At 05:06 PM 11/28/99 +0530, Sanjay wrote:
>
>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 ?
It seems a bit complex. Why not have a centralized database that
keeps remote databases in sync
with the information that they subscribe to, e.g.,
Cloudscape? Then your servlet is simplified
and security is much improved.
First suggestion: Use a production-quality database. Access is a
toy imo.
>2) Will there be performance degradation ? (Traffic = max 10,000
>users on the Servlet and a max 1000 on each Site)
You want to use MS Access for 1,000 concurrent users??? Don't do it.
>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?
See any good servlet book. www.servletcentral.com (is that still
up?) or www.javaworld.com are
also good sources.
>4) Is there a limit to the number of connections that the Access
>database file can handle at one time ?
Gotta talk to the MS boys about that one.
>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 ?
Use ODBC over dial-up? You do not want to do clear-text ODBC or
JDBC over the wire.
You're using NT... imho, its neither very secure or very crash-proof.
>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.....
See answer to 3.)
>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 ?
unk
>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 ?
You can use serialization, tcp/ip, IIOP... What exactly do you
want to track?
Frank G.
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