How can I check if a log file was analyzed by logstash or not?

I found one of my log is missing in elasticsearch, how can I know if logstash analyzed it or not? or how can I know what problem logstah meet? In logstash-plain.log the information is limited, there is no information about which file logstash analyzed.

why no one check my question?

I think you'd need to provide a bit more information here for someone to be able to help.

What does your config look like? If it's too large, then just the input section that should have processed the file in question would help.