The purpose of transaction sequencing is to ensure that as many transactions as possible are completed on time. There are many different transaction prioritization policies in place. Some of these will be covered in the current workflow. Each transaction in real time has meaning, that is, the value of executing that transaction at a given time.Each transaction also has a deadline - a deadline after which the execution of the transaction makes no sense. The queue creation algorithm is to assign priorities to transactions. For transactions, there are time value dependencies, relative to the deadline. They can be different, but below are the main simple functions of the Hard Deadline: not executing a transaction in time can lead to a catastrophe Soft Deadline: it makes sense to execute even if the deadline is missed Hard Deadline: when the deadline expires, executing the transaction makes no sense, but also no loss. Controlling parallel execution There are many ways to classify schedulers. One obvious way is to classify by type of database distribution. Some schedulers require full replay of the database, while others can work with partially replayed or database load testing using jmeter split databases.
Schedulers can also be classified according to network topology. However, the most common classification is based on basic synchronization methods, i.e. methods that provide data access and allow ordering transactions according to a set of rules. There are two points of view: pessimistic, which implies that a large number of transactions will conflict with each other, and optimistic, which implies the opposite. Pessimistic methods synchronize the simultaneous on premise database execution of transactions at the beginning of their execution, while optimistic methods delay the synchronization of transactions until their completion. The field of database development has made a huge progress in a relatively short time of its existence. Today, many technology areas in the world are moving to more modern systems with a large amount of input data and a high flow of information, where real-time databases are needed. The information provided in this article will be useful for designing and operating real-time databases.