code: func (e *DeleteExec) Next(ctx context.Context, req *chunk.RecordBatch) error {
  	if span := opentracing.SpanFromContext(ctx); span != nil && span.Tracer() != nil {
  		span1 := span.Tracer().StartSpan("delete.Next", opentracing.ChildOf(span.Context()))
  		defer span1.Finish()
  	}
  
  	req.Reset()
  	if e.IsMultiTable {
  		return e.deleteMultiTablesByChunk(ctx)
  	}
  	return e.deleteSingleTableByChunk(ctx)
  }
docs: // Next implements the Executor Next interface.