![]() ![]() The wait for the graph is maintained by the system for every transaction which is waiting for some data held by the others.If the created graph has a cycle or closed loop, then there is a deadlock. In this method, a graph is created based on the transaction and their lock. This is the suitable method for deadlock detection.The lock manager maintains a Wait for the graph to detect the deadlock cycle in the database. In a database, when a transaction waits indefinitely to obtain a lock, then the DBMS should detect whether the transaction is involved in a deadlock or not. For the larger database, deadlock prevention method can be used. A method like "wait for graph" is used for detecting the deadlock situation but this method is suitable only for the smaller database. Deadlock avoidance mechanism is used to detect any deadlock situation in advance.When a database is stuck in a deadlock state, then it is better to avoid the database rather than aborting or restating the database.It will remain in a standstill until the DBMS detects the deadlock and aborts one of the transactions. All activities come to a halt state and remain at a standstill. Now Transaction T1 is waiting for T2 to release its lock and similarly, transaction T2 is waiting for T1 to release its lock. Simultaneously, transaction T2 holds locks on some rows in the grade table and needs to update the rows in the Student table held by Transaction T1. Deadlock is said to be one of the most feared complications in DBMS as no task ever gets finished and is in waiting state forever.įor example: In the student table, transaction T1 holds a lock on some rows and needs to update some rows in the grade table. ![]() ![]() A deadlock is a condition where two or more transactions are waiting indefinitely for one another to give up locks. ![]()
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