What is a Distributed Transaction?

A distributed transaction is defined as a group of operations that are to be performed across more than one database or data repository. The operations are performed by multiple nodes that are connected to a single network. The distributed transaction ensures ACID (Atomicity, Consistency, Isolation, Durability) properties and data integrity.

What is the Need For Distributed Transaction?

Some properties are harder to implement, that cannot be implemented with simple transactions. Many times basic single-system techniques are not sufficient. Distributed transactions are required when there is a need to quickly update data that is related and spread across the multiple databases or nodes connected in a network.

Working of Distributed Transactions

The working of Distributed Transactions is the same as that of simple transactions but the challenge is to implement them upon multiple databases. Due to the use of multiple nodes or database systems, there arises certain problems such as network failure, to maintain the availability of extra hardware servers and database servers. For a successful distributed transaction the available resources are coordinated by transaction managers.

Working of Distributed Transactions

Step 1: Application to Resource – Issues Distributed Transaction

The first step is to issue that distributed transaction. The application initiates the transaction by sending the request to the available resources. The request consists of details such as operations that are to be performed by each resource in the given transaction.

Step 2: Resource 1 to Resource 2 – Ask Resource 2 to Prepare to Commit

Once the resource receives the transaction request, resource 1 contacts resource 2 and asks resource 2 to prepare the commit. This step makes sure that both the available resources are able to perform the dedicated tasks and successfully complete the given transaction.

Step 3: Resource 2 to Resource 1 – Resource 2 Acknowledges Preparation

After the second step, Resource 2 receives the request from Resource 1, it prepares for the commit. Resource 2 makes a response to resource 1 with an acknowledgment and confirms that it is ready to go ahead with the allocated transaction.

Step 4: Resource 1 to Resource 2 – Ask Resource 2 to Commit

Once Resource 1 receives an acknowledgment from Resource 2, it sends a request to Resource 2 and provides an instruction to commit the transaction. This step makes sure that Resource 1 has completed its task in the given transaction and now it is ready for Resource 2 to finalize the operation.

Step 5: Resource 2 to Resource 1 – Resource 2 Acknowledges Commit

When Resource 2 receives the commit request from Resource 1, it provides Resource 1 with a response and makes an acknowledgment that it has successfully committed the transaction it was assigned to. This step ensures that Resource 2 has completed its task from the operation and makes sure that both the resources have synchronized their states.

Step 6: Resource 1 to Application – Receives Transaction Acknowledgement

Once Resource 1 receives an acknowledgment from Resource 2, Resource 1 then sends an acknowledgment of the transaction back to the application. This acknowledgment confirms that the transaction that was carried out among multiple resources has been completed successfully.

Advantages of Distributed Transactions

• Data Consistency: Data Consistency is being provided across multiple resources by distributed transactions. Various Operations are being coordinated across multiple database resources. This makes sure that system remains in a consistent state even in case of any type of failure.
• Fault Tolerance: Distributed systems can handle faults and ensure proper transactions. If the participating resource fails during the execution of the transaction the transaction can be then rolled back on alternate resources and completed successfully.
• Guarantees Transactions: Distributed systems guarantee the transaction. It provides features such as durability and isolation. The durability makes sure that if any transaction is committed, the changes last even if any failures occur.

Applications Area of Distributed Transactions

• Enterprise Resource Planning (ERP) Systems: ERP systems consist of departments within one organization. Therefore distributed transactions are used here in order to maintain transactions from various modules such as sales, inventory, finance, and human resources management.
• Cloud Computing: Distributed transactions are being used in cloud-based applications. Transactions can be done with the help of multiple data sources and ensure that data updates and operations that are performed consistently.
• Healthcare Systems: Healthcare systems make use of Distributed transactions when coordinating patient records, scheduling appointments for patients, and managing the billing systems. Distributed transactions maintain data consistency and performance in healthcare systems.

Conclusion

Distributed transactions are used when multiple resources such as repositories or database systems are used in order to perform the transaction. Distributed transactions provide various benefits such as data consistency, guarantees transaction, and improve the overall performance and scalability of the system. Therefore distributed transactions are being used in various applications in order to gain the above benefits.

FAQs on Distributed Transaction

Q.1: Explain why distributed transactions are necessary in distributed transactions?

Answer:

Distributed transactions are needed in order to maintain the integrity and consistency of data access the multiple data resources such as repositories or databases connected in a same network. Distributed transactions coordinates the operations across multiple resources.

Q.2: What happens if any participating resource fails during a distributed transaction?

Answer:

If any participating resource fails during the transaction, the coordinator of transaction detects this failure and then initiates proper recovery mechanisms. Mechanisms it can involve includes resending the transaction to some other alternative available, abortion of transaction, and retrying the operation on same failed resource.

Q.3: What are the goals of distributed transactions?

Answer:

The main aim of Distributed Transactions is to maintain the durability, atomicity, isolation and fault tolerance.

Q.4: What is the role of the transaction coordinator in distributed transactions?

Answer:

The transaction coordinator in distributed systems is responsible for initiating and then coordinating the transaction for its succesful completion. It makes sure that all the resources involved in the transaction are working.