On Opportunity there are two lookups fields, the standard Primary Campaign Source, and a custom lookup to object Exhibition__c (which is set to Clear the value of this field if related record is deleted). So in theory, these should not cause any row lock issues, right? The company uses 1 campaign per year and one 1 Exhibition__c record per year with over 100k Opportunities. I am aware this is not best practice, but I am trying to understand the technical issues caused by this.
What will having this lookup skew produce? Is it simply processing time?