Nereids(new optimizer) code base
Nereids is new query planner for Doris. It include three main parts: parser, analyzer and optimizer.
The parser, generated by ANTLR4, transforms SQL into a logical plan with a tree structure. Analysis and optimization are performed on the logical plan of the tree structure. Each transformation is defined as a rule. The rule is applied to the logical plan using pattern matching. The implementation of the optimizer follows the approach in the Cascades paper.
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