Measurements are being phased out.They are replaced by span attributes. For measurements sent by legacy SDKs, Relay automatically converts them to span attributes.
Measurements (Legacy)
Measurements are numeric values attached to transactions that capture performance metrics.
mobile
11 measurements| Key | Name | Description | Unit | Attribute |
|---|---|---|---|---|
app_start_cold | App Start Cold | The time it takes for the app to start from a cold state | millisecond | app.vitals.start.cold.value |
app_start_warm | App Start Warm | The time it takes for the app to start from a warm state | millisecond | app.vitals.start.warm.value |
frames_frozen | Frozen Frames | The number of frames that took longer than 700ms to render | — | app.vitals.frames.frozen.count |
frames_frozen_rate | The rate of frozen frames | measurements.frames_frozen divided by the measurements.frames_total | — | app.vitals.frames.frozen.rate |
frames_slow | Slow Frames | The number of frames that took longer than 16ms (Android) or 16.67 (iOS) to render | — | app.vitals.frames.slow.count |
frames_slow_rate | The rate of slow frames | measurements.frames_slow divided by the measurements.frames_total | — | app.vitals.frames.slow.rate |
frames_total | Total Frames | Total frames rendered. | — | app.vitals.frames.total.count |
stall_count | Stall Count | A stall is when the JavaScript event loop takes longer than expected to complete. Only applies to React Native | — | — |
stall_longest_time | Longest Stall Time | The longest stall time is the time of the longest event loop stall. Only applies to React Native. | milliseconds | — |
stall_percentage | Stall Percentage | Stall percentage is equal to app.vitals.stall.duration divided by transaction.duration. Only applies to React Native. | — | app.vitals.stall.percentage |
stall_total_time | Total Stall Time | The total stall time is the total combined time of all stalls. Only applies to React Native. | milliseconds | app.vitals.stall.duration |
web
8 measurements| Key | Name | Description | Unit | Attribute |
|---|---|---|---|---|
cls | Cumulative Layout Shift | Tthe sum total of all individual layout shift scores for every unexpected layout shift that occurs during the entire lifespan of the page | — | browser.web_vital.cls.value |
fcp | First Contentful Paint | The time it takes for the browser to render the first piece of meaningful content on the screen | millisecond | browser.web_vital.fcp.value |
fid | First Input Delay | The time from when a user first interacts with a page to the time when the browser is actually able to begin processing event handlers in response to that interaction | millisecond | — |
fp | First Paint | The time it takes for the browser to render the first pixel on the screen | millisecond | browser.web_vital.fp.value |
inp | Interaction to Next Paint | The time it takes for the browser to render the next frame after a user interacts with the page. | millisecond | browser.web_vital.inp.value |
lcp | Largest Contentful Paint | The time it takes for the largest contentful paint element to be rendered on the screen | millisecond | browser.web_vital.lcp.value |
ttfb | Time to First Byte | The time it takes for the first byte of a response from the server to reach the user's browser after a request is made | millisecond | browser.web_vital.ttfb.value |
ttfb.requesttime | Time to First Byte (Request Time) | The time it takes for the server to process the initial request and send the first byte of a response to the user's browser | millisecond | browser.web_vital.ttfb.request_time |