Very slow responses to rtags commands

[przecze]

I have rtags and vim-rtags installed on my Ubuntu 18.10.
When I issue a rtags mapping in vim, like <leader>rj, called function appears immediately in vim command line like this :call rtags#JumpTo(g:SAME_WINDOW).
I also see the command appearing immediately in rdm logs: rc --absolute-path -f /home/przemek/path/to/file.cpp:375:18
If I issue the same command in terminal instead of vim, I get the answer immidiately.
However in vim I have to wait ages for the result. I'm not even sure if it's always successful, or I need to wait longer.
Funny thing, this issue sometimes appear and after sometime it works normally again. I don't have any heavy cpu load. Can this be a issue in connection to rdm? Maybe some other process is interfering with it?

[mckellyln]

I have seen this in the past also and wondered if there was possibly a race with obtaining vim channel output.
I think I improved it somewhat in my fork of vim-rtags - but it really should be re-visited.