ACID Problems in a Multithreaded Environment?

The JDBC classes are not reentrant, so you have to synchronise use of object instances of connection, statement, etc. They cannot savely be used by multiple threads concurrently. Use of a connection pool is a good way to streamline concurrent access to a database. Edit If you're sure that the threads never use the same connection, you could check can the pool be out of connections?

How is that handled? Could it be that 2 updates act on the same record where the first get overwritten? Do you catch all exceptions and log them in your workers?

The sad thing is, that I am already using a Connection Pool (BoneCP) ... I also use a ThreadPoolExecutor to handle the different Threads that execute the SQL operations - the workqueue used for the ThreadPoolExecutor works in a FIFO way. I thought that these both technologies would ensure an errorless concurrent access to a database. – Vilius Nov 12 at 19:36 @Villius, see edit – rsp Nov 12 at 19:45 Thank's for the suggestions!

I basically think that the second bullet point causes the problems ... That is why I believe that the error occurs at the MySQL Server rather than at the Java Connection Pool/ ThreadExecutor. I also heared that MySQL 5.5 has better support for InnoDB locking? Is it true?(I'm still using 5.1.X) – Vilius Nov 12 at 19:49.

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