HBASE-5081 Distributed log splitting deleteNode races againsth splitLog retry; REAPPLY

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1222045 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -477,6 +477,8 @@ Release 0.92.0 - Unreleased
    HBASE-4868  TestOfflineMetaRebuildBase#testMetaRebuild occasionally fails
                (Gao Jinchao)
    HBASE-4874  Run tests with non-secure random, some tests hang otherwise (Lars H)
+   HBASE-5081  Distributed log splitting deleteNode races againsth
+               splitLog retry (Jimmy Xiang)
 
   IMPROVEMENTS
    HBASE-3290  Max Compaction Size (Nicolas Spiegelberg via Stack)  

src/main/java/org/apache/hadoop/hbase/master/SplitLogManager.java

@@ -332,6 +332,7 @@ public class SplitLogManager extends ZooKeeperListener {
         LOG.warn("Error splitting " + path);
       }
     }
+    boolean safeToDeleteNodeAsync = true;
     Task task = tasks.get(path);
     if (task == null) {
       if (!ZKSplitLog.isRescanNode(watcher, path)) {
@@ -345,6 +346,13 @@ public class SplitLogManager extends ZooKeeperListener {
         // forgetting about them then we will have to handle the race when
         // accessing task.batch here.
         if (!task.isOrphan()) {
+          if (status != SUCCESS) {
+            // If the task is failed, deleting the node asynchronously
+            // will cause race issue against split log retry.
+            // In this case, we should delete it now.
+            safeToDeleteNodeAsync = false;
+            deleteNodeNow(path);
+          }
           synchronized (task.batch) {
             if (status == SUCCESS) {
               task.batch.done++;
@@ -359,11 +367,35 @@ public class SplitLogManager extends ZooKeeperListener {
     // delete the task node in zk. Keep trying indefinitely - its an async
     // call and no one is blocked waiting for this node to be deleted. All
     // task names are unique (log.<timestamp>) there is no risk of deleting
-    // a future task.
-    deleteNode(path, Long.MAX_VALUE);
+    // a future task.  This is true if the task status is SUCCESS, otherwise,
+    // it may race against split log retry.
+    if (safeToDeleteNodeAsync) {
+      deleteNode(path, Long.MAX_VALUE);
+    }
     return;
   }
 
+  private void deleteNodeNow(String path) {
+    try {
+      tot_mgr_node_delete_queued.incrementAndGet();
+      this.watcher.getRecoverableZooKeeper().delete(path, -1);
+      tot_mgr_task_deleted.incrementAndGet();
+    } catch (KeeperException ke) {
+      if (ke.code() != KeeperException.Code.NONODE) {
+        tot_mgr_node_delete_err.incrementAndGet();
+        LOG.warn("Failed to delete failed task node: "
+          + path + " due to " + ke.getMessage());
+      } else {
+        LOG.info("Failed task node does not exist, "
+            + "either was never created or was already deleted: " + path);
+        tot_mgr_task_deleted.incrementAndGet();
+      }
+    } catch (InterruptedException ie) {
+      LOG.warn("Interrupted while waiting for failed task node to be deleted");
+      Thread.currentThread().interrupt();
+    }
+  }
+
   private void createNode(String path, Long retry_count) {
     ZKUtil.asyncCreate(this.watcher, path,
         TaskState.TASK_UNASSIGNED.get(serverName), new CreateAsyncCallback(),

src/test/java/org/apache/hadoop/hbase/master/TestSplitLogManager.java

@@ -328,6 +328,28 @@ public class TestSplitLogManager {
     }
     waitForCounter(tot_mgr_task_deleted, 0, 1, 1000);
     assertTrue(ZKUtil.checkExists(zkw, tasknode) == -1);
+
+    conf.setInt("hbase.splitlog.max.resubmit", 0);
+    slm.stopTrackingTasks(batch);
+    batch = new TaskBatch();
+    resetCounters();
+
+    // inject a failed task node, and retry
+    ZKUtil.createAndWatch(zkw, tasknode, TaskState.TASK_ERR.get("worker"));
+
+    slm.enqueueSplitTask("foo/1", batch);
+    assertEquals(1, batch.installed);
+    assertTrue(slm.findOrCreateOrphanTask(tasknode).batch == batch);
+    waitForCounter(tot_mgr_node_already_exists, 0, 1, 1000);
+
+    synchronized (batch) {
+      while (batch.installed != batch.error) {
+        batch.wait();
+      }
+    }
+    waitForCounter(tot_mgr_task_deleted, 0, 1, 1000);
+    assertTrue(ZKUtil.checkExists(zkw, tasknode) == -1);
+
     conf.setInt("hbase.splitlog.max.resubmit", ZKSplitLog.DEFAULT_MAX_RESUBMIT);
   }