HBASE-22072 High read/write intensive regions may cause long crash (#214)

* HBASE-22072 High read/write intensive regions may cause long crash
recovery

* Make the 'closing' variable as volatile and move the test case to
standlone class

Author: ramkrish86

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

@@ -79,8 +79,7 @@ public class StoreScanner extends NonReversedNonLazyKeyValueScanner
   private int storeOffset = 0;
 
   // Used to indicate that the scanner has closed (see HBASE-1107)
-  // Do not need to be volatile because it's always accessed via synchronized methods
-  private boolean closing = false;
+  private volatile boolean closing = false;
   private final boolean get;
   private final boolean explicitColumnQuery;
   private final boolean useRowColBloom;
@@ -157,6 +156,8 @@ public class StoreScanner extends NonReversedNonLazyKeyValueScanner
   final List<KeyValueScanner> currentScanners = new ArrayList<>();
   // flush update lock
   private final ReentrantLock flushLock = new ReentrantLock();
+  // lock for closing.
+  private final ReentrantLock closeLock = new ReentrantLock();
 
   protected final long readPt;
   private boolean topChanged = false;
@@ -473,31 +474,38 @@ public void close() {
   }
 
   private void close(boolean withDelayedScannersClose) {
-    if (this.closing) {
-      return;
-    }
-    if (withDelayedScannersClose) {
-      this.closing = true;
-    }
-    // For mob compaction, we do not have a store.
-    if (this.store != null) {
-      this.store.deleteChangedReaderObserver(this);
-    }
-    if (withDelayedScannersClose) {
-      clearAndClose(scannersForDelayedClose);
-      clearAndClose(memStoreScannersAfterFlush);
-      clearAndClose(flushedstoreFileScanners);
-      if (this.heap != null) {
-        this.heap.close();
-        this.currentScanners.clear();
-        this.heap = null; // CLOSED!
+    closeLock.lock();
+    // If the closeLock is acquired then any subsequent updateReaders()
+    // call is ignored.
+    try {
+      if (this.closing) {
+        return;
       }
-    } else {
-      if (this.heap != null) {
-        this.scannersForDelayedClose.add(this.heap);
-        this.currentScanners.clear();
-        this.heap = null;
+      if (withDelayedScannersClose) {
+        this.closing = true;
+      }
+      // For mob compaction, we do not have a store.
+      if (this.store != null) {
+        this.store.deleteChangedReaderObserver(this);
       }
+      if (withDelayedScannersClose) {
+        clearAndClose(scannersForDelayedClose);
+        clearAndClose(memStoreScannersAfterFlush);
+        clearAndClose(flushedstoreFileScanners);
+        if (this.heap != null) {
+          this.heap.close();
+          this.currentScanners.clear();
+          this.heap = null; // CLOSED!
+        }
+      } else {
+        if (this.heap != null) {
+          this.scannersForDelayedClose.add(this.heap);
+          this.currentScanners.clear();
+          this.heap = null;
+        }
+      }
+    } finally {
+      closeLock.unlock();
     }
   }
 
@@ -876,8 +884,25 @@ public void updateReaders(List<HStoreFile> sfs, List<KeyValueScanner> memStoreSc
     if (CollectionUtils.isEmpty(sfs) && CollectionUtils.isEmpty(memStoreScanners)) {
       return;
     }
+    boolean updateReaders = false;
     flushLock.lock();
     try {
+      if (!closeLock.tryLock()) {
+        // The reason for doing this is that when the current store scanner does not retrieve
+        // any new cells, then the scanner is considered to be done. The heap of this scanner
+        // is not closed till the shipped() call is completed. Hence in that case if at all
+        // the partial close (close (false)) has been called before updateReaders(), there is no
+        // need for the updateReaders() to happen.
+        LOG.debug("StoreScanner already has the close lock. There is no need to updateReaders");
+        // no lock acquired.
+        return;
+      }
+      // lock acquired
+      updateReaders = true;
+      if (this.closing) {
+        LOG.debug("StoreScanner already closing. There is no need to updateReaders");
+        return;
+      }
       flushed = true;
       final boolean isCompaction = false;
       boolean usePread = get || scanUsePread;
@@ -896,6 +921,9 @@ public void updateReaders(List<HStoreFile> sfs, List<KeyValueScanner> memStoreSc
       }
     } finally {
       flushLock.unlock();
+      if (updateReaders) {
+        closeLock.unlock();
+      }
     }
     // Let the next() call handle re-creating and seeking
   }

hbase-server/src/test/java/org/apache/hadoop/hbase/regionserver/TestStoreScanner.java

@@ -34,12 +34,14 @@
 import java.util.OptionalInt;
 import java.util.TreeSet;
 import java.util.concurrent.atomic.AtomicInteger;
+
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellComparator;
 import org.apache.hadoop.hbase.CellUtil;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.HBaseConfiguration;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.KeepDeletedCells;
 import org.apache.hadoop.hbase.KeyValue;
@@ -74,6 +76,7 @@ public class TestStoreScanner {
   private static final String CF_STR = "cf";
   private static final byte[] CF = Bytes.toBytes(CF_STR);
   static Configuration CONF = HBaseConfiguration.create();
+  private static final HBaseTestingUtility TEST_UTIL = new HBaseTestingUtility();
   private ScanInfo scanInfo = new ScanInfo(CONF, CF, 0, Integer.MAX_VALUE, Long.MAX_VALUE,
       KeepDeletedCells.FALSE, HConstants.DEFAULT_BLOCKSIZE, 0, CellComparator.getInstance(), false);
 
@@ -847,7 +850,6 @@ public void testScannerReseekDoesntNPE() throws Exception {
     }
   }
 
-
   @Test @Ignore("this fails, since we don't handle deletions, etc, in peek")
   public void testPeek() throws Exception {
     KeyValue[] kvs = new KeyValue [] {