使用start（）函数后，在cmdline中运行的PHP暂停

from my php script I am attempting to launch a logstash parser but I am basically doing that using this command

shell_exec('Start cmd.exe @cmd /k "C:\Users\Public\logstash-5.2.1\bin\logstash -f C:\Users\Public\Documents\logstash-gpu.conf"');

This allows me to open a new cmd window and run the parser etc... but my script pauses when the new window is launched and it doesnt continue till I close the window. I tried the same command with exec and passthru and system and I always get the same result.

Is there any work around for this??

Thanks, Karan.