redesign TaskTracker's lock solutions

oh-my-scheduler-worker/src/main/java/com/github/kfcfans/oms/worker/core/tracker/task/TaskTracker.java

@@ -35,6 +35,7 @@ import java.util.Optional;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.concurrent.atomic.AtomicInteger;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * 负责管理 JobInstance 的运行，主要包括任务的派发（MR可能存在大量的任务）和状态的更新
@@ -61,6 +62,11 @@ public abstract class TaskTracker {
     protected AtomicBoolean finished;
     // 上报时间缓存
     private Cache<String, Long> taskId2LastReportTime;
+    // 分段锁
+    private ReentrantLock[] locks = new ReentrantLock[UPDATE_CONCURRENCY];
+
+    private static final int UPDATE_CONCURRENCY = 8;
+    private static final int UPDATE_LOCK_MASK = UPDATE_CONCURRENCY - 1;
 
     protected TaskTracker(ServerScheduleJobReq req) {
 
@@ -84,6 +90,11 @@ public abstract class TaskTracker {
         // 构建缓存
         taskId2LastReportTime = CacheBuilder.newBuilder().maximumSize(1024).build();
 
+        // 构建分段锁
+        for (int i = 0; i < UPDATE_CONCURRENCY; i++) {
+            locks[i] = new ReentrantLock();
+        }
+
         // 子类自定义初始化操作
         initTaskTracker(req);
 
@@ -107,6 +118,7 @@ public abstract class TaskTracker {
     /* *************************** 对外方法区 *************************** */
     /**
      * 更新Task状态
+     * V1.0.0 -> V1.0.1 锁方案变更，从 synchronized (taskId.intern()) 修改为分段锁，能大大减少内存占用，损失的只有理论并发度而已
      * @param taskId task的ID（task为任务实例的执行单位）
      * @param newStatus task的新状态
      * @param reportTime 上报时间
@@ -114,12 +126,13 @@ public abstract class TaskTracker {
      */
     public void updateTaskStatus(String taskId, int newStatus, long reportTime, @Nullable String result) {
 
-        TaskStatus nTaskStatus = TaskStatus.of(newStatus);
+        ReentrantLock lock = locks[taskId.hashCode() & UPDATE_LOCK_MASK];
 
-        // 同一个task，串行执行
-        // 需要保证 worker 的其他代码没有用 taskId 或者 String 作为锁...否则就等着找bug吧...（主要是不舍得加前缀，这用的可以常量池内存啊...）
-        // taskId其实是可能重复的（同一台机器上多个 TaskTracker...不过真实冲突概率较低，就算冲突了也问题不大，忽略）
-        synchronized (taskId.intern()) {
+        TaskStatus nTaskStatus = TaskStatus.of(newStatus);
+        try {
+
+            // 阻塞获取锁
+            lock.lock();
 
             Long lastReportTime = taskId2LastReportTime.getIfPresent(taskId);
 
@@ -129,7 +142,7 @@ public abstract class TaskTracker {
                 if (taskOpt.isPresent()) {
                     lastReportTime = taskOpt.get().getLastReportTime();
                 }else {
-                    // 理论上不存在这种情况
+                    // 理论上不存在这种情况，除非数据库异常
                     log.error("[TaskTracker-{}] can't find task by pkey(instanceId={}&taskId={}).", instanceId, instanceId, taskId);
                 }
 
@@ -193,6 +206,9 @@ public abstract class TaskTracker {
             if (!updateResult) {
                 log.warn("[TaskTracker-{}] update task status failed, this task(taskId={}) may be processed repeatedly!", instanceId, taskId);
             }
+
+        }finally {
+            lock.unlock();
         }
     }
 

oh-my-scheduler-worker/src/main/java/com/github/kfcfans/oms/worker/persistence/TaskPersistenceService.java

@@ -28,7 +28,7 @@ public class TaskPersistenceService {
 
     // 默认重试参数
     private static final int RETRY_TIMES = 3;
-    private static final long RETRY_INTERVAL_MS = 200;
+    private static final long RETRY_INTERVAL_MS = 100;
 
     private static volatile boolean initialized = false;
     public static TaskPersistenceService INSTANCE = new TaskPersistenceService();