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A schedule is said to be conflict-serializable when the schedule is conflict-equivalent to one or more serial schedules. Equivalently, a schedule is conflict-serializable if and only if its precedence graph is acyclic when only committed transactions are considered. Note that if the graph is defined to also include uncommitted transactions ...
The scheduler is an operating system module that selects the next jobs to be admitted into the system and the next process to run. Operating systems may feature up to three distinct scheduler types: a long-term scheduler (also known as an admission scheduler or high-level scheduler), a mid-term or medium-term scheduler, and a short-term scheduler.
Commit/Rollback: If there is no conflict, make all changes take effect. If there is a conflict, resolve it, typically by aborting the transaction, although other resolution schemes are possible. Care must be taken to avoid a time-of-check to time-of-use bug, particularly if this phase and the previous one are not performed as a single atomic ...
This could be produced by a TO scheduler, but is not recoverable, as commits even though having read from an uncommitted transaction. To make sure that it produces recoverable histories, a scheduler can keep a list of other transactions each transaction has read from , and not let a transaction commit before this list consisted of only ...
Priority inheritance algorithms can be characterized by two parameters. First, is the inheritance lazy (only when essential) or immediate (boost priority before there is a conflict). Second is the inheritance optimistic (boost a minimum amount) or pessimistic (boost by more than the minimum amount):
In computer science, resource contention is a conflict over access to a shared resource such as random access memory, disk storage, cache memory, internal buses or external network devices. A resource experiencing ongoing contention can be described as oversubscribed .
The cron command-line utility is a job scheduler on Unix-like operating systems.Users who set up and maintain software environments use cron to schedule jobs [1] (commands or shell scripts), also known as cron jobs, [2] [3] to run periodically at fixed times, dates, or intervals. [4]
Windows NT processor scheduling refers to the process by which Windows NT determines which job (task) should be run on the computer processor at which time. Without scheduling, the processor would give attention to jobs based on when they arrived in the queue, which is usually not optimal.