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erlangmnesia

How to ensure fast startup times of mnesia

Erlang with mnesia/dets is famous for it slow startup times after a crash. Basically the same issue as with fsck on older filesystems.

But I also experience slow startup times after regular shutdowns: about 8 Minutes for 250 MB on-disk data on a beefy machine.

So I have to do something special on shutdown besides typing "q()."? Is there a way to speed up startup times?

Solution

  • Things I found out so far:

    • disk_only_tables seem to result in much longer startup times than disk_tables
    • calling mnesia:create_table() with a new table type is not enough to change a table type. Use mnesia:change_table_copy_type()
    • Seems disk_only_tables don't shrink and don't load faster if you delete items.

    I solved my issue by fixing the table type issue on two tables and shrinking my database size to 4 MB.