[Zope] pool_size

I am having a problem with zope 2.9.4 occasionally pegging the CPU and thereafter being unusable -- there are some indications in the event log that this is related to "pool_size" being too small. Lacking any other strategy to determine the cause of the problem, I am considering experimenting increasing "pool_size" to see what effect it has. A search returns some inprecise information on how to do this. My understanding is that this can be modified in the zope.conf for the instance. Can anybody give me precise information on modifying this parameter or point me to a concise resource on configuring the zodb in general,