CRM Online AsyncOperationBase

I have been provided with the top 10 tables used by my CRM online instance . The biggest table is the AsyncOperationBase which is 8 Gig in size. I regularly archive my Process Sessions and System job logs so I am a little confused why this table is so large. I dont have many waiting jobs so could someone enlighten me why this table is eating up most of my Online system space and can I get Microsoft to do anything?

Thanks G