Warning: read ‘answer’ as ‘seems to make a difference’
I don’t see the issue happen if I change the controller block to look like:
begin
#...
while true do
t = Thread.new do #<<<<<<<<<<<<<<<<<
ActiveRecord::Base.connection_pool.with_connection do |conn|
#...
end
end
t.join #<<<<<<<<<<<<<<<<<
end
#...
rescue IOError
#...
But I don’t know whether this has actually solved the problem or just made it extremely unlikely. Nor can I really fathom why this would make a difference.
Posting this as a solution in case it helps, but still digging on the issue.