Super TTC font seems to be slow to load

[caizixian]

Examples include

• https://github.com/be5invis/Sarasa-Gothic/releases
• https://github.com/be5invis/Iosevka/blob/v33.3.0/doc/PACKAGE-LIST.md

luaotfload-tool -u takes more than 10 minutes and still hasn't finished. If I remove these SuperTTC fonts from my system, then luaotfload-tool -u finishes in under 1 minute.

[lemmi]

I have the same problem. The process is stuck working on /usr/share/fonts/TTF/IosevkaSlab.ttc for ages.

...
luaotfload | db : Loading font /usr/share/fonts/TTF/wqy-microhei.ttc
luaotfload | db : Loading font /usr/share/fonts/TTF/IosevkaSlab.ttc

Had to cancel for the moment, so I could finish my work and put this in my ~/.config/luaotfload/luaotfload.conf:

[db]
    formats = ttf,otf

[lemmi]

I let it run to see what happens and the process finished for me after almost 45 minutes on a modern zen5 machine.