Sleep inside kong plugin blocking kong

We have few customer plugins written to rewrite paths/upstreams.
One of the plugin having os.execute(sleep 60).
Does this cause kong to stop accepting new requests ?

In general does Plugin execution blocks worker to accept new requests ?
We have making some API calls(using resty.http) inside plugins to featch data, and rewrite upstream/paths.

We started using ngx.sleep() which is unblocking in nature.
Now kong is not getting into unresponsive state