Hi All, I have a strange problem that I think Tomcat is causing it, and I need to confirm if my assumptions are correct.
We have a Tomcat-Standalone (Apache Tomcat/4.0.3) running as a service, we have been working with that version of tomcat for quite sometime with different applications. Most of the applications we used that server for were client server applications that do not perform much data updates (mostly about data pulls and display), and with limited number of concurrent users. However, the recent application that de deployed on the same Tomcat version had a major difference in which there are high frequency of concurrent users and also high rate of data manipulations. The application did not show problems initially, but after couple of months of actual usage, we started noticing strange database discrepancy problems. For example: there are two tables with one to many relationship, the records should be (A1, B1_1), (A1, B1_2) / (A2, B2_1), (A2, B2_2)…etc. For an unknown reason, There are occasional mal-updates that create wrong relationships in the database, so the records might look like (A1, B2_1), (A3, B1_2) We tried to tackle the problem from different perspectives. We performed code inspections, application design inspections, The JDBC Data Bridge used and the database software. The static checks all passed and the semantics appeared ok, it must be some runtime behavior that results in this. I started suspecting Tomcat for the next reason: a bug was reported about an operation that failed to insert in the database. While debugging the database query logs, the reason was that the field type is integer, while the passed value was a "string", we went and inspected the code design and semantics and it was an impossible case that the used "Variable" could have been used in that SQL query. For some reason, at the runtime, a variable reference was switched in the JVM, which suggests a memory leak and a HUGE problem with that version of Tomcat, and that also confirmed to a certain extent the discrepancy problem that occurs with a high volume of user sessions in the recent application. I would appreciate it if someone confirms that suspicion, and whether Tomcat is a reliable server for a high demanding application. Thank you, Andy
