Ecto reconnection policy

I am new to Ecto, currently I use Ecto with mysql adaptor
Here is the case I met and confuse
there are 10 worker on the top
when db have some issue, it make connection fail from ecto
then there are lots of connections created from db perspective

how could I control the connections and limit it not to hammer db?

Uhh, what kind of DB issue would cause that?