Add progress bar on --render

[lasconic]

Also uses multiprocess.Pool instead of Process. It's twice faster !

[BoboTiG]

I do not know yet how to deal with this regression: context.close_ctx() is never called in --render.
The context setup being done at pool init, we then loose control to call close() at the end of the pool.

Do you have an idea how to deal with it?

[lasconic]

Is it really a problem ? context.init installs a "atexit" to close the context (and the db). That should be per process.

[BoboTiG]

It is on the multilingual side, since another locale trying to open the DB with uncomitted changes will throw an error. I'm not really sure about the root cause, but having the DB properly closed could be better to start.

[BoboTiG]

I logged when setup_*() and close_ctx() are called: close_ctx() is simply never called.

EDIT: it varies, sometimes it's called, sometimes not. I guess this is related to when stdout is still available at interpreter exit. But I'm sill seeing the DB not closed at exit anyway.

[BoboTiG]

Forget it, I must have broken the DB somehow. I'll retry from a fresh ground.