isolate broken graphd server while client application is running

client/src/main/java/com/vesoft/nebula/client/graph/SessionPool.java

@@ -55,6 +55,7 @@ public class SessionPool implements Serializable {
     private final int healthCheckTime;
     private final int retryTimes;
     private final int intervalTime;
+    private final boolean reconnect;
     private final String spaceName;
     private final String useSpace;
 
@@ -66,6 +67,7 @@ public SessionPool(SessionPoolConfig poolConfig) {
         this.cleanTime = poolConfig.getCleanTime();
         this.retryTimes = poolConfig.getRetryTimes();
         this.intervalTime = poolConfig.getIntervalTime();
+        this.reconnect = poolConfig.isReconnect();
         this.healthCheckTime = poolConfig.getHealthCheckTime();
         this.spaceName = poolConfig.getSpaceName();
         useSpace = "USE `" + spaceName + "`;";
@@ -146,7 +148,7 @@ public ResultSet execute(String stmt) throws IOErrorException,
         NebulaSession nebulaSession = null;
         ResultSet resultSet = null;
         int tryTimes = 0;
-        while (tryTimes++ < retryTimes) {
+        while (tryTimes++ <= retryTimes) {
             try {
                 nebulaSession = getSession();
                 resultSet = nebulaSession.execute(stmt);
@@ -160,6 +162,11 @@ public ResultSet execute(String stmt) throws IOErrorException,
                         resultSet.getErrorCode(), resultSet.getErrorMessage(), tryTimes));
                 nebulaSession.release();
                 sessionList.remove(nebulaSession);
+                try {
+                    Thread.sleep(intervalTime);
+                } catch (InterruptedException interruptedException) {
+                    // ignore
+                }
             } catch (ClientServerIncompatibleException e) {
                 // will never get here.
             } catch (AuthFailedException | BindSpaceFailedException e) {
@@ -330,11 +337,25 @@ private void updateSessionQueue() {
      * @param state {@link SessionState}
      * @return NebulaSession
      */
-    private synchronized NebulaSession createSessionObject(SessionState state)
+    private NebulaSession createSessionObject(SessionState state)
             throws ClientServerIncompatibleException, AuthFailedException,
             IOErrorException, BindSpaceFailedException {
         SyncConnection connection = new SyncConnection();
-        connection.open(getAddress(), sessionPoolConfig.getTimeout());
+        int tryConnect = sessionPoolConfig.getGraphAddressList().size();
+        // reconnect with all available address
+        while (tryConnect-- > 0) {
+            try {
+                connection.open(getAddress(), sessionPoolConfig.getTimeout());
+                break;
+            } catch (Exception e) {
+                if (tryConnect == 0 || !reconnect) {
+                    throw e;
+                } else {
+                    log.warn("connect failed, " + e.getMessage());
+                }
+            }
+        }
+
         AuthResult authResult;
         try {
             authResult = connection.authenticate(sessionPoolConfig.getUsername(),

client/src/main/java/com/vesoft/nebula/client/graph/SessionPoolConfig.java

@@ -44,6 +44,9 @@ public class SessionPoolConfig implements Serializable {
     // interval time for retry, unit ms
     private int intervalTime = 0;
 
+    // whether reconnect when create session using a broken graphd server
+    private boolean reconnect = false;
+
 
     public SessionPoolConfig(List<HostAddress> addresses,
                              String spaceName,
@@ -180,6 +183,14 @@ public SessionPoolConfig setIntervalTime(int intervalTime) {
         return this;
     }
 
+    public boolean isReconnect() {
+        return reconnect;
+    }
+
+    public SessionPoolConfig setReconnect(boolean reconnect) {
+        this.reconnect = reconnect;
+        return this;
+    }
 
     @Override
     public String toString() {
@@ -195,6 +206,7 @@ public String toString() {
                 + ", waitTime=" + waitTime
                 + ", retryTimes=" + retryTimes
                 + ", intervalTIme=" + intervalTime
+                + ", reconnect=" + reconnect
                 + '}';
     }
 }