Motivation:

• This allows us to see the difference between the best plan enumerated vs the actual plans chosen by multiplanner/CBR.
• This allows to see the performance difference between the plans enumerated to assess how meaningful the choice made by the plan ranker is.

Requirements:

• expose the QuerySolution hash in explain as a new field: solutionHash.
• add a parameter to find that runs a particular plan.
• Add an internal knob that prevent users from using the above features.