Concurrency
Concurrency is the ability of multiple tasks, processes, or threads to execute during overlapping periods of time within a system.
“The simultaneous execution of multiple independent threads by a component or system.”
(Definition reproduced from the ISTQB Glossary. Copyright belongs to ISTQB.)
View the complete ISTQB GlossaryWhat is Concurrency?
Concurrent execution improves performance and responsiveness but introduces challenges such as synchronization, resource sharing, and race conditions.
Parallel activities: Multiple operations may occur simultaneously or appear simultaneous.
Shared resources: Concurrent tasks often compete for common resources.
Testing importance: Concurrency issues may appear only under realistic workloads.
Real World Example
A regulated product team is preparing a release where Concurrency appears in reviews, test design conversations, or defect triage rather than as an isolated glossary word.
The risk is that the team treats Concurrency as interchangeable with nearby ISTQB terms. That makes test scope blurry and can lead to weak evidence for the release decision.
The tester anchors the discussion in the official definition, asks where the concept appears in the product, and designs examples that show the difference between Concurrency and similar ideas.
The page becomes useful in practice because Concurrency is connected to a specific testing decision, not memorized as a detached definition.
Practice Questions
Question 1
Which symptom MOST indicates a race condition?
Question 2
Which technique helps expose concurrency bugs?
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