After a couple of days, when I have Safari open, I have an unexplainable high CPU load, apparently system time. launchservicesd is active with 50%-110% CPU load.
The load disappears immediately when I close Safari.
The load appears roughly one minute after I open Safari.
I have no plugins and no particular webpage open. Just the Google search page but the load is independent of opened pages or tabs.
Looking at error messages with Console I found there were thousands of messages per second. Most of them where:
Sandbox: com.apple.WebKit.WebContent(61941) deny(1) mach-lookup com.apple.diagnosticd
But this just seems to be a follow on problem of the actual problem. There were also messages about a corrupted SQLite database saying:
database disk image is malformed
without mentioning which database. There were also error messages pointing at iconservices:
/private/var/folders/<random_dirs>/C/com.apple.iconservices/store.index
Clearing all Safari caches and removing Website Cookies did not help.
fs_usage cmd Safari
Pointed me to the right direction: Some time after starting Safari there was continuous activity around /Users/ov/Library/Safari/Favicon Cache.
Deleting this cache fixed the high CPU load for me.
Solution
I deleted the cache using the following command:
sudo rm -rfv Library/Safari/Favicon\ Cache
Safari is automatically rebuilding the cache over time. The cache consists of an SQLite database, which apparently got corrupted in my setup.