Event batching

The Optimizely Full Stack Android SDK now batches impression and conversion events into a single payload before sending it to Optimizely. This is achieved through a new SDK component called the event processor.

Event batching has the advantage of reducing the number of outbound requests to Optimizely depending on how you define, configure, and use the event processor. It means less network traffic for the same number of Impression and conversion events tracked.

In the Android SDK, BatchEventProcessor provides implementation of the EventProcessor interface and batches events. You can control batching based on two parameters:

  • Batch size: Defines the number of events that are batched together before sending to Optimizely.
  • Flush interval: Defines the amount of time after which any batched events should be sent to passed to the Event Dispatcher to be sent to Optimizely.

An event consisting of the batched payload is sent as soon as the batch size reaches the specified limit or flush interval reaches the specified time limit. BatchEventProcessor options are described in more detail below.

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Note

The default Event Dispatcher in our Android SDK uses an Android Intent Service to dispatch batched requests. As a result you may observe additional delays to outbound requests beyond your specified flush interval as a result of system limits on those requests.

Optimizely's Event batching works with both out-of-the-box and custom event dispatchers.

The event batching process doesn't remove any personally identifiable information (PII) from events. You must still ensure that you aren't sending any unnecessary PII to Optimizely.

Basic example

import com.optimizely.ab.android.sdk.OptimizelyManager;
import android.support.v7.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        String sdkKey = "{SDK_KEY}";
      
        OptimizelyManager optimizelyManager = OptimizelyManager.builder()
          .withSDKKey(sdkKey)
          .build(getApplicationContext());
        Optimizely optimizely = optimizelyManager.initialize(MainActivity.this, R.raw.datafile);
    }
}

By default, batch size is 10 and flush interval is 30 seconds.

Advanced Example

import com.optimizely.ab.android.sdk.OptimizelyManager;
import com.optimizely.ab.android.sdk.OptimizelyClient;
import com.optimizely.ab.event.BatchEventProcessor;
import java.util.concurrent.TimeUnit;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
      String sdkKey = "{SDK_KEY}";
      EventHandler eventHandler = DefaultEventHandler.getInstance(context);

      // Here we are using the builder options to set batch size
      // to 5 events and flush interval to a minute.
      BatchEventProcessor batchProcessor = BatchEventProcessor.builder()
        .withBatchSize(5)
        .withEventHandler(eventHandler)
        .withFlushInterval(1, TimeUnit.MINUTES)
        .build();
        
      OptimizelyManager optimizelyManager = OptimizelyManager.builder()
        .withSDKKey(sdkKey)
        .withEventHandler(eventHandler)
        .withDatafileDownloadInterval(15L, TimeUnit.MINUTES)
        .withEventProcessor(batchProcessor)
        .build(getApplicationContext());
      
      OptimizelyClient optimizely = optimizelyManager.initialize(getApplicationContext(), R.raw.datafile);
    }
}

BatchEventProcessor

BatchEventProcessor is an implementation of EventProcessor where events are batched. The class maintains a single consumer thread that pulls events off of the BlockingCollection and buffers them for either a configured batch size or a maximum duration before the resulting LogEvent is sent to the EventDispatcher and NotificationCenter.

The following properties can be used to customize the BatchEventProcessor configuration using the Builder class

Builder methods

Use the following methods to customize the BatchEventProcessor.

Property

Default value

Description

withEventHandler

null

Required field. Specifies event handler to use to dispatch event payload to Optimizely.

By default, if you create an Optimizely instance, it passes in AsyncEventHandler to BatchEventProcessor.

withBatchSize

10

The maximum number of events to batch before dispatching. Once this number is reached, all queued events are flushed and sent to Optimizely.

withFlushInterval

30000 (30 Seconds)

Maximum time after which to batch and send event payload to Optimizely. In milliseconds.

withEventQueue

1000

BlockingCollection that queues individual events to be batched and dispatched by the executor.

withNotificationCenter

null

Notification center instance to be used to trigger any notifications to notify when event batches are flushed.

withExecutor

Single Thread Executor

Executor service that takes care of triggering event batching and subsequent dispatching to Optimizely.

withTimeout

5000

Maximum time to wait for event processor’s close to be executed. In milliseconds.

Advanced configuration

You can set the following properties can be set to override the default configuration for BatchEventProcessor.

event.processor.batch.size

10

Maximum size of batch of events to send to Optimizely.

event.processor.batch.interval

30000

Maximum time after which to batch and send event payload to Optimizely. In milliseconds.

event.processor.close.timeout

5000

Maximum time to wait for event processor’s close to be executed. In milliseconds.

For more information, see Initialize SDK.

Side effects

The table lists other Optimizely functionality that may be triggered by using this class.

Functionality

Description

LogEvent

Whenever the event processor produces a batch of events, a LogEvent object will be created using the EventFactory.
It contains batch of conversion and impression events.
This object will be dispatched using the provided event dispatcher and also it will be sent to the notification subscribers

Notification Listeners

Flush invokes the LOGEVENT notification listener if this listener is subscribed to.

Registering LogEvent listener

To register a LogEvent notification listener

optimizelyClient.getNotificationCenter().addNotificationHandler(LogEvent.class, logEvent -> {});

LogEvent

LogEvent object gets created using EventFactory. It represents the batch of impression and conversion events we send to the Optimizely backend.

Object

Type

Description

requestMethod
Required (non null)

RequestMethod (Enum)

The HTTP verb to use when dispatching the log event. It can be Get or post.

endpointUrl
Required (non null)

String

URL to dispatch log event to.

requestParams
Required (non null)

Map<String, String>

Parameters to be set in the log event.

eventBatch
Required

EventBatch

It contains all the information regarding every event which is batched. including list of visitors which contains UserEvent.

Close Optimizely on application exit

If you enable event batching, it's important that you call the Close method (optimizelyClient.close()) prior to exiting. This ensures that queued events are flushed as soon as possible to avoid any data loss.

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Important

Because the Optimizely client maintains a buffer of queued events, we recommend that you call close() on the Optimizely instance before shutting down your application or whenever dereferencing the instance.

Method

Description

close()

Stops all executor threads and flushes the event queue. This method will also stop any scheduledExecutorService that is running for the data-file manager.


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