From 866e3090393fe4a091364f4889af69ed0643b527 Mon Sep 17 00:00:00 2001
From: dongeforever <dongeforever@apache.org>
Date: Tue, 20 Nov 2018 15:06:46 +0800
Subject: [PATCH] Make role change handler asynchronous

---
 .../dleger/DLegerRoleChangeHandler.java       | 74 +++++++++++++------
 1 file changed, 50 insertions(+), 24 deletions(-)

diff --git a/broker/src/main/java/org/apache/rocketmq/broker/dleger/DLegerRoleChangeHandler.java b/broker/src/main/java/org/apache/rocketmq/broker/dleger/DLegerRoleChangeHandler.java
index 67498964..e1d8e7e9 100644
--- a/broker/src/main/java/org/apache/rocketmq/broker/dleger/DLegerRoleChangeHandler.java
+++ b/broker/src/main/java/org/apache/rocketmq/broker/dleger/DLegerRoleChangeHandler.java
@@ -16,9 +16,13 @@
  */
 package org.apache.rocketmq.broker.dleger;
 
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
 import org.apache.rocketmq.broker.BrokerController;
+import org.apache.rocketmq.common.ThreadFactoryImpl;
 import org.apache.rocketmq.common.constant.LoggerName;
 import org.apache.rocketmq.dleger.DLegerLeaderElector;
+import org.apache.rocketmq.dleger.DLegerServer;
 import org.apache.rocketmq.dleger.MemberState;
 import org.apache.rocketmq.dleger.utils.UtilAll;
 import org.apache.rocketmq.logging.InternalLogger;
@@ -30,41 +34,63 @@ import org.apache.rocketmq.store.dleger.DLegerCommitLog;
 public class DLegerRoleChangeHandler implements DLegerLeaderElector.RoleChangeHandler {
 
     private static final InternalLogger log = InternalLoggerFactory.getLogger(LoggerName.BROKER_LOGGER_NAME);
+    private ExecutorService executorService = Executors.newSingleThreadExecutor(new ThreadFactoryImpl("DLegerRoleChangeHandler_"));
     private BrokerController brokerController;
     private DefaultMessageStore messageStore;
     private DLegerCommitLog dLegerCommitLog;
+    private DLegerServer dLegerServer;
     public DLegerRoleChangeHandler(BrokerController brokerController, DefaultMessageStore messageStore) {
         this.brokerController = brokerController;
         this.messageStore = messageStore;
         this.dLegerCommitLog = (DLegerCommitLog) messageStore.getCommitLog();
+        this.dLegerServer = dLegerCommitLog.getdLegerServer();
     }
 
     @Override public void handle(long term, MemberState.Role role) {
-        long start = System.currentTimeMillis();
-        try {
-            log.info("Begin handling broker role change term={} role={} currStoreRole={}", term, role, messageStore.getMessageStoreConfig().getBrokerRole());
-            switch (role) {
-                case CANDIDATE:
-                    if (messageStore.getMessageStoreConfig().getBrokerRole() != BrokerRole.SLAVE) {
-                        brokerController.changeToSlave(dLegerCommitLog.getId());
+        Runnable runnable = new Runnable() {
+            @Override public void run() {
+                long start = System.currentTimeMillis();
+                try {
+                    log.info("Begin handling broker role change term={} role={} currStoreRole={}", term, role, messageStore.getMessageStoreConfig().getBrokerRole());
+                    switch (role) {
+                        case CANDIDATE:
+                            if (messageStore.getMessageStoreConfig().getBrokerRole() != BrokerRole.SLAVE) {
+                                brokerController.changeToSlave(dLegerCommitLog.getId());
+                            }
+                            break;
+                        case FOLLOWER:
+                            brokerController.changeToSlave(dLegerCommitLog.getId());
+                            break;
+                        case LEADER:
+                            while (dLegerServer.getMemberState().isLeader()
+                                &&  (dLegerServer.getdLegerStore().getLegerEndIndex() != dLegerServer.getdLegerStore().getCommittedIndex() ||  messageStore.dispatchBehindBytes() != 0)) {
+                                UtilAll.sleep(100);
+                            }
+                            boolean succ = dLegerServer.getMemberState().isLeader()
+                                && dLegerServer.getdLegerStore().getLegerEndIndex() == dLegerServer.getdLegerStore().getCommittedIndex()
+                                && messageStore.dispatchBehindBytes() == 0;
+                            if (succ) {
+                                messageStore.recoverTopicQueueTable();
+                                brokerController.changeToMaster(BrokerRole.SYNC_MASTER);
+                            }
+                            log.info("Finish handling broker role change succ={} term={} role={} currStoreRole={} cost={}", succ, term, role, messageStore.getMessageStoreConfig().getBrokerRole(), UtilAll.elapsed(start));
+                            break;
+                        default:
+                            break;
                     }
-                    break;
-                case FOLLOWER:
-                    brokerController.changeToSlave(dLegerCommitLog.getId());
-                    break;
-                case LEADER:
-                    while (messageStore.dispatchBehindBytes() != 0) {
-                        Thread.sleep(100);
-                    }
-                    messageStore.recoverTopicQueueTable();
-                    brokerController.changeToMaster(BrokerRole.SYNC_MASTER);
-                    break;
-                default:
-                    break;
+                } catch (Throwable t) {
+                    log.info("[MONITOR]Failed handling broker role change term={} role={} currStoreRole={} cost={}", term, role, messageStore.getMessageStoreConfig().getBrokerRole(), UtilAll.elapsed(start), t);
+                }
             }
-            log.info("Finish handling broker role change term={} role={} currStoreRole={} cost={}", term, role, messageStore.getMessageStoreConfig().getBrokerRole(), UtilAll.elapsed(start));
-        } catch (Throwable t) {
-            log.info("[MONITOR]Failed handling broker role change term={} role={} currStoreRole={} cost={}", term, role, messageStore.getMessageStoreConfig().getBrokerRole(), UtilAll.elapsed(start), t);
-        }
+        };
+        executorService.submit(runnable);
+    }
+
+    @Override public void startup() {
+
+    }
+
+    @Override public void shutdown() {
+        executorService.shutdown();
     }
 }
-- 
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