HBASE-27332 Remove RejectedExecutionHandler for long/short compaction…

… thread pools (#4731)

Signed-off-by: Duo Zhang <zhangduo@apache.org>

hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/CompactSplit.java

@@ -31,7 +31,6 @@
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.Executors;
 import java.util.concurrent.RejectedExecutionException;
-import java.util.concurrent.RejectedExecutionHandler;
 import java.util.concurrent.ThreadPoolExecutor;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicInteger;
@@ -145,15 +144,18 @@ private void createCompactionExecutors() {
     final String n = Thread.currentThread().getName();
 
     StealJobQueue<Runnable> stealJobQueue = new StealJobQueue<Runnable>(COMPARATOR);
+    // Since the StealJobQueue inner uses the PriorityBlockingQueue,
+    // which is an unbounded blocking queue, we remove the RejectedExecutionHandler for
+    // the long and short compaction thread pool executors since HBASE-27332.
+    // If anyone who what to change the StealJobQueue to a bounded queue,
+    // please add the rejection handler back.
     this.longCompactions = new ThreadPoolExecutor(largeThreads, largeThreads, 60, TimeUnit.SECONDS,
       stealJobQueue,
       new ThreadFactoryBuilder().setNameFormat(n + "-longCompactions-%d").setDaemon(true).build());
-    this.longCompactions.setRejectedExecutionHandler(new Rejection());
     this.longCompactions.prestartAllCoreThreads();
     this.shortCompactions = new ThreadPoolExecutor(smallThreads, smallThreads, 60, TimeUnit.SECONDS,
       stealJobQueue.getStealFromQueue(),
       new ThreadFactoryBuilder().setNameFormat(n + "-shortCompactions-%d").setDaemon(true).build());
-    this.shortCompactions.setRejectedExecutionHandler(new Rejection());
   }
 
   @Override
@@ -724,22 +726,6 @@ private String formatStackTrace(Exception ex) {
     }
   }
 
-  /**
-   * Cleanup class to use when rejecting a compaction request from the queue.
-   */
-  private static class Rejection implements RejectedExecutionHandler {
-    @Override
-    public void rejectedExecution(Runnable runnable, ThreadPoolExecutor pool) {
-      if (runnable instanceof CompactionRunner) {
-        CompactionRunner runner = (CompactionRunner) runnable;
-        LOG.debug("Compaction Rejected: " + runner);
-        if (runner.compaction != null) {
-          runner.store.cancelRequestedCompaction(runner.compaction);
-        }
-      }
-    }
-  }
-
   /**
    * {@inheritDoc}
    */