What minimal characteristics shall TimeSeries DataStore have?

I'm just wondering, according to general perception... How shall a TimeSeries DataStore behave to be efficient and what minimal characteristics it shall have?

I'm mid-way working on a TimeSeries DataStore implemented in GoLang utilizing power of LevelDB at back.

Yes, I know there are awesome TSDB implementations which are out there and I should have used. I did try to read-up a lot... either they looked limited, slow or bulky. And most importantly this project let me try my idea of having a simple, fast TimeSeries DataStore specific to my requirement of it.