the Web Server and Admin Server services. It
gives Windows Internal Error when i try to manually start the service. Can
anybody help me out here ?
8) Since Session tracking API are not supported by this web server, how
do I perform session tracking ? Can I use the applet for sending state info
to the server ? How to implement it ?
The list is long and many questions are off-topic. But being inexperianced i
felt i should ask my doubts to all the Gurus out there........PLEASE help me
out guys........i would be thankful for ANY help on ANY part of the
above.....
Lots of thanks in advance,
Sanjay Karanjkar
Systems Engineer
Tata Infotech Ltd.
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