Issue
Customers may see their Engage Audience stuck in a "Preparing" status or see a banner stating: "This audience is temporarily locked by a previous edit or disabling operation.". The sync to the destination may appear to take several days, even when a manual calculation (total audience records divided by the destination's requests per second limit) suggests the sync should only take minutes or a few hours.
Product
Segment
Environment
Segment Console
Cause
Calculating sync time by simply dividing the final audience size by the destination's requests per second (RPS) limit misses several backend architectural factors that multiply the processing time:
- Shared Rate Limits: Engage rate limits are set at the space-destination level. Every audience or computed trait in the space that is linked to that specific destination shares the exact same rate limit bandwidth.
- Candidate User Evaluation (Preload): During an initial computation or historical backfill, Segment must send all users who even partially qualify for the audience into the real-time engine to preserve their state. The engine must backfill and evaluate all candidate users matching at least one criterion, which can mean processing hundreds of millions of profiles to reach the final audience size.
- Syncing Exits: The backfill process must also sync "exits" downstream for users who previously qualified for the audience but no longer do. These exit events are constrained by the same shared destination rate limit.
- Internal Throttling: Because destinations do not throttle events on their own, the destination's rate limit is imposed on Engage when generating the events. This low rate limit restricts how fast Engage can evaluate and add users to the audience internally.
Resolution
- Wait for the initial backfill and sync to complete. Segment recommends waiting at least 24 hours for an audience to finish computing, though it can take longer depending on the destination rate limit and system concurrency.
- Avoid editing the audience definition or disabling/re-enabling it while it is locked. Editing an audience that includes historical event data creates a new backfill task, which is further delayed by rate-limited destinations.
- For workspaces using legacy destinations with strict rate limits (for example, Salesforce Marketing Cloud is limited to 20 RPS), migrate to the newer Actions framework destinations. Actions destinations support batch requests, which bypass legacy API constraints and drastically reduce backfill times.
Additional Information
Segment has a strict edit concurrency limit; you can only edit five concurrent audiences or computed traits at a time. Once this limit is reached, Segment queues and locks additional computations with a "Preparing" status until one of the active tasks finishes computing.