With the latest Logitech Media Server 8.0, it now has online music library integration. However, by default, it polls the music service every hour. That is too much for my poor Raspberry Pi with only 512MB of memory and a slow CPU. Not to mention it is also running my DNS ads blocking and tunneling services.
A simple fix is to modify the polling interval (the file Plugin.pm can be found under /usr/share/perl5/Slim/Plugin/OnlineLibrary. Edit the variable POLLING_INTERVAL).
It also helps to lower the scanner priority: go to Server Settings, under Performance, change "Scanner Priority" to something lower than normal.