Figure 3. Details about each allocated object appear in the Instance View on the right. You can use the two menus above the list of allocated objects to choose which heap to inspect and how to organize the data. To improve app performance while profiling, the memory profiler samples memory allocations periodically by default.
When testing on devices running API level 26 or higher, you can change this behavior by using the Allocation Tracking dropdown. The options available are as follows:. JNI references are managed manually by the native code, so it is possible for Java objects used by native code to be kept alive for too long.
Some objects on the Java heap may become unreachable if a JNI reference is discarded without first being explicitly deleted. Also, it is possible to exhaust the global JNI reference limit. With this information, you can find when and where global JNI references are created and deleted. While your app is running, select a portion of the timeline that you want to inspect and select JNI heap from the drop-down menu above the class list. You can then inspect objects in the heap as you normally would and double-click objects in the Allocation Call Stack tab to see where the JNI references are allocated and released in your code, as shown in figure 4.
Figure 4. Viewing global JNI references. The Android Studio Memory Profiler includes a Native Memory Profiler for apps deployed to physical devices running Android 10; support for Android 11 devices is currently available in the Android Studio 4.
To initiate a recording, click Record native allocations at the top of the Memory Profiler window:. By default, the Native Memory Profiler uses a sample size of 32 bytes: Every time 32 bytes of memory are allocated, a snapshot of memory is taken. A smaller sample size results in more frequent snapshots, yielding more accurate data about memory usage. A larger sample size yields less accurate data, but it will consume fewer resources on your system and improve performance while recording.
A heap dump shows which objects in your app are using memory at the time you capture the heap dump. Especially after an extended user session, a heap dump can help identify memory leaks by showing objects still in memory that you believe should no longer be there.
To capture a heap dump, click Dump Java heap in the Memory Profiler toolbar. While dumping the heap, the amount of Java memory might increase temporarily. This is normal because the heap dump occurs in the same process as your app and requires some memory to collect the data.
The heap dump appears below the memory timeline, showing all class types in the heap, as shown in figure 5. Figure 5. Viewing the heap dump. If you need to be more precise about when the dump is created, you can create a heap dump at the critical point in your app code by calling dumpHprofData. Native Size : Total amount of native memory used by this object type in bytes. This column is visible only for Android 7.
You will see memory here for some objects allocated in Java because Android uses native memory for some framework classes, such as Bitmap. Retained Size : Total size of memory being retained due to all instances of this class in bytes. You can use the two menus above the list of allocated objects to choose which heap dumps to inspect and how to organize the data. The list is sorted by the Retained Size column by default. To sort by the values in a different column, click the column's heading.
Click a class name to open the Instance View window on the right shown in figure 6. Each listed instance includes the following:.
Figure 6. The duration required to capture a heap dump is indicated in the timeline. Or, click the arrow next to the instance name to view all its fields, and then click a field name to view all its references. If you want to view the instance details for a field, right-click on the field and select Go to Instance. After you capture a heap dump, the data is viewable in the Memory Profiler only while the profiler is running.
When you exit the profiling session, you lose the heap dump. In Android Studio 3. In the Export As dialog that appears, save the file with the. For example:. When analyzing a heap dump in the Memory Profiler, you can filter profiling data that Android Studio thinks might indicate memory leaks for Activity and Fragment instances in your app. To use this feature, first capture a heap dump or import a heap dump file into Android Studio.
Figure 7. Filtering a heap dump for memory leaks. While using the Memory Profiler, you should stress your app code and try forcing memory leaks. One way to provoke memory leaks in your app is to let it run for a while before inspecting the heap. Leaks might trickle up to the top of the allocations in the heap. A Complete Set of Behavioral Data. Stickier Digital Experiences. Accelerated Decision-Making. Digital Experience Insights Report, Installation 2. See what else you might be missing.
A lot, turns out. Download Report. Used and loved by fast-moving digital teams everywhere. View all customer stories. A fatal exception will occur when the watchpoint triggers. If you can find the function which allocates memory with an address immediately before the address which is corrupted, this will probably be the function which overflows the buffer.
Temporarily increasing the heap corruption detection level can give more detailed information about heap corruption errors. In the project configuration menu, under Component config there is a menu Heap memory debugging. This is the default level. This usually indicates a buffer overrun or out of bounds write. If assertions are enabled, an assertion will also trigger if a double-free occurs the same memory is freed twice. If an application writes outside the bounds of allocated buffers, the canary bytes will be corrupted and the integrity check will fail.
With Basic heap checks, the number of overrun bytes before a failure is detected will depend on the properties of the heap. Each time free is called in Light Impact mode, the head and tail canary bytes of the buffer being freed are checked against the expected values.
In both cases, the check is that the first 4 bytes of an allocated block before the buffer returned to the user should be the word 0xABBA Then the last 4 bytes of the allocated block after the buffer returned to the user should be the word 0xBAAD In this mode, all freshly allocated memory is filled with the pattern 0xCE, and all freed memory is filled with the pattern 0xFE.
However it allows easier detection of memory corruption bugs which are much more subtle to find otherwise. It is recommended to only enable this mode when debugging, not in production. The application should be changed to either use calloc which zeroes memory , or initialize the memory before using it.
The application should be changed to not access heap memory after it has been freed. If a call to malloc or realloc causes a crash because it expected to find the pattern 0xFEFEFEFE in free memory and a different pattern was found, then this indicates the app has a use-after-free bug where it is writing to memory which has already been freed.
In each case the checker is expecting to find a given pattern, and will error out if this is not found:. For free heap blocks, the checker expects to find all bytes set to 0xFE. Any other values indicate a use-after-free bug where free memory has been incorrectly overwritten. Within this view, you can gain context on what the property is by reading the property notes and seeing a preview of the common values for this property in your dataset.
You can also see the current visibility state of the property personal or shared and its data type in Heap. You cannot modify the data type of certain properties that are native to Heap, such as autocaptured client-side properties and source properties. By default, Heap will automatically try to assess the property type when the data type is set to Auto-Detect. However, in certain cases, you may want to manually specify how Heap should treat the property in analysis by changing the data type.
This allows Heap to perform mathematical aggregations on dollar amounts or prevents Heap from bucketing unique identities when your internal ID is a number. For a full list of all autocaptured properties in Heap for web and mobile, see Autocaptured Data.
For example, you can use the addUserProperties API to assign custom properties to any of your users from your servers, such as account-level information from your database, or demographic info. See our API docs for information on how to set up custom properties. You can define new properties based on existing property values in Heap from the properties page and via property suggestions in the Event Visualizer. This allows you to define a new virtual schema on top of your existing dataset for specific use cases that require custom groupings of property values.
Some popular use cases for defined properties include:. If you plan on using Heap Connect to sync defined properties, note that there is a character limit in the data schema. For this reason, we recommend keeping all defined property values below characters.
When you define an event in the Event Visualizer , if data attributes are present on the event, Heap will provide Property Suggestions associated with the event that you can choose to add to your event definition. To define a new property in Heap, click the New Definition button in the top right corner of the Properties page and select New Property. This will launch the property creator, as seen below. Team members in the Read-Only and Consumer role can only create personal properties.
Analysts, Architects, and Admins can create shared properties using the visibility toggle in the top-right. As referenced in the name, conditional properties are defined by the conditions applied to them.
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