askvortsov Thanks for sharing the custom JS.
I have add into the following into the footer extension
$('document').ready(function(){flarum.core.compat['common/components/Search'].MIN_SEARCH_LEN = 2});
But it doesn't seem to work. Do you mind tell me a little more of how to use the JS?
I have make changes according to the Littlegolden's post. However, I am not able to make MySQL config changes in my sever due to restriction of the service provider. I presume the JS you provide will be do the job without changing the MySQL config. Is it right?