Revert "HBASE-27013 Introduce read all bytes when using pread for prefetch (#4414)"

This reverts commit 0eb1a4e5ed.

hbase-common/src/main/java/org/apache/hadoop/hbase/HConstants.java

@@ -1011,13 +1011,6 @@ public final class HConstants {
   public static final long HBASE_CLIENT_SCANNER_ONHEAP_BLOCK_CACHE_FIXED_SIZE_DEFAULT =
     32 * 1024 * 1024L;
 
-  /**
-   * Configuration key for setting pread must read both necessaryLen and extraLen, default is
-   * disabled. This is an optimized flag for reading HFile from blob storage.
-   */
-  public static final String HFILE_PREAD_ALL_BYTES_ENABLED_KEY = "hfile.pread.all.bytes.enabled";
-  public static final boolean HFILE_PREAD_ALL_BYTES_ENABLED_DEFAULT = false;
-
   /*
    * Minimum percentage of free heap necessary for a successful cluster startup.
    */

hbase-common/src/main/java/org/apache/hadoop/hbase/io/util/BlockIOUtils.java

@@ -228,43 +228,21 @@ public final class BlockIOUtils {
    */
   public static boolean preadWithExtra(ByteBuff buff, FSDataInputStream dis, long position,
     int necessaryLen, int extraLen) throws IOException {
-    return preadWithExtra(buff, dis, position, necessaryLen, extraLen, false);
-  }
-
-  /**
-   * Read from an input stream at least <code>necessaryLen</code> and if possible,
-   * <code>extraLen</code> also if available. Analogous to
-   * {@link IOUtils#readFully(InputStream, byte[], int, int)}, but uses positional read and
-   * specifies a number of "extra" bytes that would be desirable but not absolutely necessary to
-   * read. If the input stream supports ByteBufferPositionedReadable, it reads to the byte buffer
-   * directly, and does not allocate a temporary byte array.
-   * @param buff         ByteBuff to read into.
-   * @param dis          the input stream to read from
-   * @param position     the position within the stream from which to start reading
-   * @param necessaryLen the number of bytes that are absolutely necessary to read
-   * @param extraLen     the number of extra bytes that would be nice to read
-   * @param readAllBytes whether we must read the necessaryLen and extraLen
-   * @return true if and only if extraLen is > 0 and reading those extra bytes was successful
-   * @throws IOException if failed to read the necessary bytes
-   */
-  public static boolean preadWithExtra(ByteBuff buff, FSDataInputStream dis, long position,
-    int necessaryLen, int extraLen, boolean readAllBytes) throws IOException {
     boolean preadbytebuffer = dis.hasCapability("in:preadbytebuffer");
 
     if (preadbytebuffer) {
-      return preadWithExtraDirectly(buff, dis, position, necessaryLen, extraLen, readAllBytes);
+      return preadWithExtraDirectly(buff, dis, position, necessaryLen, extraLen);
     } else {
-      return preadWithExtraOnHeap(buff, dis, position, necessaryLen, extraLen, readAllBytes);
+      return preadWithExtraOnHeap(buff, dis, position, necessaryLen, extraLen);
     }
   }
 
   private static boolean preadWithExtraOnHeap(ByteBuff buff, FSDataInputStream dis, long position,
-    int necessaryLen, int extraLen, boolean readAllBytes) throws IOException {
+    int necessaryLen, int extraLen) throws IOException {
     int remain = necessaryLen + extraLen;
     byte[] buf = new byte[remain];
     int bytesRead = 0;
-    int lengthMustRead = readAllBytes ? remain : necessaryLen;
-    while (bytesRead < lengthMustRead) {
+    while (bytesRead < necessaryLen) {
       int ret = dis.read(position + bytesRead, buf, bytesRead, remain);
       if (ret < 0) {
         throw new IOException("Premature EOF from inputStream (positional read returned " + ret
@@ -279,12 +257,11 @@ public final class BlockIOUtils {
   }
 
   private static boolean preadWithExtraDirectly(ByteBuff buff, FSDataInputStream dis, long position,
-    int necessaryLen, int extraLen, boolean readAllBytes) throws IOException {
+    int necessaryLen, int extraLen) throws IOException {
     int remain = necessaryLen + extraLen, bytesRead = 0, idx = 0;
     ByteBuffer[] buffers = buff.nioByteBuffers();
     ByteBuffer cur = buffers[idx];
-    int lengthMustRead = readAllBytes ? remain : necessaryLen;
-    while (bytesRead < lengthMustRead) {
+    while (bytesRead < necessaryLen) {
       int ret;
       while (!cur.hasRemaining()) {
         if (++idx >= buffers.length) {

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

@@ -1349,8 +1349,6 @@ public class HFileBlock implements Cacheable {
 
     private final Lock streamLock = new ReentrantLock();
 
-    private final boolean isPreadAllBytes;
-
     FSReaderImpl(ReaderContext readerContext, HFileContext fileContext, ByteBuffAllocator allocator,
       Configuration conf) throws IOException {
       this.fileSize = readerContext.getFileSize();
@@ -1367,7 +1365,6 @@ public class HFileBlock implements Cacheable {
       this.streamWrapper.prepareForBlockReader(!fileContext.isUseHBaseChecksum());
       defaultDecodingCtx = new HFileBlockDefaultDecodingContext(conf, fileContext);
       encodedBlockDecodingCtx = defaultDecodingCtx;
-      isPreadAllBytes = readerContext.isPreadAllBytes();
     }
 
     @Override
@@ -1456,9 +1453,7 @@ public class HFileBlock implements Cacheable {
       } else {
         // Positional read. Better for random reads; or when the streamLock is already locked.
         int extraSize = peekIntoNextBlock ? hdrSize : 0;
-        if (
-          !BlockIOUtils.preadWithExtra(dest, istream, fileOffset, size, extraSize, isPreadAllBytes)
-        ) {
+        if (!BlockIOUtils.preadWithExtra(dest, istream, fileOffset, size, extraSize)) {
           // did not read the next block header.
           return false;
         }

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

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.io.hfile;
 
 import org.apache.hadoop.fs.Path;
-import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.fs.HFileSystem;
 import org.apache.hadoop.hbase.io.FSDataInputStreamWrapper;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -40,7 +39,6 @@ public class ReaderContext {
   private final HFileSystem hfs;
   private final boolean primaryReplicaReader;
   private final ReaderType type;
-  private final boolean preadAllBytes;
 
   public ReaderContext(Path filePath, FSDataInputStreamWrapper fsdis, long fileSize,
     HFileSystem hfs, boolean primaryReplicaReader, ReaderType type) {
@@ -50,8 +48,6 @@ public class ReaderContext {
     this.hfs = hfs;
     this.primaryReplicaReader = primaryReplicaReader;
     this.type = type;
-    this.preadAllBytes = hfs.getConf().getBoolean(HConstants.HFILE_PREAD_ALL_BYTES_ENABLED_KEY,
-      HConstants.HFILE_PREAD_ALL_BYTES_ENABLED_DEFAULT);
   }
 
   public Path getFilePath() {
@@ -77,8 +73,4 @@ public class ReaderContext {
   public ReaderType getReaderType() {
     return this.type;
   }
-
-  public boolean isPreadAllBytes() {
-    return preadAllBytes;
-  }
 }

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

@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.io.hfile;
 
 import static org.junit.Assert.assertArrayEquals;
-import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
@@ -29,23 +28,15 @@ import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.verifyNoMoreInteractions;
 import static org.mockito.Mockito.when;
 
-import java.io.DataOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.nio.ByteBuffer;
-import java.util.Random;
-import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FSDataInputStream;
 import org.apache.hadoop.fs.FSDataOutputStream;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hbase.HBaseClassTestRule;
 import org.apache.hadoop.hbase.HBaseTestingUtil;
-import org.apache.hadoop.hbase.HConstants;
-import org.apache.hadoop.hbase.fs.HFileSystem;
-import org.apache.hadoop.hbase.io.ByteBuffAllocator;
-import org.apache.hadoop.hbase.io.FSDataInputStreamWrapper;
-import org.apache.hadoop.hbase.io.compress.Compression;
 import org.apache.hadoop.hbase.io.util.BlockIOUtils;
 import org.apache.hadoop.hbase.nio.ByteBuff;
 import org.apache.hadoop.hbase.nio.MultiByteBuff;
@@ -53,13 +44,11 @@ import org.apache.hadoop.hbase.nio.SingleByteBuff;
 import org.apache.hadoop.hbase.testclassification.IOTests;
 import org.apache.hadoop.hbase.testclassification.SmallTests;
 import org.apache.hadoop.hbase.util.Bytes;
-import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
 import org.junit.ClassRule;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.junit.rules.ExpectedException;
-import org.junit.rules.TestName;
 
 @Category({ IOTests.class, SmallTests.class })
 public class TestBlockIOUtils {
@@ -68,17 +57,11 @@ public class TestBlockIOUtils {
   public static final HBaseClassTestRule CLASS_RULE =
     HBaseClassTestRule.forClass(TestBlockIOUtils.class);
 
-  @Rule
-  public TestName testName = new TestName();
-
   @Rule
   public ExpectedException exception = ExpectedException.none();
 
   private static final HBaseTestingUtil TEST_UTIL = new HBaseTestingUtil();
 
-  private static final int NUM_TEST_BLOCKS = 2;
-  private static final Compression.Algorithm COMPRESSION_ALGO = Compression.Algorithm.GZ;
-
   @Test
   public void testIsByteBufferReadable() throws IOException {
     FileSystem fs = TEST_UTIL.getTestFileSystem();
@@ -109,103 +92,6 @@ public class TestBlockIOUtils {
     assertArrayEquals(Bytes.toBytes(s), heapBuf);
   }
 
-  @Test
-  public void testPreadWithReadFullBytes() throws IOException {
-    testPreadReadFullBytesInternal(true, EnvironmentEdgeManager.currentTime());
-  }
-
-  @Test
-  public void testPreadWithoutReadFullBytes() throws IOException {
-    testPreadReadFullBytesInternal(false, EnvironmentEdgeManager.currentTime());
-  }
-
-  private void testPreadReadFullBytesInternal(boolean readAllBytes, long randomSeed)
-    throws IOException {
-    Configuration conf = TEST_UTIL.getConfiguration();
-    conf.setBoolean(HConstants.HFILE_PREAD_ALL_BYTES_ENABLED_KEY, readAllBytes);
-    FileSystem fs = TEST_UTIL.getTestFileSystem();
-    Path path = new Path(TEST_UTIL.getDataTestDirOnTestFS(), testName.getMethodName());
-    // give a fixed seed such we can see failure easily.
-    Random rand = new Random(randomSeed);
-    long totalDataBlockBytes =
-      writeBlocks(TEST_UTIL.getConfiguration(), rand, COMPRESSION_ALGO, path);
-    readDataBlocksAndVerify(fs, path, COMPRESSION_ALGO, totalDataBlockBytes);
-  }
-
-  private long writeBlocks(Configuration conf, Random rand, Compression.Algorithm compressAlgo,
-    Path path) throws IOException {
-    FileSystem fs = HFileSystem.get(conf);
-    FSDataOutputStream os = fs.create(path);
-    HFileContext meta =
-      new HFileContextBuilder().withHBaseCheckSum(true).withCompression(compressAlgo).build();
-    HFileBlock.Writer hbw = new HFileBlock.Writer(conf, null, meta);
-    long totalDataBlockBytes = 0;
-    for (int i = 0; i < NUM_TEST_BLOCKS; ++i) {
-      int blockTypeOrdinal = rand.nextInt(BlockType.values().length);
-      if (blockTypeOrdinal == BlockType.ENCODED_DATA.ordinal()) {
-        blockTypeOrdinal = BlockType.DATA.ordinal();
-      }
-      BlockType bt = BlockType.values()[blockTypeOrdinal];
-      DataOutputStream dos = hbw.startWriting(bt);
-      int size = rand.nextInt(500);
-      for (int j = 0; j < size; ++j) {
-        dos.writeShort(i + 1);
-        dos.writeInt(j + 1);
-      }
-
-      hbw.writeHeaderAndData(os);
-      totalDataBlockBytes += hbw.getOnDiskSizeWithHeader();
-    }
-    // append a dummy trailer and in a actual HFile it should have more data.
-    FixedFileTrailer trailer = new FixedFileTrailer(3, 3);
-    trailer.setFirstDataBlockOffset(0);
-    trailer.setLastDataBlockOffset(totalDataBlockBytes);
-    trailer.setComparatorClass(meta.getCellComparator().getClass());
-    trailer.setDataIndexCount(NUM_TEST_BLOCKS);
-    trailer.setCompressionCodec(compressAlgo);
-    trailer.serialize(os);
-    // close the stream
-    os.close();
-    return totalDataBlockBytes;
-  }
-
-  private void readDataBlocksAndVerify(FileSystem fs, Path path, Compression.Algorithm compressAlgo,
-    long totalDataBlockBytes) throws IOException {
-    FSDataInputStream is = fs.open(path);
-    HFileContext fileContext =
-      new HFileContextBuilder().withHBaseCheckSum(true).withCompression(compressAlgo).build();
-    ReaderContext context =
-      new ReaderContextBuilder().withInputStreamWrapper(new FSDataInputStreamWrapper(is))
-        .withReaderType(ReaderContext.ReaderType.PREAD).withFileSize(totalDataBlockBytes)
-        .withFilePath(path).withFileSystem(fs).build();
-    HFileBlock.FSReader hbr =
-      new HFileBlock.FSReaderImpl(context, fileContext, ByteBuffAllocator.HEAP, fs.getConf());
-
-    long onDiskSizeOfNextBlock = -1;
-    long offset = 0;
-    int numOfReadBlock = 0;
-    // offset and totalBytes shares the same logic in the HFilePreadReader
-    while (offset < totalDataBlockBytes) {
-      HFileBlock block = hbr.readBlockData(offset, onDiskSizeOfNextBlock, true, false, false);
-      numOfReadBlock++;
-      try {
-        onDiskSizeOfNextBlock = block.getNextBlockOnDiskSize();
-        offset += block.getOnDiskSizeWithHeader();
-      } finally {
-        block.release();
-      }
-    }
-    assertEquals(totalDataBlockBytes, offset);
-    assertEquals(NUM_TEST_BLOCKS, numOfReadBlock);
-    deleteFile(fs, path);
-  }
-
-  private void deleteFile(FileSystem fs, Path path) throws IOException {
-    if (fs.exists(path)) {
-      fs.delete(path, true);
-    }
-  }
-
   @Test
   public void testReadWithExtra() throws IOException {
     FileSystem fs = TEST_UTIL.getTestFileSystem();