Logstash pipeline workers and imap input plugin

Hi,
We have configured logstash(using default pipeline configuration). We have just one pipeline running.
When I start logstash I see it has 4 pipeline workers and batch size of 125. I am using IMAP input plugin to process emails from server.

I see that all 4 workers establish connection with IMAP.

I want to know if all workers connect to IMAP endpoint, do all workers operate parallel or just 1 worker communicates?

Thanks in advance for your help.

Thanks

The worker threads do not connect to IMAP. An input thread connects to IMAP and dispatches events to a queue that the worker threads read from in parallel. The execution model is described here.