<https://stackoverflow.com/posts/68108655/timeline>
I have read the design doc of the Flink planner recently. I've found the Flink only uses Calcite as an SQL optimizer. It translates an optimized RelNode to Flink（or Blink）RelNode, and then transfers it to the physical plan. Why doesn't Flink implement Calcite adapters? Isn't this an easier way to use calcite? The link of calcite daptor:calcite.apache.org/docs/adapter.html.
