Add Calcite Avatica protobuf handler (#10543)

codestyle/spotbugs-exclude.xml

@@ -38,6 +38,12 @@
             </Or>
         </And>
     </Match>
+    <Match>
+        <And>
+            <Bug pattern="SE_BAD_FIELD_STORE" />
+            <Class name="org.apache.druid.server.AsyncQueryForwardingServlet" />
+        </And>
+    </Match>
 
     <Bug pattern="AT_OPERATION_SEQUENCE_ON_CONCURRENT_ABSTRACTION"/>
     <Bug pattern="BC_UNCONFIRMED_CAST"/>

docs/querying/sql.md

@@ -954,6 +954,14 @@ try (Connection connection = DriverManager.getConnection(url, connectionProperti
 }
 ```
 
+It is also possible to use a protocol buffers JDBC connection with Druid, this offer reduced bloat and potential performance
+improvements for larger result sets. To use it apply the following connection url instead, everything else remains the same
+```
+String url = "jdbc:avatica:remote:url=http://localhost:8082/druid/v2/sql/avatica-protobuf/;serialization=protobuf";
+```
+
+> The protobuf endpoint is also known to work with the official [Golang Avatica driver](https://github.com/apache/calcite-avatica-go)
+
 Table metadata is available over JDBC using `connection.getMetaData()` or by querying the
 ["INFORMATION_SCHEMA" tables](#metadata-tables).
 

integration-tests/src/test/java/org/apache/druid/tests/security/AbstractAuthConfigurationTest.java

@@ -34,7 +34,7 @@ import org.apache.druid.java.util.http.client.CredentialedHttpClient;
 import org.apache.druid.java.util.http.client.HttpClient;
 import org.apache.druid.java.util.http.client.auth.BasicCredentials;
 import org.apache.druid.java.util.http.client.response.StatusResponseHolder;
-import org.apache.druid.sql.avatica.DruidAvaticaHandler;
+import org.apache.druid.sql.avatica.DruidAvaticaJsonHandler;
 import org.apache.druid.testing.IntegrationTestingConfig;
 import org.apache.druid.testing.clients.CoordinatorResourceTestClient;
 import org.apache.druid.testing.utils.HttpUtil;
@@ -285,12 +285,12 @@ public abstract class AbstractAuthConfigurationTest
 
   String getBrokerAvacticaUrl()
   {
-    return "jdbc:avatica:remote:url=" + config.getBrokerUrl() + DruidAvaticaHandler.AVATICA_PATH;
+    return "jdbc:avatica:remote:url=" + config.getBrokerUrl() + DruidAvaticaJsonHandler.AVATICA_PATH;
   }
 
   String getRouterAvacticaUrl()
   {
-    return "jdbc:avatica:remote:url=" + config.getRouterUrl() + DruidAvaticaHandler.AVATICA_PATH;
+    return "jdbc:avatica:remote:url=" + config.getRouterUrl() + DruidAvaticaJsonHandler.AVATICA_PATH;
   }
 
   void verifyAdminOptionsRequest()

server/pom.xml

@@ -319,6 +319,10 @@
             <groupId>com.fasterxml.jackson.module</groupId>
             <artifactId>jackson-module-guice</artifactId>
         </dependency>
+        <dependency>
+            <groupId>org.apache.calcite.avatica</groupId>
+            <artifactId>avatica-core</artifactId>
+        </dependency>
 
         <!-- Tests -->
         <dependency>
@@ -450,11 +454,6 @@
             <version>1.3</version>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>org.apache.calcite.avatica</groupId>
-            <artifactId>avatica-core</artifactId>
-            <scope>test</scope>
-        </dependency>
     </dependencies>
 
     <build>

server/src/main/java/org/apache/druid/server/AsyncQueryForwardingServlet.java

@@ -26,6 +26,10 @@ import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableMap;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
+import org.apache.calcite.avatica.remote.ProtobufTranslation;
+import org.apache.calcite.avatica.remote.ProtobufTranslationImpl;
+import org.apache.calcite.avatica.remote.Service;
+import org.apache.commons.io.IOUtils;
 import org.apache.druid.client.selector.Server;
 import org.apache.druid.guice.annotations.Json;
 import org.apache.druid.guice.annotations.Smile;
@@ -118,6 +122,7 @@ public class AsyncQueryForwardingServlet extends AsyncProxyServlet implements Qu
   private final RequestLogger requestLogger;
   private final GenericQueryMetricsFactory queryMetricsFactory;
   private final AuthenticatorMapper authenticatorMapper;
+  private final ProtobufTranslation protobufTranslation;
 
   private HttpClient broadcastClient;
 
@@ -145,6 +150,7 @@ public class AsyncQueryForwardingServlet extends AsyncProxyServlet implements Qu
     this.requestLogger = requestLogger;
     this.queryMetricsFactory = queryMetricsFactory;
     this.authenticatorMapper = authenticatorMapper;
+    this.protobufTranslation = new ProtobufTranslationImpl();
   }
 
   @Override
@@ -191,9 +197,16 @@ public class AsyncQueryForwardingServlet extends AsyncProxyServlet implements Qu
     // them as a generic request.
     final boolean isQueryEndpoint = requestURI.startsWith("/druid/v2") && !requestURI.startsWith("/druid/v2/sql");
 
-    final boolean isAvatica = requestURI.startsWith("/druid/v2/sql/avatica");
+    final boolean isAvaticaJson = requestURI.startsWith("/druid/v2/sql/avatica");
+    final boolean isAvaticaPb = requestURI.startsWith("/druid/v2/sql/avatica-protobuf");
 
-    if (isAvatica) {
+    if (isAvaticaPb) {
+      byte[] requestBytes = IOUtils.toByteArray(request.getInputStream());
+      Service.Request protobufRequest = this.protobufTranslation.parseRequest(requestBytes);
+      String connectionId = getAvaticaProtobufConnectionId(protobufRequest);
+      targetServer = hostFinder.findServerAvatica(connectionId);
+      request.setAttribute(AVATICA_QUERY_ATTRIBUTE, requestBytes);
+    } else if (isAvaticaJson) {
       Map<String, Object> requestMap = objectMapper.readValue(
           request.getInputStream(),
           JacksonUtils.TYPE_REFERENCE_MAP_STRING_OBJECT
@@ -456,6 +469,95 @@ public class AsyncQueryForwardingServlet extends AsyncProxyServlet implements Qu
     return (String) connectionIdObj;
   }
 
+  static String getAvaticaProtobufConnectionId(Service.Request request)
+  {
+    if (request instanceof Service.CatalogsRequest) {
+      return ((Service.CatalogsRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.SchemasRequest) {
+      return ((Service.SchemasRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.TablesRequest) {
+      return ((Service.TablesRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.TypeInfoRequest) {
+      return ((Service.TypeInfoRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.ColumnsRequest) {
+      return ((Service.ColumnsRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.ExecuteRequest) {
+      return ((Service.ExecuteRequest) request).statementHandle.connectionId;
+    }
+
+    if (request instanceof Service.TableTypesRequest) {
+      return ((Service.TableTypesRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.PrepareRequest) {
+      return ((Service.PrepareRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.PrepareAndExecuteRequest) {
+      return ((Service.PrepareAndExecuteRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.FetchRequest) {
+      return ((Service.FetchRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.CreateStatementRequest) {
+      return ((Service.CreateStatementRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.CloseStatementRequest) {
+      return ((Service.CloseStatementRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.OpenConnectionRequest) {
+      return ((Service.OpenConnectionRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.CloseConnectionRequest) {
+      return ((Service.CloseConnectionRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.ConnectionSyncRequest) {
+      return ((Service.ConnectionSyncRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.DatabasePropertyRequest) {
+      return ((Service.DatabasePropertyRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.SyncResultsRequest) {
+      return ((Service.SyncResultsRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.CommitRequest) {
+      return ((Service.CommitRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.RollbackRequest) {
+      return ((Service.RollbackRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.PrepareAndExecuteBatchRequest) {
+      return ((Service.PrepareAndExecuteBatchRequest) request).connectionId;
+    }
+
+    if (request instanceof Service.ExecuteBatchRequest) {
+      return ((Service.ExecuteBatchRequest) request).connectionId;
+    }
+
+    throw new IAE("Received an unknown Avatica protobuf request");
+  }
+
   private class MetricsEmittingProxyResponseListener<T> extends ProxyResponseListener
   {
     private final HttpServletRequest req;

server/src/test/java/org/apache/druid/server/AsyncQueryForwardingServletTest.java

@@ -468,6 +468,45 @@ public class AsyncQueryForwardingServletTest extends BaseJettyTest
     }
   }
 
+  @Test
+  public void testGetAvaticaProtobufConnectionId()
+  {
+    final String query = "SELECT someColumn FROM druid.someTable WHERE someColumn IS NOT NULL";
+    final String connectionId = "000000-0000-0000-00000000";
+    final int statementId = 1337;
+    final int maxNumRows = 1000;
+
+    final List<? extends Service.Request> avaticaRequests = ImmutableList.of(
+            new Service.CatalogsRequest(connectionId),
+            new Service.SchemasRequest(connectionId, "druid", null),
+            new Service.TablesRequest(connectionId, "druid", "druid", null, null),
+            new Service.ColumnsRequest(connectionId, "druid", "druid", "someTable", null),
+            new Service.PrepareAndExecuteRequest(
+                    connectionId,
+                    statementId,
+                    query,
+                    maxNumRows
+            ),
+            new Service.PrepareRequest(connectionId, query, maxNumRows),
+            new Service.ExecuteRequest(
+                    new Meta.StatementHandle(connectionId, statementId, null),
+                    ImmutableList.of(),
+                    maxNumRows
+            ),
+            new Service.CloseStatementRequest(connectionId, statementId),
+            new Service.CloseConnectionRequest(connectionId)
+    );
+
+
+    for (Service.Request request : avaticaRequests) {
+      Assert.assertEquals(
+              "failed",
+              connectionId,
+              AsyncQueryForwardingServlet.getAvaticaProtobufConnectionId(request)
+      );
+    }
+  }
+
   private static Map<String, Object> asMap(String json, ObjectMapper mapper) throws JsonProcessingException
   {
     return mapper.readValue(json, JacksonUtils.TYPE_REFERENCE_MAP_STRING_OBJECT);

services/src/main/java/org/apache/druid/cli/RouterJettyServerInitializer.java

@@ -39,7 +39,8 @@ import org.apache.druid.server.security.AuthConfig;
 import org.apache.druid.server.security.AuthenticationUtils;
 import org.apache.druid.server.security.Authenticator;
 import org.apache.druid.server.security.AuthenticatorMapper;
-import org.apache.druid.sql.avatica.DruidAvaticaHandler;
+import org.apache.druid.sql.avatica.DruidAvaticaJsonHandler;
+import org.apache.druid.sql.avatica.DruidAvaticaProtobufHandler;
 import org.eclipse.jetty.server.Handler;
 import org.eclipse.jetty.server.Server;
 import org.eclipse.jetty.server.handler.HandlerList;
@@ -57,7 +58,8 @@ public class RouterJettyServerInitializer implements JettyServerInitializer
       // JDBC authentication uses the JDBC connection context instead of HTTP headers, skip the normal auth checks.
       // The router will keep the connection context in the forwarded message, and the broker is responsible for
       // performing the auth checks.
-      DruidAvaticaHandler.AVATICA_PATH
+      DruidAvaticaJsonHandler.AVATICA_PATH,
+      DruidAvaticaProtobufHandler.AVATICA_PATH
   );
 
   private final DruidHttpClientConfig routerHttpClientConfig;

sql/src/main/java/org/apache/druid/sql/avatica/AvaticaModule.java

@@ -36,7 +36,8 @@ public class AvaticaModule implements Module
   {
     JsonConfigProvider.bind(binder, "druid.sql.avatica", AvaticaServerConfig.class);
     binder.bind(AvaticaMonitor.class).in(LazySingleton.class);
-    JettyBindings.addHandler(binder, DruidAvaticaHandler.class);
+    JettyBindings.addHandler(binder, DruidAvaticaJsonHandler.class);
+    JettyBindings.addHandler(binder, DruidAvaticaProtobufHandler.class);
     MetricsModule.register(binder, AvaticaMonitor.class);
   }
 }

sql/src/main/java/org/apache/druid/sql/avatica/DruidAvaticaJsonHandler.java

@@ -32,12 +32,12 @@ import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;
 import java.io.IOException;
 
-public class DruidAvaticaHandler extends AvaticaJsonHandler
+public class DruidAvaticaJsonHandler extends AvaticaJsonHandler
 {
   public static final String AVATICA_PATH = "/druid/v2/sql/avatica/";
 
   @Inject
-  public DruidAvaticaHandler(
+  public DruidAvaticaJsonHandler(
       final DruidMeta druidMeta,
       @Self final DruidNode druidNode,
       final AvaticaMonitor avaticaMonitor

sql/src/main/java/org/apache/druid/sql/avatica/DruidAvaticaProtobufHandler.java

@@ -0,0 +1,62 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.sql.avatica;
+
+import com.google.inject.Inject;
+import org.apache.calcite.avatica.remote.LocalService;
+import org.apache.calcite.avatica.remote.Service;
+import org.apache.calcite.avatica.server.AvaticaProtobufHandler;
+import org.apache.druid.guice.annotations.Self;
+import org.apache.druid.server.DruidNode;
+import org.eclipse.jetty.server.Request;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import java.io.IOException;
+
+public class DruidAvaticaProtobufHandler extends AvaticaProtobufHandler
+{
+  public static final String AVATICA_PATH = "/druid/v2/sql/avatica-protobuf/";
+
+  @Inject
+  public DruidAvaticaProtobufHandler(
+      final DruidMeta druidMeta,
+      @Self final DruidNode druidNode,
+      final AvaticaMonitor avaticaMonitor
+  )
+  {
+    super(new LocalService(druidMeta), avaticaMonitor);
+    setServerRpcMetadata(new Service.RpcMetadataResponse(druidNode.getHostAndPortToUse()));
+  }
+
+  @Override
+  public void handle(
+      final String target,
+      final Request baseRequest,
+      final HttpServletRequest request,
+      final HttpServletResponse response
+  ) throws IOException, ServletException
+  {
+    if (request.getRequestURI().equals(AVATICA_PATH)) {
+      super.handle(target, baseRequest, request, response);
+    }
+  }
+}

sql/src/main/java/org/apache/druid/sql/avatica/DruidMeta.java

@@ -104,9 +104,11 @@ public class DruidMeta extends MetaImpl
   {
     // Build connection context.
     final ImmutableMap.Builder<String, Object> context = ImmutableMap.builder();
+    if (info != null) {
       for (Map.Entry<String, String> entry : info.entrySet()) {
         context.put(entry);
       }
+    }
     openDruidConnection(ch.id, context.build());
   }
 

sql/src/test/java/org/apache/druid/sql/avatica/AvaticaModuleTest.java

@@ -176,19 +176,36 @@ public class AvaticaModuleTest
   }
 
   @Test
-  public void testDruidAvaticaHandlerIsInjected()
+  public void testDruidAvaticaJsonHandlerIsInjected()
   {
-    DruidAvaticaHandler handler = injector.getInstance(DruidAvaticaHandler.class);
+    DruidAvaticaJsonHandler handler = injector.getInstance(DruidAvaticaJsonHandler.class);
     Assert.assertNotNull(handler);
-    DruidAvaticaHandler other = injector.getInstance(DruidAvaticaHandler.class);
+    DruidAvaticaJsonHandler other = injector.getInstance(DruidAvaticaJsonHandler.class);
     Assert.assertNotSame(handler, other);
   }
 
   @Test
-  public void testDruidAvaticaHandlerIsRegisterdWithJerseyModule()
+  public void testDruidAvaticaProtobufHandlerIsInjected()
+  {
+    DruidAvaticaProtobufHandler handler = injector.getInstance(DruidAvaticaProtobufHandler.class);
+    Assert.assertNotNull(handler);
+    DruidAvaticaProtobufHandler other = injector.getInstance(DruidAvaticaProtobufHandler.class);
+    Assert.assertNotSame(handler, other);
+  }
+
+  @Test
+  public void testDruidAvaticaJsonHandlerIsRegisterdWithJerseyModule()
   {
     Set<Handler> handlers =
         injector.getInstance(Key.get(new TypeLiteral<Set<Handler>>(){}));
-    Assert.assertTrue(handlers.stream().anyMatch(h -> DruidAvaticaHandler.class.equals(h.getClass())));
+    Assert.assertTrue(handlers.stream().anyMatch(h -> DruidAvaticaJsonHandler.class.equals(h.getClass())));
+  }
+
+  @Test
+  public void testDruidAvaticaProtobufHandlerIsRegisterdWithJerseyModule()
+  {
+    Set<Handler> handlers =
+            injector.getInstance(Key.get(new TypeLiteral<Set<Handler>>(){}));
+    Assert.assertTrue(handlers.stream().anyMatch(h -> DruidAvaticaProtobufHandler.class.equals(h.getClass())));
   }
 }

sql/src/test/java/org/apache/druid/sql/avatica/DruidAvaticaHandlerTest.java

@@ -35,6 +35,7 @@ import org.apache.calcite.avatica.AvaticaClientRuntimeException;
 import org.apache.calcite.avatica.Meta;
 import org.apache.calcite.avatica.MissingResultsException;
 import org.apache.calcite.avatica.NoSuchStatementException;
+import org.apache.calcite.avatica.server.AbstractAvaticaHandler;
 import org.apache.calcite.schema.SchemaPlus;
 import org.apache.druid.common.config.NullHandling;
 import org.apache.druid.guice.GuiceInjectors;
@@ -46,7 +47,6 @@ import org.apache.druid.java.util.common.io.Closer;
 import org.apache.druid.java.util.emitter.service.ServiceEmitter;
 import org.apache.druid.math.expr.ExprMacroTable;
 import org.apache.druid.query.QueryRunnerFactoryConglomerate;
-import org.apache.druid.server.DruidNode;
 import org.apache.druid.server.QueryLifecycleFactory;
 import org.apache.druid.server.QueryStackTests;
 import org.apache.druid.server.RequestLogLine;
@@ -101,7 +101,7 @@ import java.util.Set;
 import java.util.concurrent.Executors;
 import java.util.concurrent.ThreadLocalRandom;
 
-public class DruidAvaticaHandlerTest extends CalciteTestBase
+public abstract class DruidAvaticaHandlerTest extends CalciteTestBase
 {
   private static final AvaticaServerConfig AVATICA_CONFIG = new AvaticaServerConfig()
   {
@@ -200,20 +200,12 @@ public class DruidAvaticaHandlerTest extends CalciteTestBase
     );
 
     druidMeta = injector.getInstance(DruidMeta.class);
-    final DruidAvaticaHandler handler = new DruidAvaticaHandler(
-        druidMeta,
-        new DruidNode("dummy", "dummy", false, 1, null, true, false),
-        new AvaticaMonitor()
-    );
+    final AbstractAvaticaHandler handler = this.getAvaticaHandler(druidMeta);
     final int port = ThreadLocalRandom.current().nextInt(9999) + 10000;
     server = new Server(new InetSocketAddress("127.0.0.1", port));
     server.setHandler(handler);
     server.start();
-    url = StringUtils.format(
-        "jdbc:avatica:remote:url=http://127.0.0.1:%d%s",
-        port,
-        DruidAvaticaHandler.AVATICA_PATH
-    );
+    url = this.getJdbcConnectionString(port);
     client = DriverManager.getConnection(url, "regularUser", "druid");
     superuserClient = DriverManager.getConnection(url, CalciteTests.TEST_SUPERUSER_NAME, "druid");
 
@@ -886,20 +878,12 @@ public class DruidAvaticaHandlerTest extends CalciteTestBase
       }
     };
 
-    final DruidAvaticaHandler handler = new DruidAvaticaHandler(
-        smallFrameDruidMeta,
-        new DruidNode("dummy", "dummy", false, 1, null, true, false),
-        new AvaticaMonitor()
-    );
+    final AbstractAvaticaHandler handler = this.getAvaticaHandler(smallFrameDruidMeta);
     final int port = ThreadLocalRandom.current().nextInt(9999) + 20000;
     Server smallFrameServer = new Server(new InetSocketAddress("127.0.0.1", port));
     smallFrameServer.setHandler(handler);
     smallFrameServer.start();
-    String smallFrameUrl = StringUtils.format(
-        "jdbc:avatica:remote:url=http://127.0.0.1:%d%s",
-        port,
-        DruidAvaticaHandler.AVATICA_PATH
-    );
+    String smallFrameUrl = this.getJdbcConnectionString(port);
     Connection smallFrameClient = DriverManager.getConnection(smallFrameUrl, "regularUser", "druid");
 
     final ResultSet resultSet = smallFrameClient.createStatement().executeQuery(
@@ -984,20 +968,12 @@ public class DruidAvaticaHandlerTest extends CalciteTestBase
       }
     };
 
-    final DruidAvaticaHandler handler = new DruidAvaticaHandler(
-        smallFrameDruidMeta,
-        new DruidNode("dummy", "dummy", false, 1, null, true, false),
-        new AvaticaMonitor()
-    );
+    final AbstractAvaticaHandler handler = this.getAvaticaHandler(smallFrameDruidMeta);
     final int port = ThreadLocalRandom.current().nextInt(9999) + 20000;
     Server smallFrameServer = new Server(new InetSocketAddress("127.0.0.1", port));
     smallFrameServer.setHandler(handler);
     smallFrameServer.start();
-    String smallFrameUrl = StringUtils.format(
-        "jdbc:avatica:remote:url=http://127.0.0.1:%d%s",
-        port,
-        DruidAvaticaHandler.AVATICA_PATH
-    );
+    String smallFrameUrl = this.getJdbcConnectionString(port);
     Connection smallFrameClient = DriverManager.getConnection(smallFrameUrl, "regularUser", "druid");
 
     // use a prepared statement because avatica currently ignores fetchSize on the initial fetch of a Statement
@@ -1328,6 +1304,10 @@ public class DruidAvaticaHandlerTest extends CalciteTestBase
     );
   }
 
+  protected abstract String getJdbcConnectionString(int port);
+
+  protected abstract AbstractAvaticaHandler getAvaticaHandler(DruidMeta druidMeta);
+
   private static List<Map<String, Object>> getRows(final ResultSet resultSet) throws SQLException
   {
     return getRows(resultSet, null);

sql/src/test/java/org/apache/druid/sql/avatica/DruidAvaticaJsonHandlerTest.java

@@ -0,0 +1,47 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.sql.avatica;
+
+import org.apache.calcite.avatica.server.AbstractAvaticaHandler;
+import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.server.DruidNode;
+
+public class DruidAvaticaJsonHandlerTest extends DruidAvaticaHandlerTest
+{
+  @Override
+  protected String getJdbcConnectionString(final int port)
+  {
+    return StringUtils.format(
+            "jdbc:avatica:remote:url=http://127.0.0.1:%d%s",
+            port,
+            DruidAvaticaJsonHandler.AVATICA_PATH
+    );
+  }
+
+  @Override
+  protected AbstractAvaticaHandler getAvaticaHandler(final DruidMeta druidMeta)
+  {
+    return new DruidAvaticaJsonHandler(
+            druidMeta,
+            new DruidNode("dummy", "dummy", false, 1, null, true, false),
+            new AvaticaMonitor()
+    );
+  }
+}

sql/src/test/java/org/apache/druid/sql/avatica/DruidAvaticaProtobufHandlerTest.java

@@ -0,0 +1,47 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.druid.sql.avatica;
+
+import org.apache.calcite.avatica.server.AbstractAvaticaHandler;
+import org.apache.druid.java.util.common.StringUtils;
+import org.apache.druid.server.DruidNode;
+
+public class DruidAvaticaProtobufHandlerTest extends DruidAvaticaHandlerTest
+{
+  @Override
+  protected String getJdbcConnectionString(final int port)
+  {
+    return StringUtils.format(
+            "jdbc:avatica:remote:url=http://127.0.0.1:%d%s;serialization=protobuf",
+            port,
+            DruidAvaticaProtobufHandler.AVATICA_PATH
+    );
+  }
+
+  @Override
+  protected AbstractAvaticaHandler getAvaticaHandler(final DruidMeta druidMeta)
+  {
+    return new DruidAvaticaProtobufHandler(
+            druidMeta,
+            new DruidNode("dummy", "dummy", false, 1, null, true, false),
+            new AvaticaMonitor()
+    );
+  }
+}

website/.spelling

@@ -1860,3 +1860,5 @@ MiB
 GiB
 TiB
 PiB
+protobuf
+Golang