Description: You configure the amount of time a transaction waits before Derby does any deadlock checking with the derby.locks.deadlockTimeout property.
Keywords: deadlocks, configuring detection, configuring lock wait timeouts

# Configuring deadlock detection and lock wait timeouts

You configure the amount of time a transaction waits before Derby does any deadlock checking with the derby.locks.deadlockTimeout property.

You configure the amount of time a transaction waits before timing out with the `derby.locks.waitTimeout` property. When configuring your database or system, you should consider these properties together. For example, in order for any deadlock checking to occur, the `derby.locks.deadlockTimeout` property must be set to a value lower than the `derby.locks.waitTimeout` property. If it is set to a value equal to or higher than the `derby.locks.waitTimeout`, the transaction times out before Derby does any deadlock checking.

By default, derby.locks.waitTimeout is set to 60 seconds. -1 is the equivalent of no wait timeout. This means that transactions never time out, although Derby can choose a transaction as a deadlock victim.

Figure 1. One possible configuration: deadlock checking occurs when a transaction has waited 30 seconds; no lock wait timeouts occur.
Figure 2. Another typical configuration: deadlock checking occurs after a transaction has waited 60 seconds for a lock; after 90 seconds, the transaction times out and is rolled back.
Figure 3. A configuration in which no deadlock checking occurs: transactions time out after they have waited 50 seconds. No deadlock checking occurs.
Parent topic: Deadlocks
Related concepts
Avoiding deadlocks
Deadlock detection
Lock wait timeouts
Debugging Deadlocks
Programming applications to handle deadlocks