Heap size is the amount of memory that Salesforce allocates to a process running in the system. If a job (such as an automation or email campaign process) uses too much memory, it can hit a heap size limit, causing errors or slowing down performance.

Like all third-party Salesforce applications, we will use Salesforce resources. But we have tuned our product so that it works within the limits Salesforce sets. A heap size issue can occur for several reasons. However, typically, it is due to a process that interacts with our code in the same transaction.

We generally ask that you review any custom code or triggers that you might have to make sure they work in batch. On our side, we can tune settings when we have granted access. For example, if the error mentions BatchMailingRates (the job that calculates email open and click rates), we can lower Email Rates Batch Size from the default of 500 to 200. Or we can turn off things like audit.

Common Errors

Some heap and CPU limit errors fix themselves. When one of the jobs below fails for that reason, the app cuts that job's batch size in half for the next run. The failed run is not retried, so the change takes effect the next time the job runs.

• Import Wizard report imports (ReportToListBatch): sends rows from a Salesforce report to a Campaign Monitor list. Setting: Import Wizard Batch Size.

• Primary sync subscriber pull (CMBatchSubscriber): brings subscriber list membership from Campaign Monitor into Salesforce. Setting: Get Subscriber Page Size.

• Email opt out sync (CMBatchEmailOptOut): marks contacts and leads as opted out when they are unsubscribed from all lists. Setting: Email Opt Out Batch Size.

BatchMailingRates is not adjusted automatically. If you see a heap error for it, lower Email Rates Batch Size yourself under Governor Limits (the cog icon on the Maintenance page), or contact support.

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