@Override
    protected IrRowPattern visitIrExclusion(IrExclusion node, Boolean inExclusion) {
      IrRowPattern child = process(node.getPattern(), true);
      if (inExclusion) {
        // skip nested exclusion. this is necessary to resolve exclusions correctly during pattern
        // matching
        return child;
      }

      return new IrExclusion(child);
    }
Optimize row pattern: - remove nested exclusions - flatten alternations and concatenations -
remove redundant empty pattern
iotdb-core/datanode/src/main/java/org/apache/iotdb/db/queryengine/plan/relational/planner/rowpattern/IrRowPatternFlattener.java