MRU-cache is not thread safe

[guicho271828]

Around here: https://github.com/dmitryvk/cl-sqlite/blob/master/cache.lisp#L24
How I can disable it?

[guicho271828]

perhaps I should get a handle from each thread.

[dmitryvk]

SQLite is itself non thread-safe w.r.t. single database handle (i.e., each thread should open its own handle to the database). So it does not make much sense to make the cache thread-safe.
Each thread should open its own database handle.

[guicho271828]

I agree. It worked with multiple database handles.
I think giving a brief reference in the doc may be helpful.