Basic Oracle Concepts and Programming Question:
What Is a Dead Lock in Oracle?
Answer:
A dead lock is phenomenon happens between two transactions with each of them holding a lock that blocks the other transaction as shown in the following diagram:
<pre>(transaction 1) (transaction 2)
update row X to create lock 1
update row Y to create lock 2
update row X
(blocked by lock 1)
update row Y</pre>
(blocked by lock 2)
(dead lock created)
<pre>(transaction 1) (transaction 2)
update row X to create lock 1
update row Y to create lock 2
update row X
(blocked by lock 1)
update row Y</pre>
(blocked by lock 2)
(dead lock created)
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