Query response opt (apache#13420)

pinot-broker/src/main/java/org/apache/pinot/broker/api/resources/PinotClientRequest.java

@@ -53,6 +53,7 @@
 import javax.ws.rs.core.HttpHeaders;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
+import javax.ws.rs.core.StreamingOutput;
 import org.apache.http.conn.HttpClientConnectionManager;
 import org.apache.pinot.broker.api.HttpRequesterIdentity;
 import org.apache.pinot.broker.requesthandler.BrokerRequestHandler;
@@ -374,6 +375,7 @@ static Response getPinotQueryResponse(BrokerResponse brokerResponse)
     // returning the Response with OK status and header value.
     return Response.ok()
         .header(PINOT_QUERY_ERROR_CODE_HEADER, queryErrorCodeHeaderValue)
-        .entity(brokerResponse.toJsonString()).build();
+        .entity((StreamingOutput) brokerResponse::toOutputStream).type(MediaType.APPLICATION_JSON)
+        .build();
   }
 }

pinot-common/src/main/java/org/apache/pinot/common/response/BrokerResponse.java

@@ -20,6 +20,7 @@
 
 import com.fasterxml.jackson.annotation.JsonIgnore;
 import java.io.IOException;
+import java.io.OutputStream;
 import java.util.List;
 import java.util.Map;
 import javax.annotation.Nullable;
@@ -41,6 +42,14 @@ default String toJsonString()
     return JsonUtils.objectToString(this);
   }
 
+  /**
+   * Write the object JSON to the output stream.
+   */
+  default void toOutputStream(OutputStream outputStream)
+      throws IOException {
+    JsonUtils.objectToOutputStream(this, outputStream);
+  }
+
   /**
    * Returns the result table.
    */

pinot-spi/src/main/java/org/apache/pinot/spi/utils/JsonUtils.java

@@ -38,6 +38,7 @@
 import java.io.FileInputStream;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.OutputStream;
 import java.nio.charset.StandardCharsets;
 import java.util.AbstractMap;
 import java.util.ArrayList;
@@ -239,6 +240,11 @@ public static String objectToString(Object object)
     return DEFAULT_WRITER.writeValueAsString(object);
   }
 
+  public static void objectToOutputStream(Object object, OutputStream outputStream)
+      throws IOException {
+    DEFAULT_WRITER.writeValue(outputStream, object);
+  }
+
   public static String objectToPrettyString(Object object)
       throws JsonProcessingException {
     return DEFAULT_PRETTY_WRITER.writeValueAsString(object);