Describe the life cycle of a transaction.

The Two-Phase Commit (2PC) protocol is used in distributed transaction systems to ensure all participants in a transaction agree on whether to commit or abort the transaction. Its role includes:

1. **Commit Coordination:** Ensures that all involved nodes or systems in a distributed transaction either commit the transaction or rollback to maintain consistency across the entire system.

2. **First Phase (Prepare):** The coordinator sends a prepare request to all participants. Each participant responds with a vote to either commit or abort, based on their ability to complete the transaction.

3. **Second Phase (Commit/Abort):** If all participants vote to commit, the coordinator sends a commit message, and all participants finalize the transaction. If any participant votes to abort, the coordinator sends an abort message, and all participants rollback the transaction.

4. **Consistency:** Guarantees that the transaction is atomic and consistent across all nodes, even in the case of failures or crashes.

The 2PC protocol is crucial for maintaining data integrity and consistency in distributed systems where multiple databases or nodes are involved in a single transaction.