Module output_requirements 

The GlobalOrderRequire optimizer rule either:

• Adds an auxiliary OutputRequirementExec operator to keep track of global ordering and distribution requirement across rules, or
• Removes the auxiliary OutputRequirementExec operator from the physical plan. Since the OutputRequirementExec operator is only a helper operator, it shouldn’t occur in the final plan (i.e. the executed plan).

Structs

OutputRequirementExec

An ancillary, non-executable operator whose sole purpose is to track global requirements during optimization. It imposes

OutputRequirements

This rule either adds or removes OutputRequirementss to/from the physical plan according to its mode attribute, which is set by the constructors new_add_mode and new_remove_mode. With this rule, we can keep track of the global requirements (ordering and distribution) across rules.