Trying to track down why PHP Max_Children is being hit

I have a site that I seem to be getting a lot of PHP max_children errors, happens more frequenlty when I send out newsletters.

The only thing that I can think of that could be causing a problem is potentially relationship field usage? It seems to be worse with a certain newsletter that I used relationship fields to make selecting the newsletter’s entries easier. Other 2 sites / newsletters are built using the multi-site feature.

The host (Nexcess) has been trying to help me figure it out, and can’t seem to find the issue other than its entry sql queries.

Its a big database of entries, probably 60,000 or more (I haven’t looked at the total in a while)