JDBC type-2 SQL connection supporting multiple concurent threads?

From: <scottdwyer_at_my-deja.com>
Date: Thu, 16 Sep 1999 18:56:29 GMT
Message-ID: <7rregm$pe8$1@nnrp1.deja.com>

Environment:
Server A

DominoGo Webserver version 4.6.1
IBM Websphere Application Server 1.1 (or 2.02) - we have several servers with different versions of Websphere
Oracle 7.3.2 (I think !)
application code (Java servlets)

Server B

Oracle 7.3.2 (I think !)
DominoGo Webserver version 4.6.1 (not relevant for this scenario)
IBM Websphere Application Server 1.1 (or 2.02) - not relevant for this scenario

Description:
From Server Aour application code (Java servlets) use the IBM Connection Manager (from Websphere) to manage a pool of connections to the database on Server B . So, our servlets get an IBM Connection (which is a wrapper for an SQL connection) from the pool, then get the corresponding SQL connection from the IBM Connection, and then they do straight SQL to the database on Server B . The servlets create threads which take the connection that the servlet had and use it to get real data from the database. In some instances we probably have around 20-30 threads spawned by a servlet per user. All threads use the same connection they got from the servlet which is run by a user. This seems to be working pretty good for one or two users, however, once we get 5 users or above hitting the application at the same time, we get a hang. Sometimes, everybody hangs, once somebody actually got through and the others didn't, etc. This is using a type 2 JDBC driver. We tried a type-4 but that gave us some deadlocks, invalid SQL exceptions (invalid column name, etc), incomplete data in some instances (that's with 7 concurent users - again, with only one or two users, everything appears normal). With type-2, it looks like the Oracle SQL connection does pretty good with serialization so we don't use synchronized methods in Java.

Question:
Do we have a problem if 50 threads try to use the same JDBC type-2 SQL connection at the same time ? Any answer will be greatly appreciated.

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Share what you know. Learn what you don't. Received on Thu Sep 16 1999 - 13:56:29 CDT