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From "Tom Drake" <>
Subject Re: Multi-user problem
Date Wed, 06 Feb 2002 23:54:16 GMT
See my comments below.

----- Original Message -----
From: <>
To: <>
Sent: Wednesday, February 06, 2002 3:23 PM
Subject: Multi-user problem

... snip ...
| Apache 1.3 is a service on Windows 2000 running Tomcat 4 on the same
server, with SQL server 2000 SP1 on the same server.
| My system has 2 servlets, AUDREPORT and NEXTIMAGE.  AUDREPORT is run once
per user at login.
| NEXTIMAGE is called repeatedly (say 1000 to 3000 times per workshift per
| Database connections are made through ODBC with the JDBC:ODBC:DSN bridge
using the sun.jdbc.odbc.JdbcOdbcDriver driver.  I used a SYSTEM DSN.

The JDBC/ODBC bridge is notoriously bad and not thread safe.
This could be the root of your problems. If you are using
MS-ACCESS, I think you're probably stuck with it and will
have to synchronize around your database calls. I'm pretty
sure there is a 'real' JDBC driver available for SQL Server.

... snip ...
| The NEXTIMAGE servlet looks something like this pseudo-code:
| public static void login(...){ Tell database user is logged in. }
| public static void logout(...) {Tell database user is logged out.}
| public static void updateaccesstime(...) {Tell Database I made a request}

Are the above functions keeping class data
(such as a connection to your database)?

If a 'login' request gets a new database connection,
then any other thread that is using
the original connection will break.

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