Why the logstash running so slowly?

hi everyone,
I found the logstash running my conf file so slowly,Anyone has an solution? My conf file is very easy.

a. stdin.conf contents is input {
stdin {
add_field => {"key" => "value"}
codec => "plain"
tags => ["add"]
type => "std"
}
}
output{
stdout {codec => rubydebug}

}

b. the logstash orders is no problem.

./logstash -t -f stdin.conf
Configuration OK

c.when I input the hello world in console, it is running ...
"hello world"
Settings: Default pipeline workers: 4

I'm waiting along time,there is no result for me! what's the problems?

Best Regards,
Levi

Run it with --debug flag, it could help.

BTW, you want to add field in a String object (the codec => plain), I am not sure this can work.

it's works after I add the -- debug flag. thank you!

it's works after I add the -- debug flag. thank you!

I can't imagine that the --debug option had anything to do with this. It is, however, a very useful debugging aid.

BTW, you want to add field in a String object (the codec => plain), I am not sure this can work.

It can. The input codec just affects how the input payload is decoded (if at all). The resulting event can always have multiple fields.