We recently started experiencing repeatedly long sync cycles between Marketo and SFDC (taking between 1 to 8 hours).
We've been investigating and found that DiscoverOrg does a nightly update process to any SFDC record with a DiscoverOrg Id. That update process updates the mod stamp in SFDC every night. That mod stamp update causes Marketo to sync the record. So each day Marketo is syncing 150,000 records which is causing each sync cycle to take hours to complete.
We are going through and hiding unnecessary fields from the Marketo>SFDC sync to try and speed things up, but the real issue is the frequency of updates to the mod stamp on every record.
Has anyone experienced this kind of issue? Have any suggested solutions?