[jboss-jira] [JBoss JIRA] Closed: (JBAS-3679) BMP entitybeans cause db-deadlocks

BMP entitybeans cause db-deadlocks ---------------------------------- Key: JBAS-3679 URL: http://jira.jboss.com/jira/browse/JBAS-3679 Project: JBoss Application Server Issue Type: Bug Security Level: Public(Everyone can see) Components: Transaction Manager Affects Versions: JBossAS-3.2.7 Final Environment: windows 2003, sun jvm 1.4.2_06, INet Opta JDBC driver 6.04, SQLSERVER 2000 Reporter: Onno de Groote when using local-tx datasources with no transactionisolation-level specified, it looks like jboss sets it to repeatable-read or higher. The problem with this situation is that in high concurrency situations, two threads using the same entity-bean ( with or without same primary-key ) cause deadlocks in SQLServer. The reason for this is that de select queries in the findby and ejbload code set S-locks on the indexes in the database, thereby blocking any update query of a different thread. In the situation that thread-1 first performs the findby and ejbload, causing S-locks, after which thread-2 does the same, after which thread-1 tries ejbstore, which blocks because of the S-locks of thread-2. Then thread-2 tries the ejbstore, which in turn is blocked by the S-locks of thread-1. SQLServer detectes a deadlock and selects a deadlock victim and one transaction fails. In this case there should not have been a problem so the transaction-failure is incorrect and only caused by the wrong transactionisolation level