Why is it important to allow concurrent transactions?
So, allowing concurrent transactions is essential from the performance point of view but allowing concurrent transactions may also introduce some concurrency issues when two or more transactions are working with the same data at the same time.
What do you call the process of concurrent execution?
This process is called a concurrent execution. Decrease waiting time or turnaround time. Increased throughput or resource utilization. Several problems can occur when concurrent transactions are run in an uncontrolled manner, such type of problems is known as concurrency problems.
How to recover from a failed concurrent transaction?
Recovery with concurrent transactions can be done in the following four ways. In this scheme, the recovery scheme depends greatly on the concurrency control scheme that is used. So, to rollback a failed transaction, we must undo the updates performed by the transaction.
What is a fuzzy checkpoint in concurrent transaction processing?
In a concurrent transaction processing system, we require that the checkpoint log record be of the form , where ‘L’ is a list of transactions active at the time of the checkpoint. A fuzzy checkpoint is a checkpoint where transactions are allowed to perform updates even while buffer blocks are being written out.
What do you need to know about concurrency?
When we talk about transactions, one more thing which we need to handle is concurrency. Concurrency is nothing but it is a situation where two users are trying to access the same information and while they are accessing the same information we do not want any kind of inconsistency result or abnormal behavior.
How to deal with concurrency problems in SQL Server?
To overcome the above two problems, SQL Server provides different types of transaction isolation levels, to balance the concurrency problems and performance depending on our application’s need. The Transaction Isolation Levels provided by SQL Server are as follows
What does complete isolation of concurrently running transactions mean?
Complete isolation of concurrently running transactions could mean that one transaction cannot perform an insert into a table being queried by another transaction. In short, real-world considerations usually require a compromise between perfect transaction isolation and performance.