Literature on physical algebra

For a database system, one needs a query language. I have this. One also needs a logical algebra to provide a starting point for query optimization. I also have this. But for actually doing query optimization, one needs a physical algebra. I still need the physical algebra.

Can you recommend any literature which tells me how to define this kind of thing and what would be a good formalism to define the physical algebra?

People have mentioned the phrase `attributed grammar' in this context...

tia,
kai

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Linux provides a nice `poweroff' command, but where is `poweron'?