Performance Monitoring uses
traces
to collect data about monitored processes in your app.
A trace is a report that contains data captured between two points in time
in your app.
For Apple and Android apps, Performance Monitoring
automatically
collects several traces
related to app lifecycle. All these traces are like timers because they measure
the time it takes for the process to run (the "duration").
App start trace
? A trace that measures the time between when
the user opens the app and when the app is responsive
App-in-foreground trace
? A trace that measures the
time when the app is running in the foreground and available to the user
App-in-background trace
? A trace that measures the
time when the app is running in the background
Since these traces only collect the metric "duration", they are sometimes called
"Duration traces".
You can view data from these traces in the
Custom traces
subtab of the traces
table, which is at the bottom of the
Performance
dashboard (learn more about
using the console
later on this page).
Definitions for each trace
Performance Monitoring uses method calls and notifications in your app to determine when
each type of trace starts and stops. All these traces are like timers because
they measure the time it takes for the process to run.
App start trace
This trace measures the time between when the user opens the app and when the
app is responsive. In the console, the trace's name is
_app_start
. The
collected metric for this trace is "duration".
Starts when the application loads the first
Object
to memory.
Stops after the first successful run loop that occurs after the application
receives the
UIApplicationDidBecomeActiveNotification
notification.
App-in-foreground trace
This trace measures the time when the app is running in the foreground and
available to the user. In the console, the trace's name is
_app_in_foreground
.
The collected metric for this trace is "duration".
App-in-background trace
This trace measures the time when the app is running in the background. In the
console, the trace's name is
_app_in_background
. The reported metric for this
trace is "duration".
Metrics collected by these traces
These traces are out-of-the-box traces, so you cannot add custom metrics or
custom attributes to them.
All these traces are like timers because they measure the time it takes for the
monitored process to run. The name of this collected metric is called
"duration".
Track, view, and filter performance data
To view real-time performance data, make sure that your app uses a Performance
Monitoring SDK version that's compatible with real-time data processing.
Learn more about real-time performance data
.
Track key metrics in your dashboard
To learn how your key metrics are trending, add them to your metrics board at the top of the
Performance
dashboard. You can quickly identify regressions by seeing week-over-week
changes or verify that recent changes in your code are improving performance.
To add a metric to your metrics board, follow these steps:
- Go to the
Performance
dashboard
in the Firebase console.
- Click an empty metric card, then select an existing metric to add to your board.
- Click
more_vert
on a populated metric card for more options,
for example to replace or remove a metric.
The metrics board shows collected metric data over time, both in graphical form and as a
numerical percentage change.
Learn more about
using the dashboard
.
View traces and their data
To view your traces, go to the
Performance
dashboard
in the Firebase console, scroll down to the traces table, then click the appropriate subtab.
The table displays some top metrics for each trace, and you can even sort the list by the
percentage change for a specific metric.
Performance Monitoring provides a troubleshooting page in the Firebase console that highlights metric
changes, making it easy to quickly address and minimize the impact of performance issues on your
apps and users. You can use the troubleshooting page when you learn about potential
performance issues, for example, in the following scenarios:
- You select relevant metrics on the dashboard and you notice a big delta.
- In the traces table you sort to display the largest deltas at the top, and you see a
significant percentage change.
- You receive an email alert notifying you of a performance issue.
You can access the troubleshooting page in the following ways:
- On the metric dashboard, click the
View metric details
button.
- On any metric card, select
more_vert
=> View details
. The troubleshooting page displays information about the metric
you selected.
- In the traces table, click a trace name or any metric value in the row associated with that
trace.
- In an email alert, click
Investigate now
.
When you click a trace name in the traces table, you can then drill down into metrics of
interest. Click the
Filter
add
button to filter the data
by attribute, for example:
- Filter by
App version
to view data about a past release or your latest release
- Filter by
Device
to learn how older devices handle your app
- Filter by
Country
to make sure your database location isn't affecting a specific
region
Learn more about
viewing data for your
traces
.
Next Steps
Learn more about
using attributes
to examine performance data.
Learn more about how to
track performance issues
in the
Firebase console.
Set up alerts
for code changes that are degrading
the performance of your app. For example, you can configure an email alert for
your team if your app start time exceeds a threshold that you set.
- View detailed reports of
user sessions
in which
you can see a specific trace in a timeline context of other traces collected during the same
session.