Back to Back Wait activities and/or First activity as Wait activity in a Journey

As a best practice, it is recommended to avoid a Wait activity as a first activity especially when there is a huge volume injection into the Journey. The delay issue had occurred as a result of a few million injections into a 5 hour Wait activity occurring simultaneously. When this concurrency of injection into Wait Activities occurred, it resulted in contacts not passing through steps as quickly as they were expected to. This back to back queueing causes performance issues like this Version 3 encountered especially due to the volume.

Imagine ~2 Million contacts queued for injection, and they are immediately placed into another wait queue which basically causes congestion like a highway traffic halt as the time progresses. The level of affect will vary from minimal impact to larger impact depending on volume and timing.

Prevention steps suggested by our Product Engineering Team:

1. Removal of any wait activities that are the first activity within a Journey unless they are absolutely necessary. If the purpose of configuring a Wait activity is to evaluate the Goal/Exit criteria, configuring the Entry Filter is a wise workaround for better performance. Journey entry schedules within Journey Builder can also be adjusted as needed if a later start time is desired.

2. Removal of any short (less than 15 minute) Wait Activities. Wait Activities should be limited minimally 20 minutes in duration. We expect that doing this, will significantly enhance the Journey’s performance and remove variability in the time for a contact to fully complete a Journey.