Does high MergeFactor cause OOM?

["L.T." <jc...@leo18.com>]

My company has setup a DMS developed by a 
software house. We know that it's embedded 
with Jackrabbit 1.5.3.
About one year ago, the vendor increased 
the MergeFactor to 30 because we reported 
the performance became worse. Actually, 
after the change, we didn't notice any 
significant improvement.
In these few months, we found the system 
sometimes reports OOM (java heap space). 
It usually happens when using the batch 
import function of our DMS. After reading 
some articles about merging of 
jackrabbit,I suspect that the increased 
MergeFactor may be the cause of OOM.
Is it possible?
And could we get rid of the OOM problem by 
lowering the setting?