feat: support query forwards.

databend-client/src/main/java/com/databend/client/ClientSettings.java

@@ -24,6 +24,7 @@ public class ClientSettings {
     public static final int DEFAULT_RETRY_ATTEMPTS = 5;
     public static final String X_Databend_Query_ID = "X-DATABEND-QUERY-ID";
     public static final String X_DATABEND_ROUTE_HINT = "X-DATABEND-ROUTE-HINT";
+    public static final String X_DATABEND_STICKY_NODE = "X-DATABEND-STICKY-NODE";
     public static final String DatabendWarehouseHeader = "X-DATABEND-WAREHOUSE";
     public static final String DatabendTenantHeader = "X-DATABEND-TENANT";
     private final String host;

databend-client/src/main/java/com/databend/client/DatabendClientV1.java

@@ -67,12 +67,13 @@ public class DatabendClientV1
     private final Map<String, String> additonalHeaders;
     // client session
     private final AtomicReference<DatabendSession> databendSession;
+    private String nodeID;
     private final AtomicReference<QueryResults> currentResults = new AtomicReference<>(null);
     private static final Logger logger = Logger.getLogger(DatabendClientV1.class.getPackage().getName());
 
     private Consumer<DatabendSession> on_session_state_update;
 
-    public DatabendClientV1(OkHttpClient httpClient, String sql, ClientSettings settings, Consumer<DatabendSession> on_session_state_update) {
+    public DatabendClientV1(OkHttpClient httpClient, String sql, ClientSettings settings, Consumer<DatabendSession> on_session_state_update, AtomicReference<String> last_node_id) {
         requireNonNull(httpClient, "httpClient is null");
         requireNonNull(sql, "sql is null");
         requireNonNull(settings, "settings is null");
@@ -87,11 +88,13 @@ public DatabendClientV1(OkHttpClient httpClient, String sql, ClientSettings sett
         this.maxRetryAttempts = settings.getRetryAttempts();
         // need atomic reference since it may get updated when query returned.
         this.databendSession = new AtomicReference<>(settings.getSession());
+        this.nodeID = last_node_id.get();
         Request request = buildQueryRequest(query, settings);
         boolean completed = this.execute(request);
         if (!completed) {
             throw new RuntimeException("Query failed to complete");
         }
+        last_node_id.set(this.nodeID);
     }
 
     public static List<DiscoveryNode> discoverNodes(OkHttpClient httpClient, ClientSettings settings) {
@@ -127,8 +130,13 @@ private Request buildQueryRequest(String query, ClientSettings settings) {
         if (reqString == null || reqString.isEmpty()) {
             throw new IllegalArgumentException("Invalid request: " + req);
         }
+
         url = url.newBuilder().encodedPath(QUERY_PATH).build();
         Request.Builder builder = prepareRequest(url, this.additonalHeaders);
+        DatabendSession session = databendSession.get();
+        if (session != null && session.getNeedSticky()) {
+            builder.addHeader(ClientSettings.X_DATABEND_STICKY_NODE, nodeID);
+        }
         return builder.post(okhttp3.RequestBody.create(MEDIA_TYPE_JSON, reqString)).build();
     }
 
@@ -299,6 +307,7 @@ public boolean execute(Request request) {
     }
 
     private void processResponse(Headers headers, QueryResults results) {
+        nodeID = results.getNodeId();
         DatabendSession session = results.getSession();
         if (session != null) {
             databendSession.set(session);
@@ -332,6 +341,7 @@ public boolean advance() {
         HttpUrl url = HttpUrl.get(this.host);
         url = url.newBuilder().encodedPath(nextUriPath).build();
         Request.Builder builder = prepareRequest(url, this.additonalHeaders);
+        builder.addHeader(ClientSettings.X_DATABEND_STICKY_NODE, this.nodeID);
         Request request = builder.get().build();
         return executeInternal(request, OptionalLong.of(MAX_MATERIALIZED_JSON_RESPONSE_SIZE));
     }

databend-client/src/main/java/com/databend/client/DatabendSession.java

@@ -41,22 +41,25 @@ public class DatabendSession {
 
     // txn
     private String txnState;
+    private Boolean needSticky;
 
     private Map<String, Object> additionalProperties = new HashMap<>();
 
     @JsonCreator
     public DatabendSession(
             @JsonProperty("database") String database,
             @JsonProperty("settings") Map<String, String> settings,
-            @JsonProperty("txn_state") String txnState) {
+            @JsonProperty("txn_state") String txnState,
+            @JsonProperty("need_sticky") Boolean needSticky) {
         this.database = database;
         this.settings = settings;
         this.txnState = txnState;
+        this.needSticky = needSticky;
     }
 
     // default
     public static DatabendSession createDefault() {
-        return new DatabendSession(DEFAULT_DATABASE, null, null);
+        return new DatabendSession(DEFAULT_DATABASE, null, null, false);
     }
 
     public static Builder builder() {
@@ -79,6 +82,11 @@ public String getTxnState() {
         return txnState;
     }
 
+    @JsonProperty("need_sticky")
+    public Boolean getNeedSticky() {
+        return needSticky;
+    }
+
     @JsonAnyGetter
     public Map<String, Object> getAdditionalProperties() {
         return additionalProperties;
@@ -145,7 +153,7 @@ public void setAutoCommit(boolean autoCommit) {
         }
 
         public DatabendSession build() {
-            return new DatabendSession(database, settings, txnState);
+            return new DatabendSession(database, settings, txnState, false);
         }
     }
 }

databend-client/src/main/java/com/databend/client/QueryResults.java

@@ -25,6 +25,7 @@
 
 public class QueryResults {
     private final String queryId;
+    private final String nodeId;
     private final String sessionId;
     private final DatabendSession session;
     private final List<QueryRowField> schema;
@@ -42,6 +43,7 @@ public class QueryResults {
     @JsonCreator
     public QueryResults(
             @JsonProperty("id") String queryId,
+            @JsonProperty("node_id") String nodeId,
             @JsonProperty("session_id") String sessionId,
             @JsonProperty("session") DatabendSession session,
             @JsonProperty("schema") List<QueryRowField> schema,
@@ -55,6 +57,7 @@ public QueryResults(
             @JsonProperty("next_uri") URI nextUri,
             @JsonProperty("kill_uri") URI killUri) {
         this.queryId = queryId;
+        this.nodeId = nodeId;
         this.sessionId = sessionId;
         this.session = session;
         this.schema = schema;
@@ -76,6 +79,11 @@ public String getQueryId() {
         return queryId;
     }
 
+    @JsonProperty
+    public String getNodeId() {
+        return nodeId;
+    }
+
     @JsonProperty
     public String getSessionId() {
         return sessionId;

databend-client/src/test/java/com/databend/client/TestClientIT.java

@@ -23,6 +23,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.UUID;
+import java.util.concurrent.atomic.AtomicReference;
 
 import static com.databend.client.ClientSettings.*;
 
@@ -37,7 +38,8 @@ public void testBasicQueryPagination() {
         OkHttpClient client = new OkHttpClient.Builder().addInterceptor(OkHttpUtils.basicAuthInterceptor("databend", "databend")).build();
 
         ClientSettings settings = new ClientSettings(DATABEND_HOST);
-        DatabendClient cli = new DatabendClientV1(client, "select 1", settings, null);
+        AtomicReference<String> lastNodeID = new AtomicReference<>();
+        DatabendClient cli = new DatabendClientV1(client, "select 1", settings, null, lastNodeID);
         System.out.println(cli.getResults().getData());
         Assert.assertEquals(cli.getQuery(), "select 1");
         Assert.assertEquals(cli.getSession().getDatabase(), DATABASE);
@@ -55,8 +57,10 @@ public void testConnectionRefused() {
         OkHttpClient client = new OkHttpClient.Builder().addInterceptor(OkHttpUtils.basicAuthInterceptor("databend", "databend")).build();
         ClientSettings settings = new ClientSettings("http://localhost:13191");
 
+        AtomicReference<String> lastNodeID = new AtomicReference<>();
+
         try {
-            DatabendClient cli = new DatabendClientV1(client, "select 1", settings, null);
+            DatabendClient cli = new DatabendClientV1(client, "select 1", settings, null, lastNodeID);
             cli.getResults(); // This should trigger the connection attempt
             Assert.fail("Expected exception was not thrown");
         } catch (Exception e) {
@@ -71,11 +75,12 @@ public void testConnectionRefused() {
     public void testBasicQueryIDHeader() {
         OkHttpClient client = new OkHttpClient.Builder().addInterceptor(OkHttpUtils.basicAuthInterceptor("databend", "databend")).build();
         String expectedUUID = UUID.randomUUID().toString();
+        AtomicReference<String> lastNodeID = new AtomicReference<>();
 
         Map<String, String> additionalHeaders = new HashMap<>();
         additionalHeaders.put(X_Databend_Query_ID, expectedUUID);
         ClientSettings settings = new ClientSettings(DATABEND_HOST, DatabendSession.createDefault(), DEFAULT_QUERY_TIMEOUT, DEFAULT_CONNECTION_TIMEOUT, DEFAULT_SOCKET_TIMEOUT, PaginationOptions.defaultPaginationOptions(), additionalHeaders, null, DEFAULT_RETRY_ATTEMPTS);
-        DatabendClient cli = new DatabendClientV1(client, "select 1", settings, null);
+        DatabendClient cli = new DatabendClientV1(client, "select 1", settings, null, lastNodeID);
         Assert.assertEquals(cli.getAdditionalHeaders().get(X_Databend_Query_ID), expectedUUID);
 
         String expectedUUID1 = UUID.randomUUID().toString();
@@ -84,7 +89,7 @@ public void testBasicQueryIDHeader() {
         ClientSettings settings1 = new ClientSettings(DATABEND_HOST, DatabendSession.createDefault(), DEFAULT_QUERY_TIMEOUT, DEFAULT_CONNECTION_TIMEOUT, DEFAULT_SOCKET_TIMEOUT, PaginationOptions.defaultPaginationOptions(), additionalHeaders1, null, DEFAULT_RETRY_ATTEMPTS);
         Assert.assertEquals(cli.getAdditionalHeaders().get(X_Databend_Query_ID), expectedUUID);
         // check X_Databend_Query_ID won't change after calling next()
-        DatabendClient cli1 = new DatabendClientV1(client, "SELECT number from numbers(200000) order by number", settings1, null);
+        DatabendClient cli1 = new DatabendClientV1(client, "SELECT number from numbers(200000) order by number", settings1, null, lastNodeID);
         for (int i = 1; i < 1000; i++) {
             cli.advance();
             Assert.assertEquals(cli1.getAdditionalHeaders().get(X_Databend_Query_ID), expectedUUID1);

databend-jdbc/src/main/java/com/databend/jdbc/DatabendConnection.java

@@ -78,6 +78,7 @@ public class DatabendConnection implements Connection, FileTransferAPI, Consumer
     private AtomicReference<DatabendSession> session = new AtomicReference<>();
 
     private String routeHint = "";
+    private AtomicReference<String> lastNodeID = new AtomicReference<>();
 
     private void initializeFileHandler() {
         if (this.debug()) {
@@ -696,12 +697,12 @@ DatabendClient startQueryWithFailover(String sql, StageAttachment attach) throws
                 throw new SQLException("Error start query: " + "SQL: " + sql + " " + e.getMessage() + " cause: " + e.getCause(), e);
             }
             try {
-                // route hint is used when transaction occured or when multi-cluster warehouse adopted(CLOUD ONLY)
+                // route hint is used when transaction occurred or when multi-cluster warehouse adopted(CLOUD ONLY)
                 // on cloud case, we have gateway to handle with route hint, and will not parse URI from route hint.
                 // transaction procedure:
                 // 1. server return session body where txn state is active
-                // 2. when there is a active transaction, it will route all query to target route hint uri if exists
-                // 3. if there is not active transaction, it will use load balancing policy to choose a host to execute query
+                // 2. when there is an active transaction, it will route all query to target route hint uri if exists
+                // 3. if there is not an active transaction, it will use load balancing policy to choose a host to execute query
                 String query_id = UUID.randomUUID().toString();
                 String candidateHost = this.driverUri.getUri(query_id).toString();
                 if (!inActiveTransaction()) {
@@ -726,7 +727,7 @@ DatabendClient startQueryWithFailover(String sql, StageAttachment attach) throws
                 if (this.autoDiscovery) {
                     tryAutoDiscovery(httpClient, s);
                 }
-                return new DatabendClientV1(httpClient, sql, s, this);
+                return new DatabendClientV1(httpClient, sql, s, this, lastNodeID);
             } catch (RuntimeException e1) {
                 e = e1;
             } catch (Exception e1) {