Solves issue-2191 (#2337)

Author: mzitnik

client-v2/src/main/java/com/clickhouse/client/api/Client.java

@@ -192,16 +192,24 @@ private Client(Set<String> endpoints, Map<String,String> configuration, boolean
      *
      */
     public void loadServerInfo() {
-        try (QueryResponse response = this.query("SELECT currentUser() AS user, timezone() AS timezone, version() AS version LIMIT 1").get()) {
-            try (ClickHouseBinaryFormatReader reader = this.newBinaryFormatReader(response)) {
-                if (reader.next() != null) {
-                    this.configuration.put(ClientConfigProperties.USER.getKey(), reader.getString("user"));
-                    this.configuration.put(ClientConfigProperties.SERVER_TIMEZONE.getKey(), reader.getString("timezone"));
-                    serverVersion = reader.getString("version");
+        // only if 2 properties are set disable retrieval from server
+        if (!this.configuration.containsKey(ClientConfigProperties.SERVER_TIMEZONE.getKey()) && !this.configuration.containsKey(ClientConfigProperties.SERVER_VERSION.getKey())) {
+            try (QueryResponse response = this.query("SELECT currentUser() AS user, timezone() AS timezone, version() AS version LIMIT 1").get()) {
+                try (ClickHouseBinaryFormatReader reader = this.newBinaryFormatReader(response)) {
+                    if (reader.next() != null) {
+                        this.configuration.put(ClientConfigProperties.USER.getKey(), reader.getString("user"));
+                        this.configuration.put(ClientConfigProperties.SERVER_TIMEZONE.getKey(), reader.getString("timezone"));
+                        serverVersion = reader.getString("version");
+                    }
                 }
+            } catch (Exception e) {
+                throw new ClientException("Failed to get server info", e);
+            }
+        } else {
+            LOG.info("Using server version " + this.configuration.get(ClientConfigProperties.SERVER_VERSION.getKey()) + " and timezone " + this.configuration.get(ClientConfigProperties.SERVER_TIMEZONE.getKey()) );
+            if (this.configuration.containsKey(ClientConfigProperties.SERVER_VERSION.getKey())) {
+                serverVersion = this.configuration.get(ClientConfigProperties.SERVER_VERSION.getKey());
             }
-        } catch (Exception e) {
-            throw new ClientException("Failed to get server info", e);
         }
     }
 
@@ -991,6 +999,17 @@ public Builder registerClientMetrics(Object registry, String name) {
             return this;
         }
 
+        /**
+         * Sets server version that the client is interacting with.
+         *
+         * @param serverVersion - ClickHouse server version
+         * @return same instance of the builder
+         */
+        public Builder setServerVersion(String serverVersion) {
+            this.configuration.put(ClientConfigProperties.SERVER_VERSION.getKey(), serverVersion);
+            return this;
+        }
+
         public Client build() {
             setDefaults();
 
@@ -2174,6 +2193,10 @@ public String getServerVersion() {
         return this.serverVersion;
     }
 
+    public String getServerTimeZone() {
+        return this.configuration.get(ClientConfigProperties.SERVER_TIMEZONE.getKey());
+    }
+
     public String getClientVersion() {
         return clientVersion;
     }

client-v2/src/main/java/com/clickhouse/client/api/ClientConfigProperties.java

@@ -36,6 +36,8 @@ public enum ClientConfigProperties {
 
     USE_TIMEZONE("use_time_zone"),
 
+    SERVER_VERSION("server_version"),
+
     SERVER_TIMEZONE("server_time_zone"),
 
     ASYNC_OPERATIONS("async"),

jdbc-v2/src/test/java/com/clickhouse/jdbc/ConnectionTest.java

@@ -2,12 +2,9 @@
 
 import java.nio.charset.StandardCharsets;
 import java.sql.*;
-import java.util.Arrays;
-import java.util.Base64;
-import java.util.Properties;
+import java.util.*;
 
 import java.util.Properties;
-import java.util.UUID;
 
 import com.clickhouse.client.ClickHouseNode;
 import com.clickhouse.client.ClickHouseProtocol;
@@ -553,5 +550,21 @@ public void testJWTWithCloud() throws Exception {
              Assert.assertTrue(rs.next());
         }
     }
+    @Test(groups = { "integration" })
+    public void testDisableExtraCallToServer() throws Exception {
+        Properties properties = new Properties();
+        properties.put(ClientConfigProperties.SERVER_TIMEZONE.getKey(), "GMT");
+        properties.put(ClientConfigProperties.SERVER_VERSION.getKey(), "1.0.0");
+        try (Connection conn = getJdbcConnection(properties);
+             Statement stmt = conn.createStatement();
+             ResultSet rs = stmt.executeQuery("SELECT 1")) {
+             Assert.assertTrue(rs.next());
+             ConnectionImpl connImpl = (ConnectionImpl) conn;
+
+             Assert.assertEquals(connImpl.getClient().getServerVersion(), "1.0.0");
+             Assert.assertEquals(connImpl.getClient().getServerTimeZone(), "GMT");
+        }
+
+    }
 
 }