By pitch black night I mean for example cloudy with stars, there is always some light.
Not that it matters, but isn't that a contradiction! :-) "Pitch Black" means no useful light at all.
If you use ISO 12800 and a F1.4 lens you can get far with a one second exposure, but the camera's light meter won't go that low.
I had a reply from Canon's product specialist confirming this. Even with the 1Dx or D4 the limitation is there.
That is well documented in every camera's User Manual. There are some small differences of course, but for example the Nikon D4 is specified for Matrix or Center Weighted metering from -1 to +20 EV. For Spot metering the range is 0 to +20 EV. (For whatever it's worth, that is improved on all models from the D1 through the D3S which had a range of 0 to +20 EV, except wtih spot metering which was +2 to +20 EV and is unchanged.)
It absolutely would be possible to extend the metering range lower, but if that significantly increases the size, the weight, or the price of the camera it won't be done because the camera would not be marketable.
What irritates me is that the camera can show me a histogram after the exposure which is veeery heavy on the left side.
So it can measure the exposure correctly in the file, if only it could use this information for taking a second exposure...
Stop and analyze what you have there! The image sensor and the metering sensor are two different things, and you absolutely don't want a camera, using current technology, that does it differently. However, if you open your mind and leave old biases behind, there is a very clear path to nirvana here!
Stop thinking as you would with film, where pressing the shutter release and making an exposure has financial cost. With a digital camera it doesn't. Start thinking of your camera's shutter release button as a dual function tool. First you press it to activate the extremely sophisticated light meter and data readout system incorporated in the camera! That (specifically the Hightlight and Histogram displays) will provide better exposure information than any other "light meter" you can find today. Once you've made use of the light meter tool, switch (in your mind) to image capture mode and if necessary (noting that it might not be required because that light meter did capture an image incidental to making a reading) activate the shutter release to get the desired image data capture. (You also have the option of using the on camera photograph generator to make that into a picture immediately, or you can do that in post processing later.)
It's not any lack of camera functionality causing the problem! It's the mindset that a digitial camera is only a replacement for a film camera, and therefore using it as one would a film camera. They aren't the same thing, and assuming they are loses a great deal of functionality.
Granted that does not help much, other than understanding why it is what it is, with y0ur OP about automatic operation. It's a simple case that your light levels are lower than the functional range of the camera's light meter.