Which method is commonly used to visualize application performance issues over time?

Line graphs are commonly used to visualize application performance issues over time because they effectively display trends and changes in data across continuous time intervals. With performance data, it’s crucial to see how metrics evolve, enabling users to identify patterns, spikes, or dips in performance metrics, such as response times or error rates. The line graph's ability to connect data points with a continuous line makes it intuitive for observing fluctuations over time, which is essential in performance monitoring.

Heat maps, on the other hand, are typically used for displaying data intensity across two dimensions but are less effective in showcasing changes over time in a straightforward manner. Pie charts represent parts of a whole, making them unsuitable for time-series data where the focus is on tracking performance trend trajectories. Bar graphs can illustrate performance metrics, but they are generally more effective for comparing discrete categories rather than showing the progression or decline of performance metrics over time.