Consider the following problem: We have a web app which can send messages between the users that are connected to it. A user can send a message to any number of users. The implementation is simple: When a user sends a message: The message is saved in the database Cache value is inserted for each recipient. The saved value is a time stamp which indicates when the user last received a message. Users that are suppose to see the message: The client is polling the server and asks if the server has new...
In one bright day, our integration tests in the build server started to fail randomly. Each test that failed showed this message: ORA-02049: timeout: distributed transaction waiting for lock These were integration tests on our database (Oracle database). Each of these tests had opened a distributed transaction and rolled it back to prevent changes in the database (Using the System.Transactions.TransactionScope). Each time we ran them, different tests had failed. The strangest thing was that newer...