HBASE-22463 Some paths in HFileScannerImpl did not consider block#release which will exhaust the ByteBuffAllocator (#257)

hbase-external-blockcache/src/main/java/org/apache/hadoop/hbase/io/hfile/MemcachedBlockCache.java

@@ -37,7 +37,6 @@ import net.spy.memcached.transcoders.Transcoder;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.io.ByteBuffAllocator;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.nio.ByteBuff;
 import org.apache.hadoop.hbase.nio.SingleByteBuff;
 import org.apache.hadoop.hbase.trace.TraceUtil;
@@ -272,8 +271,7 @@ public class MemcachedBlockCache implements BlockCache {
     public HFileBlock decode(CachedData d) {
       try {
         ByteBuff buf = new SingleByteBuff(ByteBuffer.wrap(d.getData()));
-        return (HFileBlock) HFileBlock.BLOCK_DESERIALIZER.deserialize(buf, ByteBuffAllocator.HEAP,
+        return (HFileBlock) HFileBlock.BLOCK_DESERIALIZER.deserialize(buf, ByteBuffAllocator.HEAP);
-          MemoryType.EXCLUSIVE);
       } catch (IOException e) {
         LOG.warn("Failed to deserialize data from memcached", e);
       }

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/Cacheable.java

@@ -63,20 +63,6 @@ public interface Cacheable extends HeapSize, HBaseReferenceCounted {
    */
   BlockType getBlockType();
 
-  /**
-   * @return the {@code MemoryType} of this Cacheable
-   */
-  MemoryType getMemoryType();
-
-  /**
-   * SHARED means when this Cacheable is read back from cache it refers to the same memory area as
-   * used by the cache for caching it. EXCLUSIVE means when this Cacheable is read back from cache,
-   * the data was copied to an exclusive memory area of this Cacheable.
-   */
-  enum MemoryType {
-    SHARED, EXCLUSIVE
-  }
-
   /******************************* ReferenceCounted Interfaces ***********************************/
 
   /**

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/CacheableDeserializer.java

@@ -20,9 +20,8 @@ package org.apache.hadoop.hbase.io.hfile;
 import java.io.IOException;
 
 import org.apache.hadoop.hbase.io.ByteBuffAllocator;
-import org.apache.yetus.audience.InterfaceAudience;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.nio.ByteBuff;
+import org.apache.yetus.audience.InterfaceAudience;
 
 /**
  * Interface for a deserializer. Throws an IOException if the serialized data is incomplete or
@@ -33,11 +32,10 @@ public interface CacheableDeserializer<T extends Cacheable> {
   /**
    * @param b ByteBuff to deserialize the Cacheable.
    * @param allocator to manage NIO ByteBuffers for future allocation or de-allocation.
-   * @param memType the {@link MemoryType} of the buffer
    * @return T the deserialized object.
    * @throws IOException
    */
-  T deserialize(ByteBuff b, ByteBuffAllocator allocator, MemoryType memType) throws IOException;
+  T deserialize(ByteBuff b, ByteBuffAllocator allocator) throws IOException;
 
   /**
    * Get the identifier of this deserializer. Identifier is unique for each deserializer and

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileBlock.java

@@ -201,8 +201,6 @@ public class HFileBlock implements Cacheable {
    */
   private long offset = UNSET;
 
-  private MemoryType memType = MemoryType.EXCLUSIVE;
-
   /**
    * The on-disk size of the next block, including the header and checksums if present.
    * UNSET if unknown.
@@ -274,7 +272,7 @@ public class HFileBlock implements Cacheable {
     }
 
     @Override
-    public HFileBlock deserialize(ByteBuff buf, ByteBuffAllocator alloc, MemoryType memType)
+    public HFileBlock deserialize(ByteBuff buf, ByteBuffAllocator alloc)
         throws IOException {
       // The buf has the file block followed by block metadata.
       // Set limit to just before the BLOCK_METADATA_SPACE then rewind.
@@ -287,8 +285,7 @@ public class HFileBlock implements Cacheable {
       boolean usesChecksum = buf.get() == (byte) 1;
       long offset = buf.getLong();
       int nextBlockOnDiskSize = buf.getInt();
-      return new HFileBlock(newByteBuff, usesChecksum, memType, offset, nextBlockOnDiskSize, null,
+      return new HFileBlock(newByteBuff, usesChecksum, offset, nextBlockOnDiskSize, null, alloc);
-          alloc);
     }
 
     @Override
@@ -366,7 +363,7 @@ public class HFileBlock implements Cacheable {
    * to that point.
    * @param buf Has header, content, and trailing checksums if present.
    */
-  HFileBlock(ByteBuff buf, boolean usesHBaseChecksum, MemoryType memType, final long offset,
+  HFileBlock(ByteBuff buf, boolean usesHBaseChecksum, final long offset,
       final int nextBlockOnDiskSize, HFileContext fileContext, ByteBuffAllocator allocator)
       throws IOException {
     buf.rewind();
@@ -398,7 +395,6 @@ public class HFileBlock implements Cacheable {
     assert usesHBaseChecksum == fileContext.isUseHBaseChecksum();
     init(blockType, onDiskSizeWithoutHeader, uncompressedSizeWithoutHeader, prevBlockOffset, offset,
       onDiskDataSizeWithHeader, nextBlockOnDiskSize, fileContext, allocator);
-    this.memType = memType;
     this.offset = offset;
     this.buf = buf;
     this.buf.rewind();
@@ -1785,8 +1781,8 @@ public class HFileBlock implements Cacheable {
         // The onDiskBlock will become the headerAndDataBuffer for this block.
         // If nextBlockOnDiskSizeWithHeader is not zero, the onDiskBlock already
         // contains the header of next block, so no need to set next block's header in it.
-        HFileBlock hFileBlock = new HFileBlock(curBlock, checksumSupport, MemoryType.EXCLUSIVE,
+        HFileBlock hFileBlock = new HFileBlock(curBlock, checksumSupport, offset,
-            offset, nextBlockOnDiskSize, fileContext, intoHeap ? HEAP: allocator);
+            nextBlockOnDiskSize, fileContext, intoHeap ? HEAP : allocator);
         // Run check on uncompressed sizings.
         if (!fileContext.isCompressedOrEncrypted()) {
           hFileBlock.sanityCheckUncompressed();
@@ -2060,18 +2056,6 @@ public class HFileBlock implements Cacheable {
     return this.fileContext;
   }
 
-  @Override
-  public MemoryType getMemoryType() {
-    return this.memType;
-  }
-
-  /**
-   * @return true if this block is backed by a shared memory area(such as that of a BucketCache).
-   */
-  boolean usesSharedMemory() {
-    return this.memType == MemoryType.SHARED;
-  }
-
   /**
    * Convert the contents of the block header into a human readable string.
    * This is mostly helpful for debugging. This assumes that the block

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/HFileReaderImpl.java

@@ -24,8 +24,6 @@ import java.security.Key;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
-import java.util.concurrent.atomic.AtomicBoolean;
-import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.hadoop.conf.Configurable;
 import org.apache.hadoop.conf.Configuration;
@@ -489,8 +487,6 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
     private int currValueLen;
     private int currMemstoreTSLen;
     private long currMemstoreTS;
-    // Updated but never read?
-    protected AtomicInteger blockFetches = new AtomicInteger(0);
     protected final HFile.Reader reader;
     private int currTagsLen;
     // buffer backed keyonlyKV
@@ -506,7 +502,11 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
      * If the nextIndexedKey is null, it means the nextIndexedKey has not been loaded yet.
      */
     protected Cell nextIndexedKey;
-    // Current block being used
+    // Current block being used. NOTICE: DON't release curBlock separately except in shipped() or
+    // close() methods. Because the shipped() or close() will do the release finally, even if any
+    // exception occur the curBlock will be released by the close() method (see
+    // RegionScannerImpl#handleException). Call the releaseIfNotCurBlock() to release the
+    // unreferenced block please.
     protected HFileBlock curBlock;
     // Previous blocks that were used in the course of the read
     protected final ArrayList<HFileBlock> prevBlocks = new ArrayList<>();
@@ -520,12 +520,10 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
     }
 
     void updateCurrBlockRef(HFileBlock block) {
-      if (block != null && this.curBlock != null &&
+      if (block != null && curBlock != null && block.getOffset() == curBlock.getOffset()) {
-          block.getOffset() == this.curBlock.getOffset()) {
         return;
       }
-      // We don't have to keep ref to EXCLUSIVE type of block
+      if (this.curBlock != null) {
-      if (this.curBlock != null && this.curBlock.usesSharedMemory()) {
         prevBlocks.add(this.curBlock);
       }
       this.curBlock = block;
@@ -533,7 +531,7 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
 
     void reset() {
       // We don't have to keep ref to EXCLUSIVE type of block
-      if (this.curBlock != null && this.curBlock.usesSharedMemory()) {
+      if (this.curBlock != null) {
         this.prevBlocks.add(this.curBlock);
       }
       this.curBlock = null;
@@ -821,7 +819,6 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
             return loadBlockAndSeekToKey(this.curBlock, nextIndexedKey, false, key,
                 false);
           }
-
         }
       }
       // Don't rewind on a reseek operation, because reseek implies that we are
@@ -848,8 +845,7 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
       BlockWithScanInfo blockWithScanInfo = indexReader.loadDataBlockWithScanInfo(key, curBlock,
         cacheBlocks, pread, isCompaction, getEffectiveDataBlockEncoding());
       if (blockWithScanInfo == null || blockWithScanInfo.getHFileBlock() == null) {
-        // This happens if the key e.g. falls before the beginning of the
+        // This happens if the key e.g. falls before the beginning of the file.
-        // file.
         return -1;
       }
       return loadBlockAndSeekToKey(blockWithScanInfo.getHFileBlock(),
@@ -869,22 +865,22 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
         // The key we are interested in
         if (previousBlockOffset == -1) {
           // we have a 'problem', the key we want is the first of the file.
+          releaseIfNotCurBlock(seekToBlock);
           return false;
         }
 
         // The first key in the current block 'seekToBlock' is greater than the given
         // seekBefore key. We will go ahead by reading the next block that satisfies the
         // given key. Return the current block before reading the next one.
-        seekToBlock.release();
+        releaseIfNotCurBlock(seekToBlock);
         // It is important that we compute and pass onDiskSize to the block
         // reader so that it does not have to read the header separately to
         // figure out the size. Currently, we do not have a way to do this
         // correctly in the general case however.
         // TODO: See https://issues.apache.org/jira/browse/HBASE-14576
         int prevBlockSize = -1;
-        seekToBlock = reader.readBlock(previousBlockOffset,
+        seekToBlock = reader.readBlock(previousBlockOffset, prevBlockSize, cacheBlocks, pread,
-            prevBlockSize, cacheBlocks,
+          isCompaction, true, BlockType.DATA, getEffectiveDataBlockEncoding());
-            pread, isCompaction, true, BlockType.DATA, getEffectiveDataBlockEncoding());
         // TODO shortcut: seek forward in this block to the last key of the
         // block.
       }
@@ -892,6 +888,16 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
       return true;
     }
 
+    /**
+     * The curBlock will be released by shipping or close method, so only need to consider releasing
+     * the block, which was read from HFile before and not referenced by curBlock.
+     */
+    protected void releaseIfNotCurBlock(HFileBlock block) {
+      if (curBlock != block) {
+        block.release();
+      }
+    }
+
     /**
      * Scans blocks in the "scanned" section of the {@link HFile} until the next
      * data block is found.
@@ -903,33 +909,30 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
         justification="Yeah, unnecessary null check; could do w/ clean up")
     protected HFileBlock readNextDataBlock() throws IOException {
       long lastDataBlockOffset = reader.getTrailer().getLastDataBlockOffset();
-      if (curBlock == null)
+      if (curBlock == null) {
         return null;
-
+      }
       HFileBlock block = this.curBlock;
-
       do {
         if (block.getOffset() >= lastDataBlockOffset) {
+          releaseIfNotCurBlock(block);
           return null;
         }
-
         if (block.getOffset() < 0) {
-          throw new IOException(
+          releaseIfNotCurBlock(block);
-              "Invalid block file offset: " + block + ", path=" + reader.getPath());
+          throw new IOException("Invalid block file offset: " + block + ", path=" + reader.getPath());
         }
-
         // We are reading the next block without block type validation, because
         // it might turn out to be a non-data block.
         block = reader.readBlock(block.getOffset() + block.getOnDiskSizeWithHeader(),
-            block.getNextBlockOnDiskSize(), cacheBlocks, pread,
+          block.getNextBlockOnDiskSize(), cacheBlocks, pread, isCompaction, true, null,
-            isCompaction, true, null, getEffectiveDataBlockEncoding());
+          getEffectiveDataBlockEncoding());
-        if (block != null && !block.getBlockType().isData()) { // Findbugs: NP_NULL_ON_SOME_PATH
+        if (block != null && !block.getBlockType().isData()) {
           // Whatever block we read we will be returning it unless
           // it is a datablock. Just in case the blocks are non data blocks
           block.release();
         }
       } while (!block.getBlockType().isData());
-
       return block;
     }
 
@@ -1109,8 +1112,7 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
       }
 
       long firstDataBlockOffset = reader.getTrailer().getFirstDataBlockOffset();
-      if (curBlock != null
+      if (curBlock != null && curBlock.getOffset() == firstDataBlockOffset) {
-          && curBlock.getOffset() == firstDataBlockOffset) {
         return processFirstDataBlock();
       }
 
@@ -1128,8 +1130,8 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
       HFileBlock newBlock = reader.readBlock(firstDataBlockOffset, -1, cacheBlocks, pread,
         isCompaction, true, BlockType.DATA, getEffectiveDataBlockEncoding());
       if (newBlock.getOffset() < 0) {
-        throw new IOException(
+        releaseIfNotCurBlock(newBlock);
-            "Invalid block offset: " + newBlock.getOffset() + ", path=" + reader.getPath());
+        throw new IOException("Invalid block offset: " + newBlock.getOffset() + ", path=" + reader.getPath());
       }
       updateCurrentBlock(newBlock);
     }
@@ -1176,26 +1178,26 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
     }
 
     /**
-     * Updates the current block to be the given {@link HFileBlock}. Seeks to
+     * Updates the current block to be the given {@link HFileBlock}. Seeks to the the first
-     * the the first key/value pair.
+     * key/value pair.
-     *
+     * @param newBlock the block read by {@link HFileReaderImpl#readBlock}, it's a totally new block
-     * @param newBlock the block to make current
+     *          with new allocated {@link ByteBuff}, so if no further reference to this block, we
+     *          should release it carefully.
      */
     protected void updateCurrentBlock(HFileBlock newBlock) throws IOException {
-      // Set the active block on the reader
+      try {
-      // sanity check
         if (newBlock.getBlockType() != BlockType.DATA) {
-        throw new IllegalStateException("ScannerV2 works only on data " + "blocks, got "
+          throw new IllegalStateException(
-            + newBlock.getBlockType() + "; " + "HFileName=" + reader.getPath()
+              "ScannerV2 works only on data blocks, got " + newBlock.getBlockType() + "; "
-            + ", " + "dataBlockEncoder=" + reader.getDataBlockEncoding() + ", " + "isCompaction="
+                  + "HFileName=" + reader.getPath() + ", " + "dataBlockEncoder="
-            + isCompaction);
+                  + reader.getDataBlockEncoding() + ", " + "isCompaction=" + isCompaction);
         }
-
         updateCurrBlockRef(newBlock);
         blockBuffer = newBlock.getBufferWithoutHeader();
         readKeyValueLen();
-      blockFetches.incrementAndGet();
+      } finally {
-
+        releaseIfNotCurBlock(newBlock);
+      }
       // Reset the next indexed key
       this.nextIndexedKey = null;
     }
@@ -1643,15 +1645,16 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
     }
 
     /**
-     * Updates the current block to be the given {@link HFileBlock}. Seeks to
+     * Updates the current block to be the given {@link HFileBlock}. Seeks to the the first
-     * the the first key/value pair.
+     * key/value pair.
-     *
+     * @param newBlock the block to make current, and read by {@link HFileReaderImpl#readBlock},
-     * @param newBlock the block to make current
+     *          it's a totally new block with new allocated {@link ByteBuff}, so if no further
+     *          reference to this block, we should release it carefully.
      * @throws CorruptHFileException
      */
     @Override
     protected void updateCurrentBlock(HFileBlock newBlock) throws CorruptHFileException {
-
+      try {
         // sanity checks
         if (newBlock.getBlockType() != BlockType.ENCODED_DATA) {
           throw new IllegalStateException("EncodedScanner works only on encoded data blocks");
@@ -1659,16 +1662,16 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
         short dataBlockEncoderId = newBlock.getDataBlockEncodingId();
         if (!DataBlockEncoding.isCorrectEncoder(dataBlockEncoder, dataBlockEncoderId)) {
           String encoderCls = dataBlockEncoder.getClass().getName();
-        throw new CorruptHFileException("Encoder " + encoderCls
+          throw new CorruptHFileException(
-          + " doesn't support data block encoding "
+              "Encoder " + encoderCls + " doesn't support data block encoding "
-          + DataBlockEncoding.getNameFromId(dataBlockEncoderId)
+                  + DataBlockEncoding.getNameFromId(dataBlockEncoderId) + ",path=" + reader.getPath());
-          + ", path=" + reader.getPath());
         }
         updateCurrBlockRef(newBlock);
         ByteBuff encodedBuffer = getEncodedBuffer(newBlock);
         seeker.setCurrentBuffer(encodedBuffer);
-      blockFetches.incrementAndGet();
+      } finally {
-
+        releaseIfNotCurBlock(newBlock);
+      }
       // Reset the next indexed key
       this.nextIndexedKey = null;
     }
@@ -1748,8 +1751,7 @@ public class HFileReaderImpl implements HFile.Reader, Configurable {
     @Override
     protected int loadBlockAndSeekToKey(HFileBlock seekToBlock, Cell nextIndexedKey,
         boolean rewind, Cell key, boolean seekBefore) throws IOException {
-      if (this.curBlock == null
+      if (this.curBlock == null || this.curBlock.getOffset() != seekToBlock.getOffset()) {
-          || this.curBlock.getOffset() != seekToBlock.getOffset()) {
         updateCurrentBlock(seekToBlock);
       } else if (rewind) {
         seeker.rewind();

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/LruBlockCache.java

@@ -530,16 +530,9 @@ public class LruBlockCache implements FirstLevelBlockCache {
       if (victimHandler != null && !repeat) {
         // The handler will increase result's refCnt for RPC, so need no extra retain.
         Cacheable result = victimHandler.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
-
         // Promote this to L1.
         if (result != null) {
           if (caching) {
-            if (result instanceof HFileBlock && ((HFileBlock) result).usesSharedMemory()) {
-              Cacheable original = result;
-              result = ((HFileBlock) original).deepCloneOnHeap();
-              // deepClone an new one, so need to release the original one to deallocate it.
-              original.release();
-            }
             cacheBlock(cacheKey, result, /* inMemory = */ false);
           }
         }

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/TinyLfuBlockCache.java

@@ -171,8 +171,8 @@ public final class TinyLfuBlockCache implements FirstLevelBlockCache {
       if (victimCache != null) {
         value = victimCache.getBlock(cacheKey, caching, repeat, updateCacheMetrics);
         if ((value != null) && caching) {
-          if ((value instanceof HFileBlock) && ((HFileBlock) value).usesSharedMemory()) {
+          if ((value instanceof HFileBlock) && !((HFileBlock) value).isOnHeap()) {
-            value = ((HFileBlock) value).deepClone();
+            value = ((HFileBlock) value).deepCloneOnHeap();
           }
           cacheBlock(cacheKey, value);
         }
@@ -248,17 +248,6 @@ public final class TinyLfuBlockCache implements FirstLevelBlockCache {
         .iterator();
   }
 
-  @Override
-  public void returnBlock(BlockCacheKey cacheKey, Cacheable block) {
-    // There is no SHARED type here in L1. But the block might have been served from the L2 victim
-    // cache (when the Combined mode = false). So just try return this block to the victim cache.
-    // Note : In case of CombinedBlockCache we will have this victim cache configured for L1
-    // cache. But CombinedBlockCache will only call returnBlock on L2 cache.
-    if (victimCache != null) {
-      victimCache.returnBlock(cacheKey, block);
-    }
-  }
-
   private void logStats() {
     LOG.info(
         "totalSize=" + StringUtils.byteDesc(heapSize()) + ", " +

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/BucketEntry.java

@@ -29,7 +29,6 @@ import java.util.concurrent.locks.ReentrantReadWriteLock;
 import org.apache.hadoop.hbase.io.ByteBuffAllocator;
 import org.apache.hadoop.hbase.io.hfile.BlockPriority;
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.io.hfile.CacheableDeserializer;
 import org.apache.hadoop.hbase.io.hfile.CacheableDeserializerIdManager;
 import org.apache.hadoop.hbase.nio.ByteBuff;
@@ -194,9 +193,9 @@ class BucketEntry implements HBaseReferenceCounted {
     return this.refCnt() > 1 || (evicted && refCnt() == 1);
   }
 
-  Cacheable wrapAsCacheable(ByteBuffer[] buffers, MemoryType memoryType) throws IOException {
+  Cacheable wrapAsCacheable(ByteBuffer[] buffers) throws IOException {
     ByteBuff buf = ByteBuff.wrap(buffers, this.refCnt);
-    return this.deserializerReference().deserialize(buf, allocator, memoryType);
+    return this.deserializerReference().deserialize(buf, allocator);
   }
 
   interface BucketEntryHandler<T> {

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/ByteBufferIOEngine.java

@@ -23,7 +23,6 @@ import java.nio.ByteBuffer;
 
 import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.nio.ByteBuff;
 import org.apache.hadoop.hbase.util.ByteBufferAllocator;
 import org.apache.hadoop.hbase.util.ByteBufferArray;
@@ -104,10 +103,9 @@ public class ByteBufferIOEngine implements IOEngine {
     // Here the buffer that is created directly refers to the buffer in the actual buckets.
     // When any cell is referring to the blocks created out of these buckets then it means that
     // those cells are referring to a shared memory area which if evicted by the BucketCache would
-    // lead to corruption of results. Hence we set the type of the buffer as SHARED_MEMORY
+    // lead to corruption of results. The readers using this block are aware of this fact and do the
-    // so that the readers using this block are aware of this fact and do the necessary action
+    // necessary action to prevent eviction till the results are either consumed or copied
-    // to prevent eviction till the results are either consumed or copied
+    return be.wrapAsCacheable(buffers);
-    return be.wrapAsCacheable(buffers, MemoryType.SHARED);
   }
 
   /**

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/ExclusiveMemoryMmapIOEngine.java

@@ -20,7 +20,6 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.nio.ByteBuff;
 import org.apache.yetus.audience.InterfaceAudience;
 
@@ -39,6 +38,6 @@ public class ExclusiveMemoryMmapIOEngine extends FileMmapIOEngine {
     ByteBuff dst = ByteBuff.wrap(ByteBuffer.allocate(be.getLength()));
     bufferArray.read(be.offset(), dst);
     dst.position(0).limit(be.getLength());
-    return be.wrapAsCacheable(dst.nioByteBuffers(), MemoryType.EXCLUSIVE);
+    return be.wrapAsCacheable(dst.nioByteBuffers());
   }
 }

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/FileIOEngine.java

@@ -30,7 +30,6 @@ import java.util.concurrent.locks.ReentrantLock;
 
 import org.apache.hadoop.hbase.exceptions.IllegalArgumentIOException;
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.nio.ByteBuff;
 import org.apache.hadoop.util.StringUtils;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -143,7 +142,7 @@ public class FileIOEngine implements IOEngine {
       }
     }
     dstBuffer.rewind();
-    return be.wrapAsCacheable(new ByteBuffer[] { dstBuffer }, MemoryType.EXCLUSIVE);
+    return be.wrapAsCacheable(new ByteBuffer[] { dstBuffer });
   }
 
   @VisibleForTesting

hbase-server/src/main/java/org/apache/hadoop/hbase/io/hfile/bucket/SharedMemoryMmapIOEngine.java

@@ -21,7 +21,6 @@ import java.io.IOException;
 import java.nio.ByteBuffer;
 
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.yetus.audience.InterfaceAudience;
 
 /**
@@ -54,9 +53,8 @@ public class SharedMemoryMmapIOEngine extends FileMmapIOEngine {
     // Here the buffer that is created directly refers to the buffer in the actual buckets.
     // When any cell is referring to the blocks created out of these buckets then it means that
     // those cells are referring to a shared memory area which if evicted by the BucketCache would
-    // lead to corruption of results. Hence we set the type of the buffer as SHARED_MEMORY
+    // lead to corruption of results. The readers using this block are aware of this fact and do
-    // so that the readers using this block are aware of this fact and do the necessary action
+    // the necessary action to prevent eviction till the results are either consumed or copied
-    // to prevent eviction till the results are either consumed or copied
+    return be.wrapAsCacheable(buffers);
-    return be.wrapAsCacheable(buffers, MemoryType.SHARED);
   }
 }

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/CacheTestUtils.java

@@ -232,8 +232,7 @@ public class CacheTestUtils {
           }
 
           @Override
-          public Cacheable deserialize(ByteBuff b, ByteBuffAllocator alloc, MemoryType memType)
+          public Cacheable deserialize(ByteBuff b, ByteBuffAllocator alloc) throws IOException {
-              throws IOException {
             int len = b.getInt();
             Thread.yield();
             byte buf[] = new byte[len];
@@ -281,11 +280,6 @@ public class CacheTestUtils {
     public BlockType getBlockType() {
       return BlockType.DATA;
     }
-
-    @Override
-    public MemoryType getMemoryType() {
-      return MemoryType.EXCLUSIVE;
-    }
   }
 
 

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestCacheConfig.java

@@ -36,7 +36,6 @@ import org.apache.hadoop.hbase.HColumnDescriptor;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.io.ByteBuffAllocator;
 import org.apache.hadoop.hbase.io.hfile.BlockType.BlockCategory;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.io.hfile.bucket.BucketCache;
 import org.apache.hadoop.hbase.io.util.MemorySizeUtil;
 import org.apache.hadoop.hbase.nio.ByteBuff;
@@ -82,7 +81,7 @@ public class TestCacheConfig {
     }
 
     @Override
-    public Cacheable deserialize(ByteBuff b, ByteBuffAllocator alloc, MemoryType memType)
+    public Cacheable deserialize(ByteBuff b, ByteBuffAllocator alloc)
         throws IOException {
       LOG.info("Deserialized " + b);
       return cacheable;
@@ -144,11 +143,6 @@ public class TestCacheConfig {
     public BlockType getBlockType() {
       return BlockType.DATA;
     }
-
-    @Override
-    public MemoryType getMemoryType() {
-      return MemoryType.EXCLUSIVE;
-    }
   }
 
   static class MetaCacheEntry extends DataCacheEntry {

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestCachedBlockQueue.java

@@ -145,11 +145,6 @@ public class TestCachedBlockQueue extends TestCase {
               return BlockType.DATA;
             }
 
-            @Override
-            public MemoryType getMemoryType() {
-              return MemoryType.EXCLUSIVE;
-            }
-
           }, accessTime, false);
     }
   }

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileBlock.java

@@ -61,7 +61,6 @@ import org.apache.hadoop.hbase.io.ByteBuffAllocator;
 import org.apache.hadoop.hbase.io.compress.Compression;
 import org.apache.hadoop.hbase.io.compress.Compression.Algorithm;
 import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.nio.ByteBuff;
 import org.apache.hadoop.hbase.nio.MultiByteBuff;
 import org.apache.hadoop.hbase.nio.SingleByteBuff;
@@ -526,7 +525,7 @@ public class TestHFileBlock {
               ByteBuffer serialized = ByteBuffer.allocate(blockFromHFile.getSerializedLength());
               blockFromHFile.serialize(serialized, true);
               HFileBlock deserialized = (HFileBlock) blockFromHFile.getDeserializer()
-                  .deserialize(new SingleByteBuff(serialized), HEAP, MemoryType.EXCLUSIVE);
+                  .deserialize(new SingleByteBuff(serialized), HEAP);
               assertEquals("Serialization did not preserve block state. reuseBuffer=" + reuseBuffer,
                 blockFromHFile, deserialized);
               // intentional reference comparison

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestHFileScannerImplReferenceCount.java

@@ -0,0 +1,301 @@
+/**
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.io.hfile;
+
+import static org.apache.hadoop.hbase.io.hfile.HFileBlockIndex.MAX_CHUNK_SIZE_KEY;
+import static org.apache.hadoop.hbase.io.hfile.HFileBlockIndex.MIN_INDEX_NUM_ENTRIES_KEY;
+import static org.junit.Assert.assertEquals;
+
+import java.io.IOException;
+import java.util.Random;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.Cell;
+import org.apache.hadoop.hbase.CellComparatorImpl;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseTestingUtility;
+import org.apache.hadoop.hbase.HConstants;
+import org.apache.hadoop.hbase.KeyValue;
+import org.apache.hadoop.hbase.io.compress.Compression.Algorithm;
+import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
+import org.apache.hadoop.hbase.io.hfile.HFileReaderImpl.HFileScannerImpl;
+import org.apache.hadoop.hbase.testclassification.IOTests;
+import org.apache.hadoop.hbase.testclassification.SmallTests;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+@Category({ IOTests.class, SmallTests.class })
+public class TestHFileScannerImplReferenceCount {
+
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+      HBaseClassTestRule.forClass(TestHFileScannerImplReferenceCount.class);
+
+  private static final Logger LOG =
+      LoggerFactory.getLogger(TestHFileScannerImplReferenceCount.class);
+  private static final HBaseTestingUtility UTIL = new HBaseTestingUtility();
+  private static final byte[] FAMILY = Bytes.toBytes("f");
+  private static final byte[] QUALIFIER = Bytes.toBytes("q");
+  private static final byte[] SUFFIX = randLongBytes();
+
+  private static byte[] randLongBytes() {
+    Random rand = new Random();
+    byte[] keys = new byte[300];
+    rand.nextBytes(keys);
+    return keys;
+  }
+
+  private Cell firstCell = null;
+  private Cell secondCell = null;
+
+  @BeforeClass
+  public static void setUp() {
+    Configuration conf = UTIL.getConfiguration();
+    // Set the max chunk size and min entries key to be very small for index block, so that we can
+    // create an index block tree with level >= 2.
+    conf.setInt(MAX_CHUNK_SIZE_KEY, 10);
+    conf.setInt(MIN_INDEX_NUM_ENTRIES_KEY, 2);
+  }
+
+  private void writeHFile(Configuration conf, FileSystem fs, Path hfilePath, Algorithm compression,
+      DataBlockEncoding encoding, int cellCount) throws IOException {
+    HFileContext context =
+        new HFileContextBuilder().withBlockSize(1).withDataBlockEncoding(DataBlockEncoding.NONE)
+            .withCompression(compression).withDataBlockEncoding(encoding).build();
+    try (HFile.Writer writer =
+        new HFile.WriterFactory(conf, new CacheConfig(conf)).withPath(fs, hfilePath)
+            .withFileContext(context).withComparator(CellComparatorImpl.COMPARATOR).create()) {
+      Random rand = new Random(9713312); // Just a fixed seed.
+      for (int i = 0; i < cellCount; ++i) {
+        byte[] keyBytes = Bytes.add(Bytes.toBytes(i), SUFFIX);
+
+        // A random-length random value.
+        byte[] valueBytes = RandomKeyValueUtil.randomValue(rand);
+        KeyValue keyValue =
+            new KeyValue(keyBytes, FAMILY, QUALIFIER, HConstants.LATEST_TIMESTAMP, valueBytes);
+        if (firstCell == null) {
+          firstCell = keyValue;
+        } else if (secondCell == null) {
+          secondCell = keyValue;
+        }
+        writer.append(keyValue);
+      }
+    }
+  }
+
+  private void testReleaseBlock(Algorithm compression, DataBlockEncoding encoding)
+      throws Exception {
+    Configuration conf = new Configuration(UTIL.getConfiguration());
+    Path dir = UTIL.getDataTestDir("testReleasingBlock");
+    FileSystem fs = dir.getFileSystem(conf);
+    try {
+      String hfileName = "testReleaseBlock_hfile_0_" + System.currentTimeMillis();
+      Path hfilePath = new Path(dir, hfileName);
+      int cellCount = 1000;
+      LOG.info("Start to write {} cells into hfile: {}", cellCount, hfilePath);
+      writeHFile(conf, fs, hfilePath, compression, encoding, cellCount);
+
+      BlockCache defaultBC = BlockCacheFactory.createBlockCache(conf);
+      Assert.assertNotNull(defaultBC);
+      HFile.Reader reader =
+          HFile.createReader(fs, hfilePath, new CacheConfig(conf, defaultBC), true, conf);
+      Assert.assertTrue(reader instanceof HFileReaderImpl);
+      // We've build a HFile tree with index = 16.
+      Assert.assertEquals(16, reader.getTrailer().getNumDataIndexLevels());
+
+      HFileScanner scanner = reader.getScanner(true, true, false);
+      BlockWithScanInfo scanInfo = reader.getDataBlockIndexReader()
+          .loadDataBlockWithScanInfo(firstCell, null, true, true, false, DataBlockEncoding.NONE);
+      BlockWithScanInfo scanInfo2 = reader.getDataBlockIndexReader()
+          .loadDataBlockWithScanInfo(secondCell, null, true, true, false, DataBlockEncoding.NONE);
+      HFileBlock block = scanInfo.getHFileBlock();
+      HFileBlock block2 = scanInfo2.getHFileBlock();
+      // One refCnt for blockCache and the other refCnt for RPC path.
+      Assert.assertEquals(block.refCnt(), 2);
+      Assert.assertEquals(block2.refCnt(), 2);
+      Assert.assertFalse(block == block2);
+
+      scanner.seekTo(firstCell);
+      Assert.assertEquals(block.refCnt(), 3);
+
+      // Seek to the block again, the curBlock won't change and won't read from BlockCache. so
+      // refCnt should be unchanged.
+      scanner.seekTo(firstCell);
+      Assert.assertEquals(block.refCnt(), 3);
+
+      scanner.seekTo(secondCell);
+      Assert.assertEquals(block.refCnt(), 3);
+      Assert.assertEquals(block2.refCnt(), 3);
+
+      // After shipped, the block will be release, but block2 is still referenced by the curBlock.
+      scanner.shipped();
+      Assert.assertEquals(block.refCnt(), 2);
+      Assert.assertEquals(block2.refCnt(), 3);
+
+      // Try to ship again, though with nothing to client.
+      scanner.shipped();
+      Assert.assertEquals(block.refCnt(), 2);
+      Assert.assertEquals(block2.refCnt(), 3);
+
+      // The curBlock(block2) will also be released.
+      scanner.close();
+      Assert.assertEquals(block2.refCnt(), 2);
+
+      // Finish the block & block2 RPC path
+      block.release();
+      block2.release();
+      Assert.assertEquals(block.refCnt(), 1);
+      Assert.assertEquals(block2.refCnt(), 1);
+
+      // Evict the LRUBlockCache
+      Assert.assertTrue(defaultBC.evictBlocksByHfileName(hfileName) >= 2);
+      Assert.assertEquals(block.refCnt(), 0);
+      Assert.assertEquals(block2.refCnt(), 0);
+
+      int count = 0;
+      Assert.assertTrue(scanner.seekTo());
+      ++count;
+      while (scanner.next()) {
+        count++;
+      }
+      assertEquals(cellCount, count);
+    } finally {
+      fs.delete(dir, true);
+    }
+  }
+
+  /**
+   * See HBASE-22480
+   */
+  @Test
+  public void testSeekBefore() throws IOException {
+    Configuration conf = new Configuration(UTIL.getConfiguration());
+    Path dir = UTIL.getDataTestDir("testSeekBefore");
+    FileSystem fs = dir.getFileSystem(conf);
+    try {
+      String hfileName = "testSeekBefore_hfile_0_" + System.currentTimeMillis();
+      Path hfilePath = new Path(dir, hfileName);
+      int cellCount = 1000;
+      LOG.info("Start to write {} cells into hfile: {}", cellCount, hfilePath);
+      writeHFile(conf, fs, hfilePath, Algorithm.NONE, DataBlockEncoding.NONE, cellCount);
+
+      BlockCache defaultBC = BlockCacheFactory.createBlockCache(conf);
+      Assert.assertNotNull(defaultBC);
+      HFile.Reader reader =
+          HFile.createReader(fs, hfilePath, new CacheConfig(conf, defaultBC), true, conf);
+      Assert.assertTrue(reader instanceof HFileReaderImpl);
+      // We've build a HFile tree with index = 16.
+      Assert.assertEquals(16, reader.getTrailer().getNumDataIndexLevels());
+
+      HFileScanner scanner = reader.getScanner(true, true, false);
+      HFileBlock block1 = reader.getDataBlockIndexReader()
+          .loadDataBlockWithScanInfo(firstCell, null, true, true, false, DataBlockEncoding.NONE)
+          .getHFileBlock();
+      HFileBlock block2 = reader.getDataBlockIndexReader()
+          .loadDataBlockWithScanInfo(secondCell, null, true, true, false, DataBlockEncoding.NONE)
+          .getHFileBlock();
+      Assert.assertEquals(block1.refCnt(), 2);
+      Assert.assertEquals(block2.refCnt(), 2);
+
+      // Let the curBlock refer to block2.
+      scanner.seekTo(secondCell);
+      Assert.assertTrue(((HFileScannerImpl) scanner).curBlock == block2);
+      Assert.assertEquals(3, block2.refCnt());
+
+      // Release the block1, only one reference: blockCache.
+      Assert.assertFalse(block1.release());
+      Assert.assertEquals(1, block1.refCnt());
+      // Release the block2, so the remain references are: 1. scanner; 2. blockCache.
+      Assert.assertFalse(block2.release());
+      Assert.assertEquals(2, block2.refCnt());
+
+      // Do the seekBefore: the newBlock will be the previous block of curBlock.
+      Assert.assertTrue(scanner.seekBefore(secondCell));
+      Assert.assertTrue(((HFileScannerImpl) scanner).curBlock == block1);
+      // Two reference for block1: 1. scanner; 2. blockCache.
+      Assert.assertEquals(2, block1.refCnt());
+      // Reference count of block2 must be unchanged because we haven't shipped.
+      Assert.assertEquals(2, block2.refCnt());
+
+      // Do the shipped
+      scanner.shipped();
+      Assert.assertEquals(2, block1.refCnt());
+      Assert.assertEquals(1, block2.refCnt());
+
+      // Do the close
+      scanner.close();
+      Assert.assertEquals(1, block1.refCnt());
+      Assert.assertEquals(1, block2.refCnt());
+
+      Assert.assertTrue(defaultBC.evictBlocksByHfileName(hfileName) >= 2);
+      Assert.assertEquals(0, block1.refCnt());
+      Assert.assertEquals(0, block2.refCnt());
+
+      // Reload the block1 again.
+      block1 = reader.getDataBlockIndexReader()
+          .loadDataBlockWithScanInfo(firstCell, null, true, true, false, DataBlockEncoding.NONE)
+          .getHFileBlock();
+      Assert.assertFalse(block1.release());
+      Assert.assertEquals(1, block1.refCnt());
+      // Re-seek to the begin.
+      Assert.assertTrue(scanner.seekTo());
+      Assert.assertTrue(((HFileScannerImpl) scanner).curBlock == block1);
+      Assert.assertEquals(2, block1.refCnt());
+      // Return false because firstCell <= c[0]
+      Assert.assertFalse(scanner.seekBefore(firstCell));
+      // The block1 shouldn't be released because we still don't do the shipped or close.
+      Assert.assertEquals(2, block1.refCnt());
+
+      scanner.close();
+      Assert.assertEquals(1, block1.refCnt());
+      Assert.assertTrue(defaultBC.evictBlocksByHfileName(hfileName) >= 1);
+      Assert.assertEquals(0, block1.refCnt());
+    } finally {
+      fs.delete(dir, true);
+    }
+  }
+
+  @Test
+  public void testDefault() throws Exception {
+    testReleaseBlock(Algorithm.NONE, DataBlockEncoding.NONE);
+  }
+
+  @Test
+  public void testCompression() throws Exception {
+    testReleaseBlock(Algorithm.GZ, DataBlockEncoding.NONE);
+  }
+
+  @Test
+  public void testDataBlockEncoding() throws Exception {
+    testReleaseBlock(Algorithm.NONE, DataBlockEncoding.ROW_INDEX_V1);
+  }
+
+  @Test
+  public void testDataBlockEncodingAndCompression() throws Exception {
+    testReleaseBlock(Algorithm.GZ, DataBlockEncoding.ROW_INDEX_V1);
+  }
+}

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestLruBlockCache.java

@@ -955,12 +955,6 @@ public class TestLruBlockCache {
     public BlockType getBlockType() {
       return BlockType.DATA;
     }
-
-    @Override
-    public MemoryType getMemoryType() {
-      return MemoryType.EXCLUSIVE;
-    }
-
   }
 
   static void testMultiThreadGetAndEvictBlockInternal(BlockCache cache) throws Exception {

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/TestTinyLfuBlockCache.java

@@ -295,11 +295,6 @@ public class TestTinyLfuBlockCache {
       return BlockType.DATA;
     }
 
-    @Override
-    public MemoryType getMemoryType() {
-      return MemoryType.EXCLUSIVE;
-    }
-
     @Override
     public void serialize(ByteBuffer destination, boolean includeNextBlockMetadata) {
     }

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestBucketCacheRefCnt.java

@@ -32,7 +32,6 @@ import org.apache.hadoop.hbase.io.ByteBuffAllocator;
 import org.apache.hadoop.hbase.io.hfile.BlockCacheKey;
 import org.apache.hadoop.hbase.io.hfile.BlockType;
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.io.hfile.HFileBlock;
 import org.apache.hadoop.hbase.io.hfile.HFileContext;
 import org.apache.hadoop.hbase.io.hfile.HFileContextBuilder;
@@ -148,7 +147,6 @@ public class TestBucketCacheRefCnt {
       assertEquals(1, blk.refCnt());
 
       Cacheable block = cache.getBlock(key, false, false, false);
-      assertTrue(block.getMemoryType() == MemoryType.SHARED);
       assertTrue(block instanceof HFileBlock);
       assertTrue(((HFileBlock) block).getByteBuffAllocator() == alloc);
       assertEquals(2, block.refCnt());
@@ -157,7 +155,6 @@ public class TestBucketCacheRefCnt {
       assertEquals(3, block.refCnt());
 
       Cacheable newBlock = cache.getBlock(key, false, false, false);
-      assertTrue(newBlock.getMemoryType() == MemoryType.SHARED);
       assertTrue(newBlock instanceof HFileBlock);
       assertTrue(((HFileBlock) newBlock).getByteBuffAllocator() == alloc);
       assertEquals(4, newBlock.refCnt());

hbase-server/src/test/java/org/apache/hadoop/hbase/io/hfile/bucket/TestByteBufferIOEngine.java

@@ -22,7 +22,6 @@ import java.nio.ByteBuffer;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.io.ByteBuffAllocator;
 import org.apache.hadoop.hbase.io.hfile.Cacheable;
-import org.apache.hadoop.hbase.io.hfile.Cacheable.MemoryType;
 import org.apache.hadoop.hbase.io.hfile.CacheableDeserializer;
 import org.apache.hadoop.hbase.io.hfile.CacheableDeserializerIdManager;
 import org.apache.hadoop.hbase.nio.ByteBuff;
@@ -127,7 +126,7 @@ public class TestByteBufferIOEngine {
     private int identifier;
 
     @Override
-    public Cacheable deserialize(final ByteBuff b, ByteBuffAllocator alloc, MemoryType memType)
+    public Cacheable deserialize(final ByteBuff b, ByteBuffAllocator alloc)
         throws IOException {
       this.buf = b;
       return null;