org.apache.hadoop.hbase.io.hfile.HFileBlock Maven / Gradle / Ivy
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* 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 java.io.DataInputStream;
import java.io.DataOutput;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.ByteBuffer;
import java.util.concurrent.atomic.AtomicReference;
import java.util.concurrent.locks.Lock;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.fs.FSDataInputStream;
import org.apache.hadoop.fs.FSDataOutputStream;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.fs.HFileSystem;
import org.apache.hadoop.hbase.io.ByteArrayOutputStream;
import org.apache.hadoop.hbase.io.ByteBufferInputStream;
import org.apache.hadoop.hbase.io.FSDataInputStreamWrapper;
import org.apache.hadoop.hbase.io.encoding.DataBlockEncoding;
import org.apache.hadoop.hbase.io.encoding.HFileBlockDecodingContext;
import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultDecodingContext;
import org.apache.hadoop.hbase.io.encoding.HFileBlockDefaultEncodingContext;
import org.apache.hadoop.hbase.io.encoding.HFileBlockEncodingContext;
import org.apache.hadoop.hbase.util.ByteBufferUtils;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.ChecksumType;
import org.apache.hadoop.hbase.util.ClassSize;
import org.apache.hadoop.io.IOUtils;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.base.Preconditions;
/**
* Reads {@link HFile} version 2 blocks to HFiles and via {@link Cacheable} Interface to caches.
* Version 2 was introduced in hbase-0.92.0. No longer has support for version 1 blocks since
* hbase-1.3.0.
*
* Version 1 was the original file block. Version 2 was introduced when we changed the hbase file
* format to support multi-level block indexes and compound bloom filters (HBASE-3857).
*
*
HFileBlock: Version 2
* In version 2, a block is structured as follows:
*
* - Header: See Writer#putHeader() for where header is written; header total size is
* HFILEBLOCK_HEADER_SIZE
*
* - 0. blockType: Magic record identifying the {@link BlockType} (8 bytes):
* e.g.
DATABLK*
* - 1. onDiskSizeWithoutHeader: Compressed -- a.k.a 'on disk' -- block size, excluding header,
* but including tailing checksum bytes (4 bytes)
*
- 2. uncompressedSizeWithoutHeader: Uncompressed block size, excluding header, and excluding
* checksum bytes (4 bytes)
*
- 3. prevBlockOffset: The offset of the previous block of the same type (8 bytes). This is
* used to navigate to the previous block without having to go to the block index
*
- 4: For minorVersions >=1, the ordinal describing checksum type (1 byte)
*
- 5: For minorVersions >=1, the number of data bytes/checksum chunk (4 bytes)
*
- 6: onDiskDataSizeWithHeader: For minorVersions >=1, the size of data 'on disk', including
* header, excluding checksums (4 bytes)
*
*
* - Raw/Compressed/Encrypted/Encoded data: The compression
* algorithm is the same for all the blocks in an {@link HFile}. If compression is NONE, this is
* just raw, serialized Cells.
*
- Tail: For minorVersions >=1, a series of 4 byte checksums, one each for
* the number of bytes specified by bytesPerChecksum.
*
* Caching
* Caches cache whole blocks with trailing checksums if any. We then tag on some metadata, the
* content of BLOCK_METADATA_SPACE which will be flag on if we are doing 'hbase'
* checksums and then the offset into the file which is needed when we re-make a cache key
* when we return the block to the cache as 'done'. See {@link Cacheable#serialize(ByteBuffer)} and
* {@link Cacheable#getDeserializer()}.
*
* TODO: Should we cache the checksums? Down in Writer#getBlockForCaching(CacheConfig) where
* we make a block to cache-on-write, there is an attempt at turning off checksums. This is not the
* only place we get blocks to cache. We also will cache the raw return from an hdfs read. In this
* case, the checksums may be present. If the cache is backed by something that doesn't do ECC,
* say an SSD, we might want to preserve checksums. For now this is open question.
*
TODO: Over in BucketCache, we save a block allocation by doing a custom serialization.
* Be sure to change it if serialization changes in here. Could we add a method here that takes an
* IOEngine and that then serializes to it rather than expose our internals over in BucketCache?
* IOEngine is in the bucket subpackage. Pull it up? Then this class knows about bucketcache. Ugh.
*/
@InterfaceAudience.Private
@edu.umd.cs.findbugs.annotations.SuppressWarnings(value="HE_EQUALS_USE_HASHCODE",
justification="Fix!!! Fine for now bug FIXXXXXXX!!!!")
public class HFileBlock implements Cacheable {
private static final Log LOG = LogFactory.getLog(HFileBlock.class);
/** Type of block. Header field 0. */
private BlockType blockType;
/**
* Size on disk excluding header, including checksum. Header field 1.
* @see Writer#putHeader(byte[], int, int, int, int)
*/
private int onDiskSizeWithoutHeader;
/**
* Size of pure data. Does not include header or checksums. Header field 2.
* @see Writer#putHeader(byte[], int, int, int, int)
*/
private int uncompressedSizeWithoutHeader;
/**
* The offset of the previous block on disk. Header field 3.
* @see Writer#putHeader(byte[], int, int, int, int)
*/
private long prevBlockOffset;
/**
* Size on disk of header + data. Excludes checksum. Header field 6,
* OR calculated from {@link #onDiskSizeWithoutHeader} when using HDFS checksum.
* @see Writer#putHeader(byte[], int, int, int, int)
*/
private int onDiskDataSizeWithHeader;
/**
* The in-memory representation of the hfile block. Can be on or offheap. Can be backed by
* a single ByteBuffer or by many. Make no assumptions.
*
*
Be careful reading from this buf. Duplicate and work on the duplicate or if
* not, be sure to reset position and limit else trouble down the road.
*
*
TODO: Make this read-only once made.
*/
private ByteBuffer buf;
/** Meta data that holds meta information on the hfileblock.
*/
private HFileContext fileContext;
/**
* The offset of this block in the file. Populated by the reader for
* convenience of access. This offset is not part of the block header.
*/
private long offset = UNSET;
/**
* The on-disk size of the next block, including the header and checksums if present, obtained by
* peeking into the first {@link HConstants#HFILEBLOCK_HEADER_SIZE} bytes of the next block's
* header, or UNSET if unknown.
*
* Blocks try to carry the size of the next block to read in this data member. They will even have
* this value when served from cache. Could save a seek in the case where we are iterating through
* a file and some of the blocks come from cache. If from cache, then having this info to hand
* will save us doing a seek to read the header so we can read the body of a block.
* TODO: see how effective this is at saving seeks.
*/
private int nextBlockOnDiskSize = UNSET;
/**
* On a checksum failure, do these many succeeding read requests using hdfs checksums before
* auto-reenabling hbase checksum verification.
*/
static final int CHECKSUM_VERIFICATION_NUM_IO_THRESHOLD = 3;
private static int UNSET = -1;
public static final boolean FILL_HEADER = true;
public static final boolean DONT_FILL_HEADER = false;
public static final int BYTE_BUFFER_HEAP_SIZE = (int) ClassSize.estimateBase(
ByteBuffer.wrap(new byte[0], 0, 0).getClass(), false);
/**
* Space for metadata on a block that gets stored along with the block when we cache it.
* There are a few bytes stuck on the end of the HFileBlock that we pull in from HDFS (note,
* when we read from HDFS, we pull in an HFileBlock AND the header of the next block if one).
* 8 bytes are offset of this block (long) in the file. Offset is important because
* used when we remake the CacheKey when we return the block to cache when done. There is also
* a flag on whether checksumming is being done by hbase or not. See class comment for note on
* uncertain state of checksumming of blocks that come out of cache (should we or should we not?).
* Finally there 4 bytes to hold the length of the next block which can save a seek on occasion.
*
This EXTRA came in with original commit of the bucketcache, HBASE-7404. Was formerly
* known as EXTRA_SERIALIZATION_SPACE.
*/
static final int BLOCK_METADATA_SPACE = Bytes.SIZEOF_BYTE + Bytes.SIZEOF_LONG + Bytes.SIZEOF_INT;
/**
* Each checksum value is an integer that can be stored in 4 bytes.
*/
static final int CHECKSUM_SIZE = Bytes.SIZEOF_INT;
static final byte[] DUMMY_HEADER_NO_CHECKSUM =
new byte[HConstants.HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM];
/**
* Used deserializing blocks from Cache.
*
*
* ++++++++++++++
* + HFileBlock +
* ++++++++++++++
* + Checksums + <= Optional
* ++++++++++++++
* + Metadata! +
* ++++++++++++++
*
* @see #serialize(ByteBuffer)
*/
static final CacheableDeserializer BLOCK_DESERIALIZER =
new CacheableDeserializer() {
@Override
public HFileBlock deserialize(ByteBuffer buf, boolean reuse) throws IOException{
// The buf has the file block followed by block metadata.
// Set limit to just before the BLOCK_METADATA_SPACE then rewind.
buf.limit(buf.limit() - BLOCK_METADATA_SPACE).rewind();
// Get a new buffer to pass the HFileBlock for it to 'own'.
ByteBuffer newByteBuff;
if (reuse) {
newByteBuff = buf.slice();
} else {
int len = buf.limit();
newByteBuff = ByteBuffer.allocate(len);
ByteBufferUtils.copyFromBufferToBuffer(newByteBuff, buf, buf.position(), 0, len);
}
// Read out the BLOCK_METADATA_SPACE content and shove into our HFileBlock.
buf.position(buf.limit());
buf.limit(buf.limit() + HFileBlock.BLOCK_METADATA_SPACE);
boolean usesChecksum = buf.get() == (byte)1;
long offset = buf.getLong();
int nextBlockOnDiskSize = buf.getInt();
HFileBlock hFileBlock =
new HFileBlock(newByteBuff, usesChecksum, offset, nextBlockOnDiskSize, null);
return hFileBlock;
}
@Override
public int getDeserialiserIdentifier() {
return DESERIALIZER_IDENTIFIER;
}
@Override
public HFileBlock deserialize(ByteBuffer b) throws IOException {
return deserialize(b, false);
}
};
private static final int DESERIALIZER_IDENTIFIER;
static {
DESERIALIZER_IDENTIFIER =
CacheableDeserializerIdManager.registerDeserializer(BLOCK_DESERIALIZER);
}
// Todo: encapsulate Header related logic in this inner class.
static class Header {
// Format of header is:
// 8 bytes - block magic
// 4 bytes int - onDiskSizeWithoutHeader
// 4 bytes int - uncompressedSizeWithoutHeader
// 8 bytes long - prevBlockOffset
// The following 3 are only present if header contains checksum information
// 1 byte - checksum type
// 4 byte int - bytes per checksum
// 4 byte int - onDiskDataSizeWithHeader
static int BLOCK_MAGIC_INDEX = 0;
static int ON_DISK_SIZE_WITHOUT_HEADER_INDEX = 8;
static int UNCOMPRESSED_SIZE_WITHOUT_HEADER_INDEX = 12;
static int PREV_BLOCK_OFFSET_INDEX = 16;
static int CHECKSUM_TYPE_INDEX = 24;
static int BYTES_PER_CHECKSUM_INDEX = 25;
static int ON_DISK_DATA_SIZE_WITH_HEADER_INDEX = 29;
}
/**
* Copy constructor. Creates a shallow copy of {@code that}'s buffer.
*/
private HFileBlock(HFileBlock that) {
this.blockType = that.blockType;
this.onDiskSizeWithoutHeader = that.onDiskSizeWithoutHeader;
this.uncompressedSizeWithoutHeader = that.uncompressedSizeWithoutHeader;
this.prevBlockOffset = that.prevBlockOffset;
this.buf = that.buf.duplicate();
this.offset = that.offset;
this.onDiskDataSizeWithHeader = that.onDiskDataSizeWithHeader;
this.fileContext = that.fileContext;
this.nextBlockOnDiskSize = that.nextBlockOnDiskSize;
}
/**
* Creates a new {@link HFile} block from the given fields. This constructor
* is used only while writing blocks and caching,
* and is sitting in a byte buffer and we want to stuff the block into cache.
* See {@link Writer#getBlockForCaching(CacheConfig)}.
*
* TODO: The caller presumes no checksumming
* required of this block instance since going into cache; checksum already verified on
* underlying block data pulled in from filesystem. Is that correct? What if cache is SSD?
*
* @param blockType the type of this block, see {@link BlockType}
* @param onDiskSizeWithoutHeader see {@link #onDiskSizeWithoutHeader}
* @param uncompressedSizeWithoutHeader see {@link #uncompressedSizeWithoutHeader}
* @param prevBlockOffset see {@link #prevBlockOffset}
* @param b block header ({@link HConstants#HFILEBLOCK_HEADER_SIZE} bytes)
* @param fillHeader when true, write the first 4 header fields into passed buffer.
* @param offset the file offset the block was read from
* @param onDiskDataSizeWithHeader see {@link #onDiskDataSizeWithHeader}
* @param fileContext HFile meta data
*/
HFileBlock(BlockType blockType, int onDiskSizeWithoutHeader, int uncompressedSizeWithoutHeader,
long prevBlockOffset, ByteBuffer b, boolean fillHeader, long offset,
final int nextBlockOnDiskSize, int onDiskDataSizeWithHeader, HFileContext fileContext) {
init(blockType, onDiskSizeWithoutHeader, uncompressedSizeWithoutHeader,
prevBlockOffset, offset, onDiskDataSizeWithHeader, nextBlockOnDiskSize, fileContext);
this.buf = b;
if (fillHeader) {
overwriteHeader();
}
this.buf.rewind();
}
/**
* Creates a block from an existing buffer starting with a header. Rewinds
* and takes ownership of the buffer. By definition of rewind, ignores the
* buffer position, but if you slice the buffer beforehand, it will rewind
* to that point.
* @param buf Has header, content, and trailing checksums if present.
*/
HFileBlock(ByteBuffer buf, boolean usesHBaseChecksum, final long offset,
final int nextBlockOnDiskSize, HFileContext fileContext) throws IOException {
buf.rewind();
final BlockType blockType = BlockType.read(buf);
final int onDiskSizeWithoutHeader = buf.getInt(Header.ON_DISK_SIZE_WITHOUT_HEADER_INDEX);
final int uncompressedSizeWithoutHeader =
buf.getInt(Header.UNCOMPRESSED_SIZE_WITHOUT_HEADER_INDEX);
final long prevBlockOffset = buf.getLong(Header.PREV_BLOCK_OFFSET_INDEX);
// This constructor is called when we deserialize a block from cache and when we read a block in
// from the fs. fileCache is null when deserialized from cache so need to make up one.
HFileContextBuilder fileContextBuilder = fileContext != null?
new HFileContextBuilder(fileContext): new HFileContextBuilder();
fileContextBuilder.withHBaseCheckSum(usesHBaseChecksum);
int onDiskDataSizeWithHeader;
if (usesHBaseChecksum) {
byte checksumType = buf.get(Header.CHECKSUM_TYPE_INDEX);
int bytesPerChecksum = buf.getInt(Header.BYTES_PER_CHECKSUM_INDEX);
onDiskDataSizeWithHeader = buf.getInt(Header.ON_DISK_DATA_SIZE_WITH_HEADER_INDEX);
// Use the checksum type and bytes per checksum from header, not from filecontext.
fileContextBuilder.withChecksumType(ChecksumType.codeToType(checksumType));
fileContextBuilder.withBytesPerCheckSum(bytesPerChecksum);
} else {
fileContextBuilder.withChecksumType(ChecksumType.NULL);
fileContextBuilder.withBytesPerCheckSum(0);
// Need to fix onDiskDataSizeWithHeader; there are not checksums after-block-data
onDiskDataSizeWithHeader = onDiskSizeWithoutHeader + headerSize(usesHBaseChecksum);
}
fileContext = fileContextBuilder.build();
assert usesHBaseChecksum == fileContext.isUseHBaseChecksum();
init(blockType, onDiskSizeWithoutHeader, uncompressedSizeWithoutHeader,
prevBlockOffset, offset, onDiskDataSizeWithHeader, nextBlockOnDiskSize, fileContext);
this.offset = offset;
this.buf = buf;
this.buf.rewind();
}
/**
* Called from constructors.
*/
private void init(BlockType blockType, int onDiskSizeWithoutHeader,
int uncompressedSizeWithoutHeader, long prevBlockOffset,
long offset, int onDiskDataSizeWithHeader, final int nextBlockOnDiskSize,
HFileContext fileContext) {
this.blockType = blockType;
this.onDiskSizeWithoutHeader = onDiskSizeWithoutHeader;
this.uncompressedSizeWithoutHeader = uncompressedSizeWithoutHeader;
this.prevBlockOffset = prevBlockOffset;
this.offset = offset;
this.onDiskDataSizeWithHeader = onDiskDataSizeWithHeader;
this.nextBlockOnDiskSize = nextBlockOnDiskSize;
this.fileContext = fileContext;
}
/**
* Parse total ondisk size including header and checksum.
* @param headerBuf Header ByteBuffer. Presumed exact size of header.
* @param verifyChecksum true if checksum verification is in use.
* @return Size of the block with header included.
*/
private static int getOnDiskSizeWithHeader(final ByteBuffer headerBuf, boolean verifyChecksum) {
return headerBuf.getInt(Header.ON_DISK_SIZE_WITHOUT_HEADER_INDEX) +
headerSize(verifyChecksum);
}
/**
* @return the on-disk size of the next block (including the header size and any checksums if
* present) read by peeking into the next block's header; use as a hint when doing
* a read of the next block when scanning or running over a file.
*/
public int getNextBlockOnDiskSize() {
return nextBlockOnDiskSize;
}
@Override
public BlockType getBlockType() {
return blockType;
}
/** @return get data block encoding id that was used to encode this block */
public short getDataBlockEncodingId() {
if (blockType != BlockType.ENCODED_DATA) {
throw new IllegalArgumentException("Querying encoder ID of a block " +
"of type other than " + BlockType.ENCODED_DATA + ": " + blockType);
}
return buf.getShort(headerSize());
}
/**
* @return the on-disk size of header + data part + checksum.
*/
public int getOnDiskSizeWithHeader() {
return onDiskSizeWithoutHeader + headerSize();
}
/**
* @return the on-disk size of the data part + checksum (header excluded).
*/
int getOnDiskSizeWithoutHeader() {
return onDiskSizeWithoutHeader;
}
/**
* @return the uncompressed size of data part (header and checksum excluded).
*/
public int getUncompressedSizeWithoutHeader() {
return uncompressedSizeWithoutHeader;
}
/**
* @return the offset of the previous block of the same type in the file, or
* -1 if unknown
*/
long getPrevBlockOffset() {
return prevBlockOffset;
}
/**
* Rewinds {@code buf} and writes first 4 header fields. {@code buf} position
* is modified as side-effect.
*/
private void overwriteHeader() {
buf.rewind();
blockType.write(buf);
buf.putInt(onDiskSizeWithoutHeader);
buf.putInt(uncompressedSizeWithoutHeader);
buf.putLong(prevBlockOffset);
if (this.fileContext.isUseHBaseChecksum()) {
buf.put(fileContext.getChecksumType().getCode());
buf.putInt(fileContext.getBytesPerChecksum());
buf.putInt(onDiskDataSizeWithHeader);
}
}
/**
* Returns a buffer that does not include the header or checksum.
*
* @return the buffer with header skipped and checksum omitted.
*/
public ByteBuffer getBufferWithoutHeader() {
ByteBuffer dup = getBufferReadOnly();
// Now set it up so Buffer spans content only -- no header or no checksums.
dup.position(headerSize()).limit(buf.limit() - totalChecksumBytes());
return dup.slice();
}
/**
* Returns a read-only duplicate of the buffer this block stores internally ready to be read.
* Clients must not modify the buffer object though they may set position and limit on the
* returned buffer since we pass back a duplicate. This method has to be public because it is used
* used in {@link org.apache.hadoop.hbase.util.CompoundBloomFilter}
* to avoid object creation on every Bloom
* filter lookup, but has to be used with caution. Buffer holds header, block content,
* and any follow-on checksums if present.
*
* @return the buffer of this block for read-only operations
*/
public ByteBuffer getBufferReadOnly() {
ByteBuffer dup = this.buf.duplicate();
return dup;
}
private void sanityCheckAssertion(long valueFromBuf, long valueFromField,
String fieldName) throws IOException {
if (valueFromBuf != valueFromField) {
throw new AssertionError(fieldName + " in the buffer (" + valueFromBuf
+ ") is different from that in the field (" + valueFromField + ")");
}
}
private void sanityCheckAssertion(BlockType valueFromBuf, BlockType valueFromField)
throws IOException {
if (valueFromBuf != valueFromField) {
throw new IOException("Block type stored in the buffer: " +
valueFromBuf + ", block type field: " + valueFromField);
}
}
/**
* Checks if the block is internally consistent, i.e. the first
* {@link HConstants#HFILEBLOCK_HEADER_SIZE} bytes of the buffer contain a
* valid header consistent with the fields. Assumes a packed block structure.
* This function is primary for testing and debugging, and is not
* thread-safe, because it alters the internal buffer pointer.
* Used by tests only.
*/
@VisibleForTesting
void sanityCheck() throws IOException {
// Duplicate so no side-effects
ByteBuffer dup = this.buf.duplicate();
dup.rewind();
sanityCheckAssertion(BlockType.read(dup), blockType);
sanityCheckAssertion(dup.getInt(), onDiskSizeWithoutHeader, "onDiskSizeWithoutHeader");
sanityCheckAssertion(dup.getInt(), uncompressedSizeWithoutHeader,
"uncompressedSizeWithoutHeader");
sanityCheckAssertion(dup.getLong(), prevBlockOffset, "prevBlockOffset");
if (this.fileContext.isUseHBaseChecksum()) {
sanityCheckAssertion(dup.get(), this.fileContext.getChecksumType().getCode(), "checksumType");
sanityCheckAssertion(dup.getInt(), this.fileContext.getBytesPerChecksum(),
"bytesPerChecksum");
sanityCheckAssertion(dup.getInt(), onDiskDataSizeWithHeader, "onDiskDataSizeWithHeader");
}
int cksumBytes = totalChecksumBytes();
int expectedBufLimit = onDiskDataSizeWithHeader + cksumBytes;
if (dup.limit() != expectedBufLimit) {
throw new AssertionError("Expected limit " + expectedBufLimit + ", got " + dup.limit());
}
// We might optionally allocate HFILEBLOCK_HEADER_SIZE more bytes to read the next
// block's header, so there are two sensible values for buffer capacity.
int hdrSize = headerSize();
if (dup.capacity() != expectedBufLimit && dup.capacity() != expectedBufLimit + hdrSize) {
throw new AssertionError("Invalid buffer capacity: " + dup.capacity() +
", expected " + expectedBufLimit + " or " + (expectedBufLimit + hdrSize));
}
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder()
.append("[")
.append("blockType=").append(blockType)
.append(", fileOffset=").append(offset)
.append(", headerSize=").append(headerSize())
.append(", onDiskSizeWithoutHeader=").append(onDiskSizeWithoutHeader)
.append(", uncompressedSizeWithoutHeader=").append(uncompressedSizeWithoutHeader)
.append(", prevBlockOffset=").append(prevBlockOffset)
.append(", isUseHBaseChecksum=").append(fileContext.isUseHBaseChecksum());
if (fileContext.isUseHBaseChecksum()) {
sb.append(", checksumType=").append(ChecksumType.codeToType(this.buf.get(24)))
.append(", bytesPerChecksum=").append(this.buf.getInt(24 + 1))
.append(", onDiskDataSizeWithHeader=").append(onDiskDataSizeWithHeader);
} else {
sb.append(", onDiskDataSizeWithHeader=").append(onDiskDataSizeWithHeader)
.append("(").append(onDiskSizeWithoutHeader)
.append("+").append(HConstants.HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM).append(")");
}
String dataBegin = null;
if (buf.hasArray()) {
dataBegin = Bytes.toStringBinary(buf.array(), buf.arrayOffset() + headerSize(),
Math.min(32, buf.limit() - buf.arrayOffset() - headerSize()));
} else {
ByteBuffer bufWithoutHeader = getBufferWithoutHeader();
byte[] dataBeginBytes = new byte[Math.min(32,
bufWithoutHeader.limit() - bufWithoutHeader.position())];
bufWithoutHeader.get(dataBeginBytes);
dataBegin = Bytes.toStringBinary(dataBeginBytes);
}
sb.append(", getOnDiskSizeWithHeader=").append(getOnDiskSizeWithHeader())
.append(", totalChecksumBytes=").append(totalChecksumBytes())
.append(", isUnpacked=").append(isUnpacked())
.append(", buf=[").append(buf).append("]")
.append(", dataBeginsWith=").append(dataBegin)
.append(", fileContext=").append(fileContext)
.append("]");
return sb.toString();
}
/**
* Retrieves the decompressed/decrypted view of this block. An encoded block remains in its
* encoded structure. Internal structures are shared between instances where applicable.
*/
HFileBlock unpack(HFileContext fileContext, FSReader reader) throws IOException {
if (!fileContext.isCompressedOrEncrypted()) {
// TODO: cannot use our own fileContext here because HFileBlock(ByteBuffer, boolean),
// which is used for block serialization to L2 cache, does not preserve encoding and
// encryption details.
return this;
}
HFileBlock unpacked = new HFileBlock(this);
unpacked.allocateBuffer(); // allocates space for the decompressed block
HFileBlockDecodingContext ctx = blockType == BlockType.ENCODED_DATA ?
reader.getBlockDecodingContext() : reader.getDefaultBlockDecodingContext();
ByteBuffer dup = this.buf.duplicate();
dup.position(this.headerSize());
dup = dup.slice();
ctx.prepareDecoding(unpacked.getOnDiskSizeWithoutHeader(),
unpacked.getUncompressedSizeWithoutHeader(), unpacked.getBufferWithoutHeader(),
dup);
return unpacked;
}
/**
* Always allocates a new buffer of the correct size. Copies header bytes
* from the existing buffer. Does not change header fields.
* Reserve room to keep checksum bytes too.
*/
private void allocateBuffer() {
int cksumBytes = totalChecksumBytes();
int headerSize = headerSize();
int capacityNeeded = headerSize + uncompressedSizeWithoutHeader + cksumBytes;
// TODO we need consider allocating offheap here?
ByteBuffer newBuf = ByteBuffer.allocate(capacityNeeded);
// Copy header bytes into newBuf.
// newBuf is HBB so no issue in calling array()
ByteBuffer dup = buf.duplicate();
dup.position(0);
dup.get(newBuf.array(), newBuf.arrayOffset(), headerSize);
buf = newBuf;
// set limit to exclude next block's header
buf.limit(headerSize + uncompressedSizeWithoutHeader + cksumBytes);
}
/**
* Return true when this block's buffer has been unpacked, false otherwise. Note this is a
* calculated heuristic, not tracked attribute of the block.
*/
public boolean isUnpacked() {
final int cksumBytes = totalChecksumBytes();
final int headerSize = headerSize();
final int expectedCapacity = headerSize + uncompressedSizeWithoutHeader + cksumBytes;
final int bufCapacity = buf.capacity();
return bufCapacity == expectedCapacity || bufCapacity == expectedCapacity + headerSize;
}
/** An additional sanity-check in case no compression or encryption is being used. */
public void sanityCheckUncompressedSize() throws IOException {
if (onDiskSizeWithoutHeader != uncompressedSizeWithoutHeader + totalChecksumBytes()) {
throw new IOException("Using no compression but "
+ "onDiskSizeWithoutHeader=" + onDiskSizeWithoutHeader + ", "
+ "uncompressedSizeWithoutHeader=" + uncompressedSizeWithoutHeader
+ ", numChecksumbytes=" + totalChecksumBytes());
}
}
/**
* Cannot be {@link #UNSET}. Must be a legitimate value. Used re-making the {@link CacheKey} when
* block is returned to the cache.
* @return the offset of this block in the file it was read from
*/
long getOffset() {
if (offset < 0) {
throw new IllegalStateException("HFile block offset not initialized properly");
}
return offset;
}
/**
* @return a byte stream reading the data + checksum of this block
*/
public DataInputStream getByteStream() {
ByteBuffer dup = this.buf.duplicate();
dup.position(this.headerSize());
return new DataInputStream(new ByteBufferInputStream(dup));
}
@Override
public long heapSize() {
long size = ClassSize.align(
ClassSize.OBJECT +
// Block type, byte buffer and meta references
3 * ClassSize.REFERENCE +
// On-disk size, uncompressed size, and next block's on-disk size
// bytePerChecksum and onDiskDataSize
4 * Bytes.SIZEOF_INT +
// This and previous block offset
2 * Bytes.SIZEOF_LONG +
// Heap size of the meta object. meta will be always not null.
fileContext.heapSize()
);
if (buf != null) {
// Deep overhead of the byte buffer. Needs to be aligned separately.
size += ClassSize.align(buf.capacity() + BYTE_BUFFER_HEAP_SIZE);
}
return ClassSize.align(size);
}
/**
* Read from an input stream at least necessaryLen and if possible,
* extraLen also if available. Analogous to
* {@link IOUtils#readFully(InputStream, byte[], int, int)}, but specifies a
* number of "extra" bytes to also optionally read.
*
* @param in the input stream to read from
* @param buf the buffer to read into
* @param bufOffset the destination offset in the buffer
* @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
* @return true if succeeded reading the extra bytes
* @throws IOException if failed to read the necessary bytes
*/
static boolean readWithExtra(InputStream in, byte[] buf,
int bufOffset, int necessaryLen, int extraLen) throws IOException {
int bytesRemaining = necessaryLen + extraLen;
while (bytesRemaining > 0) {
int ret = in.read(buf, bufOffset, bytesRemaining);
if (ret == -1 && bytesRemaining <= extraLen) {
// We could not read the "extra data", but that is OK.
break;
}
if (ret < 0) {
throw new IOException("Premature EOF from inputStream (read "
+ "returned " + ret + ", was trying to read " + necessaryLen
+ " necessary bytes and " + extraLen + " extra bytes, "
+ "successfully read "
+ (necessaryLen + extraLen - bytesRemaining));
}
bufOffset += ret;
bytesRemaining -= ret;
}
return bytesRemaining <= 0;
}
/**
* Read from an input stream at least necessaryLen and if possible,
* extraLen 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.
*
* @param in the input stream to read from
* @param position the position within the stream from which to start reading
* @param buf the buffer to read into
* @param bufOffset the destination offset in the buffer
* @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
* @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
*/
@VisibleForTesting
static boolean positionalReadWithExtra(FSDataInputStream in,
long position, byte[] buf, int bufOffset, int necessaryLen, int extraLen)
throws IOException {
int bytesRemaining = necessaryLen + extraLen;
int bytesRead = 0;
while (bytesRead < necessaryLen) {
int ret = in.read(position, buf, bufOffset, bytesRemaining);
if (ret < 0) {
throw new IOException("Premature EOF from inputStream (positional read "
+ "returned " + ret + ", was trying to read " + necessaryLen
+ " necessary bytes and " + extraLen + " extra bytes, "
+ "successfully read " + bytesRead);
}
position += ret;
bufOffset += ret;
bytesRemaining -= ret;
bytesRead += ret;
}
return bytesRead != necessaryLen && bytesRemaining <= 0;
}
/**
* Unified version 2 {@link HFile} block writer. The intended usage pattern
* is as follows:
*
* - Construct an {@link HFileBlock.Writer}, providing a compression algorithm.
*
- Call {@link Writer#startWriting} and get a data stream to write to.
*
- Write your data into the stream.
*
- Call Writer#writeHeaderAndData(FSDataOutputStream) as many times as you need to.
* store the serialized block into an external stream.
*
- Repeat to write more blocks.
*
*
*/
public static class Writer {
private enum State {
INIT,
WRITING,
BLOCK_READY
};
/** Writer state. Used to ensure the correct usage protocol. */
private State state = State.INIT;
/** Data block encoder used for data blocks */
private final HFileDataBlockEncoder dataBlockEncoder;
private HFileBlockEncodingContext dataBlockEncodingCtx;
/** block encoding context for non-data blocks*/
private HFileBlockDefaultEncodingContext defaultBlockEncodingCtx;
/**
* The stream we use to accumulate data into a block in an uncompressed format.
* We reset this stream at the end of each block and reuse it. The
* header is written as the first {@link HConstants#HFILEBLOCK_HEADER_SIZE} bytes into this
* stream.
*/
private ByteArrayOutputStream baosInMemory;
/**
* Current block type. Set in {@link #startWriting(BlockType)}. Could be
* changed in {@link #finishBlock()} from {@link BlockType#DATA}
* to {@link BlockType#ENCODED_DATA}.
*/
private BlockType blockType;
/**
* A stream that we write uncompressed bytes to, which compresses them and
* writes them to {@link #baosInMemory}.
*/
private DataOutputStream userDataStream;
// Size of actual data being written. Not considering the block encoding/compression. This
// includes the header size also.
private int unencodedDataSizeWritten;
// Size of actual data being written. considering the block encoding. This
// includes the header size also.
private int encodedDataSizeWritten;
/**
* Bytes to be written to the file system, including the header. Compressed
* if compression is turned on. It also includes the checksum data that
* immediately follows the block data. (header + data + checksums)
*/
private ByteArrayOutputStream onDiskBlockBytesWithHeader;
/**
* The size of the checksum data on disk. It is used only if data is
* not compressed. If data is compressed, then the checksums are already
* part of onDiskBytesWithHeader. If data is uncompressed, then this
* variable stores the checksum data for this block.
*/
private byte[] onDiskChecksum = HConstants.EMPTY_BYTE_ARRAY;
/**
* Current block's start offset in the {@link HFile}. Set in
* {@link #writeHeaderAndData(FSDataOutputStream)}.
*/
private long startOffset;
/**
* Offset of previous block by block type. Updated when the next block is
* started.
*/
private long[] prevOffsetByType;
/** The offset of the previous block of the same type */
private long prevOffset;
/** Meta data that holds information about the hfileblock**/
private HFileContext fileContext;
/**
* @param dataBlockEncoder data block encoding algorithm to use
*/
public Writer(HFileDataBlockEncoder dataBlockEncoder, HFileContext fileContext) {
if (fileContext.getBytesPerChecksum() < HConstants.HFILEBLOCK_HEADER_SIZE) {
throw new RuntimeException("Unsupported value of bytesPerChecksum. " +
" Minimum is " + HConstants.HFILEBLOCK_HEADER_SIZE + " but the configured value is " +
fileContext.getBytesPerChecksum());
}
this.dataBlockEncoder = dataBlockEncoder != null?
dataBlockEncoder: NoOpDataBlockEncoder.INSTANCE;
this.dataBlockEncodingCtx = this.dataBlockEncoder.
newDataBlockEncodingContext(HConstants.HFILEBLOCK_DUMMY_HEADER, fileContext);
// TODO: This should be lazily instantiated since we usually do NOT need this default encoder
this.defaultBlockEncodingCtx = new HFileBlockDefaultEncodingContext(null,
HConstants.HFILEBLOCK_DUMMY_HEADER, fileContext);
// TODO: Set BAOS initial size. Use fileContext.getBlocksize() and add for header/checksum
baosInMemory = new ByteArrayOutputStream();
prevOffsetByType = new long[BlockType.values().length];
for (int i = 0; i < prevOffsetByType.length; ++i) {
prevOffsetByType[i] = UNSET;
}
// TODO: Why fileContext saved away when we have dataBlockEncoder and/or
// defaultDataBlockEncoder?
this.fileContext = fileContext;
}
/**
* Starts writing into the block. The previous block's data is discarded.
*
* @return the stream the user can write their data into
* @throws IOException
*/
DataOutputStream startWriting(BlockType newBlockType)
throws IOException {
if (state == State.BLOCK_READY && startOffset != -1) {
// We had a previous block that was written to a stream at a specific
// offset. Save that offset as the last offset of a block of that type.
prevOffsetByType[blockType.getId()] = startOffset;
}
startOffset = -1;
blockType = newBlockType;
baosInMemory.reset();
baosInMemory.write(HConstants.HFILEBLOCK_DUMMY_HEADER);
state = State.WRITING;
// We will compress it later in finishBlock()
userDataStream = new DataOutputStream(baosInMemory);
if (newBlockType == BlockType.DATA) {
this.dataBlockEncoder.startBlockEncoding(dataBlockEncodingCtx, userDataStream);
}
this.unencodedDataSizeWritten = 0;
this.encodedDataSizeWritten = 0;
return userDataStream;
}
/**
* Writes the Cell to this block
* @param cell
* @throws IOException
*/
void write(Cell cell) throws IOException{
expectState(State.WRITING);
int posBeforeEncode = this.userDataStream.size();
this.unencodedDataSizeWritten +=
this.dataBlockEncoder.encode(cell, dataBlockEncodingCtx, this.userDataStream);
this.encodedDataSizeWritten += this.userDataStream.size() - posBeforeEncode;
}
/**
* Returns the stream for the user to write to. The block writer takes care
* of handling compression and buffering for caching on write. Can only be
* called in the "writing" state.
*
* @return the data output stream for the user to write to
*/
DataOutputStream getUserDataStream() {
expectState(State.WRITING);
return userDataStream;
}
/**
* Transitions the block writer from the "writing" state to the "block
* ready" state. Does nothing if a block is already finished.
*/
void ensureBlockReady() throws IOException {
Preconditions.checkState(state != State.INIT,
"Unexpected state: " + state);
if (state == State.BLOCK_READY) {
return;
}
// This will set state to BLOCK_READY.
finishBlock();
}
/**
* Finish up writing of the block.
* Flushes the compressing stream (if using compression), fills out the header,
* does any compression/encryption of bytes to flush out to disk, and manages
* the cache on write content, if applicable. Sets block write state to "block ready".
*/
private void finishBlock() throws IOException {
if (blockType == BlockType.DATA) {
this.dataBlockEncoder.endBlockEncoding(dataBlockEncodingCtx, userDataStream,
baosInMemory.getBuffer(), blockType);
blockType = dataBlockEncodingCtx.getBlockType();
}
userDataStream.flush();
prevOffset = prevOffsetByType[blockType.getId()];
// We need to set state before we can package the block up for cache-on-write. In a way, the
// block is ready, but not yet encoded or compressed.
state = State.BLOCK_READY;
Bytes compressAndEncryptDat;
if (blockType == BlockType.DATA || blockType == BlockType.ENCODED_DATA) {
compressAndEncryptDat = dataBlockEncodingCtx.
compressAndEncrypt(baosInMemory.getBuffer(),
0, baosInMemory.size());
} else {
compressAndEncryptDat = defaultBlockEncodingCtx.
compressAndEncrypt(baosInMemory.getBuffer(),
0, baosInMemory.size());
}
if (compressAndEncryptDat == null) {
compressAndEncryptDat = new Bytes(baosInMemory.getBuffer(),
0, baosInMemory.size());
}
if (onDiskBlockBytesWithHeader == null) {
onDiskBlockBytesWithHeader = new ByteArrayOutputStream(compressAndEncryptDat.getLength());
}
onDiskBlockBytesWithHeader.reset();
onDiskBlockBytesWithHeader.write(compressAndEncryptDat.get(),
compressAndEncryptDat.getOffset(), compressAndEncryptDat.getLength());
// Calculate how many bytes we need for checksum on the tail of the block.
int numBytes = (int) ChecksumUtil.numBytes(
onDiskBlockBytesWithHeader.size(),
fileContext.getBytesPerChecksum());
// Put the header for the on disk bytes; header currently is unfilled-out
putHeader(onDiskBlockBytesWithHeader,
onDiskBlockBytesWithHeader.size() + numBytes,
baosInMemory.size(), onDiskBlockBytesWithHeader.size());
// Set the header for the uncompressed bytes (for cache-on-write)
if (onDiskChecksum.length != numBytes) {
onDiskChecksum = new byte[numBytes];
}
ChecksumUtil.generateChecksums(
onDiskBlockBytesWithHeader.getBuffer(), 0,onDiskBlockBytesWithHeader.size(),
onDiskChecksum, 0, fileContext.getChecksumType(), fileContext.getBytesPerChecksum());
}
private void putHeader(ByteArrayOutputStream dest, int onDiskSize,
int uncompressedSize, int onDiskDataSize) {
putHeader(dest.getBuffer(),0, onDiskSize, uncompressedSize, onDiskDataSize);
}
/**
* Put the header into the given byte array at the given offset.
* @param onDiskSize size of the block on disk header + data + checksum
* @param uncompressedSize size of the block after decompression (but
* before optional data block decoding) including header
* @param onDiskDataSize size of the block on disk with header
* and data but not including the checksums
*/
private void putHeader(byte[] dest, int offset, int onDiskSize,
int uncompressedSize, int onDiskDataSize) {
offset = blockType.put(dest, offset);
offset = Bytes.putInt(dest, offset, onDiskSize - HConstants.HFILEBLOCK_HEADER_SIZE);
offset = Bytes.putInt(dest, offset, uncompressedSize - HConstants.HFILEBLOCK_HEADER_SIZE);
offset = Bytes.putLong(dest, offset, prevOffset);
offset = Bytes.putByte(dest, offset, fileContext.getChecksumType().getCode());
offset = Bytes.putInt(dest, offset, fileContext.getBytesPerChecksum());
Bytes.putInt(dest, offset, onDiskDataSize);
}
/**
* Similar to {@link #writeHeaderAndData(FSDataOutputStream)}, but records
* the offset of this block so that it can be referenced in the next block
* of the same type.
*
* @param out
* @throws IOException
*/
void writeHeaderAndData(FSDataOutputStream out) throws IOException {
long offset = out.getPos();
if (startOffset != UNSET && offset != startOffset) {
throw new IOException("A " + blockType + " block written to a "
+ "stream twice, first at offset " + startOffset + ", then at "
+ offset);
}
startOffset = offset;
finishBlockAndWriteHeaderAndData((DataOutputStream) out);
}
/**
* Writes the header and the compressed data of this block (or uncompressed
* data when not using compression) into the given stream. Can be called in
* the "writing" state or in the "block ready" state. If called in the
* "writing" state, transitions the writer to the "block ready" state.
*
* @param out the output stream to write the
* @throws IOException
*/
protected void finishBlockAndWriteHeaderAndData(DataOutputStream out)
throws IOException {
ensureBlockReady();
long startTime = System.currentTimeMillis();
out.write(onDiskBlockBytesWithHeader.getBuffer(), 0, onDiskBlockBytesWithHeader.size());
out.write(onDiskChecksum);
HFile.updateWriteLatency(System.currentTimeMillis() - startTime);
}
/**
* Returns the header or the compressed data (or uncompressed data when not
* using compression) as a byte array. Can be called in the "writing" state
* or in the "block ready" state. If called in the "writing" state,
* transitions the writer to the "block ready" state. This returns
* the header + data + checksums stored on disk.
*
* @return header and data as they would be stored on disk in a byte array
* @throws IOException
*/
byte[] getHeaderAndDataForTest() throws IOException {
ensureBlockReady();
// This is not very optimal, because we are doing an extra copy.
// But this method is used only by unit tests.
byte[] output =
new byte[onDiskBlockBytesWithHeader.size()
+ onDiskChecksum.length];
System.arraycopy(onDiskBlockBytesWithHeader.getBuffer(), 0, output, 0,
onDiskBlockBytesWithHeader.size());
System.arraycopy(onDiskChecksum, 0, output,
onDiskBlockBytesWithHeader.size(), onDiskChecksum.length);
return output;
}
/**
* Releases resources used by this writer.
*/
void release() {
if (dataBlockEncodingCtx != null) {
dataBlockEncodingCtx.close();
dataBlockEncodingCtx = null;
}
if (defaultBlockEncodingCtx != null) {
defaultBlockEncodingCtx.close();
defaultBlockEncodingCtx = null;
}
}
/**
* Returns the on-disk size of the data portion of the block. This is the
* compressed size if compression is enabled. Can only be called in the
* "block ready" state. Header is not compressed, and its size is not
* included in the return value.
*
* @return the on-disk size of the block, not including the header.
*/
int getOnDiskSizeWithoutHeader() {
expectState(State.BLOCK_READY);
return onDiskBlockBytesWithHeader.size() +
onDiskChecksum.length - HConstants.HFILEBLOCK_HEADER_SIZE;
}
/**
* Returns the on-disk size of the block. Can only be called in the
* "block ready" state.
*
* @return the on-disk size of the block ready to be written, including the
* header size, the data and the checksum data.
*/
int getOnDiskSizeWithHeader() {
expectState(State.BLOCK_READY);
return onDiskBlockBytesWithHeader.size() + onDiskChecksum.length;
}
/**
* The uncompressed size of the block data. Does not include header size.
*/
int getUncompressedSizeWithoutHeader() {
expectState(State.BLOCK_READY);
return baosInMemory.size() - HConstants.HFILEBLOCK_HEADER_SIZE;
}
/**
* The uncompressed size of the block data, including header size.
*/
int getUncompressedSizeWithHeader() {
expectState(State.BLOCK_READY);
return baosInMemory.size();
}
/** @return true if a block is being written */
boolean isWriting() {
return state == State.WRITING;
}
/**
* Returns the number of bytes written into the current block so far, or
* zero if not writing the block at the moment. Note that this will return
* zero in the "block ready" state as well.
*
* @return the number of bytes written
*/
public int encodedBlockSizeWritten() {
if (state != State.WRITING)
return 0;
return this.encodedDataSizeWritten;
}
/**
* Returns the number of bytes written into the current block so far, or
* zero if not writing the block at the moment. Note that this will return
* zero in the "block ready" state as well.
*
* @return the number of bytes written
*/
int blockSizeWritten() {
if (state != State.WRITING) return 0;
return this.unencodedDataSizeWritten;
}
/**
* Clones the header followed by the uncompressed data, even if using
* compression. This is needed for storing uncompressed blocks in the block
* cache. Can be called in the "writing" state or the "block ready" state.
* Returns only the header and data, does not include checksum data.
*
* @return Returns a copy of uncompressed block bytes for caching on write
*/
@VisibleForTesting
ByteBuffer cloneUncompressedBufferWithHeader() {
expectState(State.BLOCK_READY);
byte[] uncompressedBlockBytesWithHeader = baosInMemory.toByteArray();
int numBytes = (int) ChecksumUtil.numBytes(
onDiskBlockBytesWithHeader.size(),
fileContext.getBytesPerChecksum());
putHeader(uncompressedBlockBytesWithHeader, 0,
onDiskBlockBytesWithHeader.size() + numBytes,
uncompressedBlockBytesWithHeader.length, onDiskBlockBytesWithHeader.size());
return ByteBuffer.wrap(uncompressedBlockBytesWithHeader);
}
/**
* Clones the header followed by the on-disk (compressed/encoded/encrypted) data. This is
* needed for storing packed blocks in the block cache. Expects calling semantics identical to
* {@link #getUncompressedBufferWithHeader()}. Returns only the header and data,
* Does not include checksum data.
*
* @return Returns a copy of block bytes for caching on write
*/
private ByteBuffer cloneOnDiskBufferWithHeader() {
expectState(State.BLOCK_READY);
return ByteBuffer.wrap(onDiskBlockBytesWithHeader.toByteArray());
}
private void expectState(State expectedState) {
if (state != expectedState) {
throw new IllegalStateException("Expected state: " + expectedState +
", actual state: " + state);
}
}
/**
* Takes the given {@link BlockWritable} instance, creates a new block of
* its appropriate type, writes the writable into this block, and flushes
* the block into the output stream. The writer is instructed not to buffer
* uncompressed bytes for cache-on-write.
*
* @param bw the block-writable object to write as a block
* @param out the file system output stream
* @throws IOException
*/
void writeBlock(BlockWritable bw, FSDataOutputStream out)
throws IOException {
bw.writeToBlock(startWriting(bw.getBlockType()));
writeHeaderAndData(out);
}
/**
* Creates a new HFileBlock. Checksums have already been validated, so
* the byte buffer passed into the constructor of this newly created
* block does not have checksum data even though the header minor
* version is MINOR_VERSION_WITH_CHECKSUM. This is indicated by setting a
* 0 value in bytesPerChecksum. This method copies the on-disk or
* uncompressed data to build the HFileBlock which is used only
* while writing blocks and caching.
*
*
TODO: Should there be an option where a cache can ask that hbase preserve block
* checksums for checking after a block comes out of the cache? Otehrwise, cache is responsible
* for blocks being wholesome (ECC memory or if file-backed, it does checksumming).
*/
HFileBlock getBlockForCaching(CacheConfig cacheConf) {
HFileContext newContext = new HFileContextBuilder()
.withBlockSize(fileContext.getBlocksize())
.withBytesPerCheckSum(0)
.withChecksumType(ChecksumType.NULL) // no checksums in cached data
.withCompression(fileContext.getCompression())
.withDataBlockEncoding(fileContext.getDataBlockEncoding())
.withHBaseCheckSum(fileContext.isUseHBaseChecksum())
.withCompressTags(fileContext.isCompressTags())
.withIncludesMvcc(fileContext.isIncludesMvcc())
.withIncludesTags(fileContext.isIncludesTags())
.build();
return new HFileBlock(blockType, getOnDiskSizeWithoutHeader(),
getUncompressedSizeWithoutHeader(), prevOffset,
cacheConf.shouldCacheCompressed(blockType.getCategory())?
cloneOnDiskBufferWithHeader() :
cloneUncompressedBufferWithHeader(),
FILL_HEADER, startOffset, UNSET,
onDiskBlockBytesWithHeader.size() + onDiskChecksum.length, newContext);
}
}
/** Something that can be written into a block. */
interface BlockWritable {
/** The type of block this data should use. */
BlockType getBlockType();
/**
* Writes the block to the provided stream. Must not write any magic
* records.
*
* @param out a stream to write uncompressed data into
*/
void writeToBlock(DataOutput out) throws IOException;
}
// Block readers and writers
/** An interface allowing to iterate {@link HFileBlock}s. */
interface BlockIterator {
/**
* Get the next block, or null if there are no more blocks to iterate.
*/
HFileBlock nextBlock() throws IOException;
/**
* Similar to {@link #nextBlock()} but checks block type, throws an
* exception if incorrect, and returns the HFile block
*/
HFileBlock nextBlockWithBlockType(BlockType blockType) throws IOException;
}
/** A full-fledged reader with iteration ability. */
interface FSReader {
/**
* Reads the block at the given offset in the file with the given on-disk
* size and uncompressed size.
*
* @param offset
* @param onDiskSize the on-disk size of the entire block, including all
* applicable headers, or -1 if unknown
* @return the newly read block
*/
HFileBlock readBlockData(long offset, long onDiskSize, boolean pread, boolean updateMetrics)
throws IOException;
/**
* Creates a block iterator over the given portion of the {@link HFile}.
* The iterator returns blocks starting with offset such that offset <=
* startOffset < endOffset. Returned blocks are always unpacked.
*
* @param startOffset the offset of the block to start iteration with
* @param endOffset the offset to end iteration at (exclusive)
* @return an iterator of blocks between the two given offsets
*/
BlockIterator blockRange(long startOffset, long endOffset);
/** Closes the backing streams */
void closeStreams() throws IOException;
/** Get a decoder for {@link BlockType#ENCODED_DATA} blocks from this file. */
HFileBlockDecodingContext getBlockDecodingContext();
/** Get the default decoder for blocks from this file. */
HFileBlockDecodingContext getDefaultBlockDecodingContext();
/**
* To close the stream's socket. Note: This can be concurrently called from multiple threads and
* implementation should take care of thread safety.
*/
void unbufferStream();
}
/**
* A common implementation of some methods of {@link FSReader} and some
* tools for implementing HFile format version-specific block readers.
*/
private abstract static class AbstractFSReader implements FSReader {
/** Compression algorithm used by the {@link HFile} */
/** The size of the file we are reading from, or -1 if unknown. */
protected long fileSize;
/** The size of the header */
protected final int hdrSize;
/** The filesystem used to access data */
protected HFileSystem hfs;
protected final Lock streamLock = new ReentrantLock();
/** The default buffer size for our buffered streams */
public static final int DEFAULT_BUFFER_SIZE = 1 << 20;
protected HFileContext fileContext;
// Cache the fileName
protected String pathName;
public AbstractFSReader(long fileSize, HFileSystem hfs, Path path, HFileContext fileContext)
throws IOException {
this.fileSize = fileSize;
this.hfs = hfs;
if (path != null) {
this.pathName = path.toString();
}
this.fileContext = fileContext;
this.hdrSize = headerSize(fileContext.isUseHBaseChecksum());
}
@Override
public BlockIterator blockRange(final long startOffset,
final long endOffset) {
final FSReader owner = this; // handle for inner class
return new BlockIterator() {
private long offset = startOffset;
// Cache length of next block. Current block has the length of next block in it.
private long length = -1;
@Override
public HFileBlock nextBlock() throws IOException {
if (offset >= endOffset) {
return null;
}
HFileBlock b = readBlockData(offset, length, false, false);
offset += b.getOnDiskSizeWithHeader();
length = b.getNextBlockOnDiskSize();
return b.unpack(fileContext, owner);
}
@Override
public HFileBlock nextBlockWithBlockType(BlockType blockType)
throws IOException {
HFileBlock blk = nextBlock();
if (blk.getBlockType() != blockType) {
throw new IOException("Expected block of type " + blockType
+ " but found " + blk.getBlockType());
}
return blk;
}
};
}
/**
* Does a positional read or a seek and read into the given buffer. Returns
* the on-disk size of the next block, or -1 if it could not be read/determined; e.g. EOF.
*
* @param dest destination buffer
* @param destOffset offset into the destination buffer at where to put the bytes we read
* @param size size of read
* @param peekIntoNextBlock whether to read the next block's on-disk size
* @param fileOffset position in the stream to read at
* @param pread whether we should do a positional read
* @param istream The input source of data
* @return the on-disk size of the next block with header size included, or
* -1 if it could not be determined; if not -1, the dest INCLUDES the
* next header
* @throws IOException
*/
protected int readAtOffset(FSDataInputStream istream, byte [] dest, int destOffset, int size,
boolean peekIntoNextBlock, long fileOffset, boolean pread) throws IOException {
if (peekIntoNextBlock && destOffset + size + hdrSize > dest.length) {
// We are asked to read the next block's header as well, but there is
// not enough room in the array.
throw new IOException("Attempted to read " + size + " bytes and " +
hdrSize + " bytes of next header into a " + dest.length +
"-byte array at offset " + destOffset);
}
if (!pread && streamLock.tryLock()) {
// Seek + read. Better for scanning.
try {
HFileUtil.seekOnMultipleSources(istream, fileOffset);
// TODO: do we need seek time latencies?
long realOffset = istream.getPos();
if (realOffset != fileOffset) {
throw new IOException("Tried to seek to " + fileOffset + " to "
+ "read " + size + " bytes, but pos=" + realOffset
+ " after seek");
}
if (!peekIntoNextBlock) {
IOUtils.readFully(istream, dest, destOffset, size);
return -1;
}
// Try to read the next block header.
if (!readWithExtra(istream, dest, destOffset, size, hdrSize)) {
return -1;
}
} finally {
streamLock.unlock();
}
} else {
// Positional read. Better for random reads; or when the streamLock is already locked.
int extraSize = peekIntoNextBlock ? hdrSize : 0;
if (!positionalReadWithExtra(istream, fileOffset, dest, destOffset, size, extraSize)) {
return -1;
}
}
assert peekIntoNextBlock;
return Bytes.toInt(dest, destOffset + size + BlockType.MAGIC_LENGTH) + hdrSize;
}
}
/**
* Data-structure to use caching the header of the NEXT block. Only works if next read
* that comes in here is next in sequence in this block.
*
* When we read, we read current block and the next blocks' header. We do this so we have
* the length of the next block to read if the hfile index is not available (rare).
* TODO: Review!! This trick of reading next blocks header is a pain, complicates our
* read path and I don't think it needed given it rare we don't have the block index
* (it is 'normally' present, gotten from the hfile index). FIX!!!
*/
private static class PrefetchedHeader {
long offset = -1;
byte [] header = new byte[HConstants.HFILEBLOCK_HEADER_SIZE];
final ByteBuffer buf = ByteBuffer.wrap(header, 0, HConstants.HFILEBLOCK_HEADER_SIZE);
@Override
public String toString() {
return "offset=" + this.offset + ", header=" + Bytes.toStringBinary(header);
}
}
/**
* Reads version 2 blocks from the filesystem.
*/
static class FSReaderImpl extends AbstractFSReader {
/** The file system stream of the underlying {@link HFile} that
* does or doesn't do checksum validations in the filesystem */
protected FSDataInputStreamWrapper streamWrapper;
private HFileBlockDecodingContext encodedBlockDecodingCtx;
/** Default context used when BlockType != {@link BlockType#ENCODED_DATA}. */
private final HFileBlockDefaultDecodingContext defaultDecodingCtx;
/**
* Cache of the NEXT header after this. Check it is indeed next blocks header
* before using it. TODO: Review. This overread into next block to fetch
* next blocks header seems unnecessary given we usually get the block size
* from the hfile index. Review!
*/
private AtomicReference prefetchedHeader =
new AtomicReference(new PrefetchedHeader());
public FSReaderImpl(FSDataInputStreamWrapper stream, long fileSize, HFileSystem hfs, Path path,
HFileContext fileContext) throws IOException {
super(fileSize, hfs, path, fileContext);
this.streamWrapper = stream;
// Older versions of HBase didn't support checksum.
this.streamWrapper.prepareForBlockReader(!fileContext.isUseHBaseChecksum());
defaultDecodingCtx = new HFileBlockDefaultDecodingContext(fileContext);
encodedBlockDecodingCtx = defaultDecodingCtx;
}
/**
* A constructor that reads files with the latest minor version.
* This is used by unit tests only.
*/
FSReaderImpl(FSDataInputStream istream, long fileSize, HFileContext fileContext)
throws IOException {
this(new FSDataInputStreamWrapper(istream), fileSize, null, null, fileContext);
}
/**
* Reads a version 2 block (version 1 blocks not supported and not expected). Tries to do as
* little memory allocation as possible, using the provided on-disk size.
*
* @param offset the offset in the stream to read at
* @param onDiskSizeWithHeaderL the on-disk size of the block, including
* the header, or -1 if unknown; i.e. when iterating over blocks reading
* in the file metadata info.
* @param pread whether to use a positional read
*/
@Override
public HFileBlock readBlockData(long offset, long onDiskSizeWithHeaderL, boolean pread,
boolean updateMetrics) throws IOException {
// Get a copy of the current state of whether to validate
// hbase checksums or not for this read call. This is not
// thread-safe but the one constaint is that if we decide
// to skip hbase checksum verification then we are
// guaranteed to use hdfs checksum verification.
boolean doVerificationThruHBaseChecksum = streamWrapper.shouldUseHBaseChecksum();
FSDataInputStream is = streamWrapper.getStream(doVerificationThruHBaseChecksum);
HFileBlock blk = readBlockDataInternal(is, offset,
onDiskSizeWithHeaderL, pread,
doVerificationThruHBaseChecksum, updateMetrics);
if (blk == null) {
HFile.LOG.warn("HBase checksum verification failed for file " +
pathName + " at offset " +
offset + " filesize " + fileSize +
". Retrying read with HDFS checksums turned on...");
if (!doVerificationThruHBaseChecksum) {
String msg = "HBase checksum verification failed for file " +
pathName + " at offset " +
offset + " filesize " + fileSize +
" but this cannot happen because doVerify is " +
doVerificationThruHBaseChecksum;
HFile.LOG.warn(msg);
throw new IOException(msg); // cannot happen case here
}
HFile.CHECKSUM_FAILURES.increment(); // update metrics
// If we have a checksum failure, we fall back into a mode where
// the next few reads use HDFS level checksums. We aim to make the
// next CHECKSUM_VERIFICATION_NUM_IO_THRESHOLD reads avoid
// hbase checksum verification, but since this value is set without
// holding any locks, it can so happen that we might actually do
// a few more than precisely this number.
is = this.streamWrapper.fallbackToFsChecksum(CHECKSUM_VERIFICATION_NUM_IO_THRESHOLD);
doVerificationThruHBaseChecksum = false;
blk = readBlockDataInternal(is, offset, onDiskSizeWithHeaderL, pread,
doVerificationThruHBaseChecksum, updateMetrics);
if (blk != null) {
HFile.LOG.warn("HDFS checksum verification succeeded for file " +
pathName + " at offset " +
offset + " filesize " + fileSize);
}
}
if (blk == null && !doVerificationThruHBaseChecksum) {
String msg = "readBlockData failed, possibly due to " +
"checksum verification failed for file " + pathName +
" at offset " + offset + " filesize " + fileSize;
HFile.LOG.warn(msg);
throw new IOException(msg);
}
// If there is a checksum mismatch earlier, then retry with
// HBase checksums switched off and use HDFS checksum verification.
// This triggers HDFS to detect and fix corrupt replicas. The
// next checksumOffCount read requests will use HDFS checksums.
// The decrementing of this.checksumOffCount is not thread-safe,
// but it is harmless because eventually checksumOffCount will be
// a negative number.
streamWrapper.checksumOk();
return blk;
}
/**
* @return Check onDiskSizeWithHeaderL size is healthy and then return it as an int
* @throws IOException
*/
private static int checkAndGetSizeAsInt(final long onDiskSizeWithHeaderL, final int hdrSize)
throws IOException {
if ((onDiskSizeWithHeaderL < hdrSize && onDiskSizeWithHeaderL != -1)
|| onDiskSizeWithHeaderL >= Integer.MAX_VALUE) {
throw new IOException("Invalid onDisksize=" + onDiskSizeWithHeaderL
+ ": expected to be at least " + hdrSize
+ " and at most " + Integer.MAX_VALUE + ", or -1");
}
return (int)onDiskSizeWithHeaderL;
}
/**
* Check atomic reference cache for this block's header. Cache only good if next
* read coming through is next in sequence in the block. We read next block's
* header on the tail of reading the previous block to save a seek. Otherwise,
* we have to do a seek to read the header before we can pull in the block OR
* we have to backup the stream because we over-read (the next block's header).
* @see PrefetchedHeader
* @return The cached block header or null if not found.
* @see #cacheNextBlockHeader(long, byte[], int, int)
*/
private ByteBuffer getCachedHeader(final long offset) {
PrefetchedHeader ph = this.prefetchedHeader.get();
return ph != null && ph.offset == offset? ph.buf: null;
}
/**
* Save away the next blocks header in atomic reference.
* @see #getCachedHeader(long)
* @see PrefetchedHeader
*/
private void cacheNextBlockHeader(final long offset,
final byte [] header, final int headerOffset, final int headerLength) {
PrefetchedHeader ph = new PrefetchedHeader();
ph.offset = offset;
System.arraycopy(header, headerOffset, ph.header, 0, headerLength);
this.prefetchedHeader.set(ph);
}
/**
* Verify the passed in onDiskSizeWithHeader aligns with what is in the header else something
* is not right.
* @throws IOException
*/
private void verifyOnDiskSizeMatchesHeader(final int passedIn, final ByteBuffer headerBuf,
final long offset, boolean verifyChecksum)
throws IOException {
// Assert size provided aligns with what is in the header
int fromHeader = getOnDiskSizeWithHeader(headerBuf, verifyChecksum);
if (passedIn != fromHeader) {
throw new IOException("Passed in onDiskSizeWithHeader=" + passedIn + " != " + fromHeader +
", offset=" + offset + ", fileContext=" + this.fileContext);
}
}
/**
* Reads a version 2 block.
*
* @param offset the offset in the stream to read at. Usually the
* @param onDiskSizeWithHeaderL the on-disk size of the block, including
* the header and checksums if present or -1 if unknown (as a long). Can be -1
* if we are doing raw iteration of blocks as when loading up file metadata; i.e.
* the first read of a new file (TODO: Fix! See HBASE-17072). Usually non-null gotten
* from the file index.
* @param pread whether to use a positional read
* @param verifyChecksum Whether to use HBase checksums.
* If HBase checksum is switched off, then use HDFS checksum.
* @return the HFileBlock or null if there is a HBase checksum mismatch
*/
protected HFileBlock readBlockDataInternal(FSDataInputStream is, long offset,
long onDiskSizeWithHeaderL, boolean pread, boolean verifyChecksum, boolean updateMetrics)
throws IOException {
if (offset < 0) {
throw new IOException("Invalid offset=" + offset + " trying to read "
+ "block (onDiskSize=" + onDiskSizeWithHeaderL + ")");
}
int onDiskSizeWithHeader = checkAndGetSizeAsInt(onDiskSizeWithHeaderL, hdrSize);
// Try and get cached header. Will serve us in rare case where onDiskSizeWithHeaderL is -1
// and will save us having to seek the stream backwards to reread the header we
// read the last time through here.
ByteBuffer headerBuf = getCachedHeader(offset);
if (LOG.isTraceEnabled()) {
LOG.trace("Reading " + this.fileContext.getHFileName() + " at offset=" + offset +
", pread=" + pread + ", verifyChecksum=" + verifyChecksum + ", cachedHeader=" +
headerBuf + ", onDiskSizeWithHeader=" + onDiskSizeWithHeader);
}
long startTime = System.currentTimeMillis();
if (onDiskSizeWithHeader <= 0) {
// We were not passed the block size. Need to get it from the header. If header was not in
// cache, need to seek to pull it in. This is costly and should happen very rarely.
// Currently happens on open of a hfile reader where we read the trailer blocks for
// indices. Otherwise, we are reading block sizes out of the hfile index. To check,
// enable TRACE in this file and you'll get an exception in a LOG every time we seek.
// See HBASE-17072 for more detail.
if (headerBuf == null) {
if (LOG.isTraceEnabled()) {
LOG.trace("Extra see to get block size!", new RuntimeException());
}
headerBuf = ByteBuffer.allocate(hdrSize);
readAtOffset(is, headerBuf.array(), headerBuf.arrayOffset(), hdrSize, false,
offset, pread);
}
onDiskSizeWithHeader = getOnDiskSizeWithHeader(headerBuf,
this.fileContext.isUseHBaseChecksum());
}
int preReadHeaderSize = headerBuf == null? 0 : hdrSize;
// Allocate enough space to fit the next block's header too; saves a seek next time through.
// onDiskBlock is whole block + header + checksums then extra hdrSize to read next header;
// onDiskSizeWithHeader is header, body, and any checksums if present. preReadHeaderSize
// says where to start reading. If we have the header cached, then we don't need to read
// it again and we can likely read from last place we left off w/o need to backup and reread
// the header we read last time through here. TODO: Review this overread of the header. Is it necessary
// when we get the block size from the hfile index? See note on PrefetchedHeader class above.
byte [] onDiskBlock = new byte[onDiskSizeWithHeader + hdrSize];
int nextBlockOnDiskSize = readAtOffset(is, onDiskBlock, preReadHeaderSize,
onDiskSizeWithHeader - preReadHeaderSize, true, offset + preReadHeaderSize, pread);
if (headerBuf != null) {
// The header has been read when reading the previous block OR in a distinct header-only
// read. Copy to this block's header.
System.arraycopy(headerBuf.array(), headerBuf.arrayOffset(), onDiskBlock, 0, hdrSize);
} else {
headerBuf = ByteBuffer.wrap(onDiskBlock, 0, hdrSize);
}
// Do a few checks before we go instantiate HFileBlock.
assert onDiskSizeWithHeader > this.hdrSize;
verifyOnDiskSizeMatchesHeader(onDiskSizeWithHeader, headerBuf, offset,
this.fileContext.isUseHBaseChecksum());
ByteBuffer onDiskBlockByteBuffer = ByteBuffer.wrap(onDiskBlock, 0, onDiskSizeWithHeader);
// Verify checksum of the data before using it for building HFileBlock.
if (verifyChecksum &&
!validateChecksum(offset, onDiskBlockByteBuffer, hdrSize)) {
return null;
}
long duration = System.currentTimeMillis() - startTime;
if (updateMetrics) {
HFile.updateReadLatency(duration, pread);
}
// 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(onDiskBlockByteBuffer, this.fileContext.isUseHBaseChecksum(), offset,
nextBlockOnDiskSize, fileContext);
// Run check on uncompressed sizings.
if (!fileContext.isCompressedOrEncrypted()) {
hFileBlock.sanityCheckUncompressed();
}
if (LOG.isTraceEnabled()) {
LOG.trace("Read " + hFileBlock + " in " + duration + " ns");
}
// Cache next block header if we read it for the next time through here.
if (nextBlockOnDiskSize != -1) {
cacheNextBlockHeader(offset + hFileBlock.getOnDiskSizeWithHeader(),
onDiskBlock, onDiskSizeWithHeader, hdrSize);
}
return hFileBlock;
}
void setIncludesMemstoreTS(boolean includesMemstoreTS) {
this.fileContext.setIncludesMvcc(includesMemstoreTS);
}
void setDataBlockEncoder(HFileDataBlockEncoder encoder) {
encodedBlockDecodingCtx = encoder.newDataBlockDecodingContext(this.fileContext);
}
@Override
public HFileBlockDecodingContext getBlockDecodingContext() {
return this.encodedBlockDecodingCtx;
}
@Override
public HFileBlockDecodingContext getDefaultBlockDecodingContext() {
return this.defaultDecodingCtx;
}
/**
* Generates the checksum for the header as well as the data and then validates it.
* If the block doesn't uses checksum, returns false.
* @return True if checksum matches, else false.
*/
protected boolean validateChecksum(long offset, ByteBuffer data, int hdrSize)
throws IOException {
// If this is an older version of the block that does not have checksums, then return false
// indicating that checksum verification did not succeed. Actually, this method should never
// be called when the minorVersion is 0, thus this is a defensive check for a cannot-happen
// case. Since this is a cannot-happen case, it is better to return false to indicate a
// checksum validation failure.
if (!fileContext.isUseHBaseChecksum()) {
return false;
}
return ChecksumUtil.validateChecksum(data, pathName, offset, hdrSize);
}
@Override
public void closeStreams() throws IOException {
streamWrapper.close();
}
@Override
public void unbufferStream() {
// To handle concurrent reads, ensure that no other client is accessing the streams while we
// unbuffer it.
if (streamLock.tryLock()) {
try {
this.streamWrapper.unbuffer();
} finally {
streamLock.unlock();
}
}
}
@Override
public String toString() {
return "hfs=" + hfs + ", path=" + pathName + ", fileContext=" + fileContext;
}
}
/** An additional sanity-check in case no compression or encryption is being used. */
void sanityCheckUncompressed() throws IOException {
if (onDiskSizeWithoutHeader != uncompressedSizeWithoutHeader +
totalChecksumBytes()) {
throw new IOException("Using no compression but "
+ "onDiskSizeWithoutHeader=" + onDiskSizeWithoutHeader + ", "
+ "uncompressedSizeWithoutHeader=" + uncompressedSizeWithoutHeader
+ ", numChecksumbytes=" + totalChecksumBytes());
}
}
// Cacheable implementation
@Override
public int getSerializedLength() {
if (buf != null) {
// Include extra bytes for block metadata.
return this.buf.limit() + BLOCK_METADATA_SPACE;
}
return 0;
}
// Cacheable implementation
@Override
public void serialize(ByteBuffer destination) {
// BE CAREFUL!! There is a custom version of this serialization over in BucketCache#doDrain.
// Make sure any changes in here are reflected over there.
ByteBufferUtils.copyFromBufferToBuffer(destination, this.buf, 0,
getSerializedLength() - BLOCK_METADATA_SPACE);
destination = addMetaData(destination);
// Make it ready for reading. flip sets position to zero and limit to current position which
// is what we want if we do not want to serialize the block plus checksums if present plus
// metadata.
destination.flip();
}
/**
* For use by bucketcache. This exposes internals.
*/
public ByteBuffer getMetaData() {
ByteBuffer bb = ByteBuffer.allocate(BLOCK_METADATA_SPACE);
bb = addMetaData(bb);
bb.flip();
return bb;
}
/**
* Adds metadata at current position (position is moved forward). Does not flip or reset.
* @return The passed destination with metadata added.
*/
private ByteBuffer addMetaData(final ByteBuffer destination) {
destination.put(this.fileContext.isUseHBaseChecksum() ? (byte) 1 : (byte) 0);
destination.putLong(this.offset);
destination.putInt(this.nextBlockOnDiskSize);
return destination;
}
// Cacheable implementation
@Override
public CacheableDeserializer getDeserializer() {
return HFileBlock.BLOCK_DESERIALIZER;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((blockType == null) ? 0 : blockType.hashCode());
result = prime * result + ((buf == null) ? 0 : buf.hashCode());
result = prime * result + ((fileContext == null) ? 0 : fileContext.hashCode());
result = prime * result + nextBlockOnDiskSize;
result = prime * result + (int) (offset ^ (offset >>> 32));
result = prime * result + onDiskDataSizeWithHeader;
result = prime * result + onDiskSizeWithoutHeader;
result = prime * result + (int) (prevBlockOffset ^ (prevBlockOffset >>> 32));
result = prime * result + uncompressedSizeWithoutHeader;
return result;
}
@Override
public boolean equals(Object comparison) {
if (this == comparison) {
return true;
}
if (comparison == null) {
return false;
}
if (comparison.getClass() != this.getClass()) {
return false;
}
HFileBlock castedComparison = (HFileBlock) comparison;
if (castedComparison.blockType != this.blockType) {
return false;
}
if (castedComparison.nextBlockOnDiskSize != this.nextBlockOnDiskSize) {
return false;
}
// Offset is important. Needed when we have to remake cachekey when block is returned to cache.
if (castedComparison.offset != this.offset) {
return false;
}
if (castedComparison.onDiskSizeWithoutHeader != this.onDiskSizeWithoutHeader) {
return false;
}
if (castedComparison.prevBlockOffset != this.prevBlockOffset) {
return false;
}
if (castedComparison.uncompressedSizeWithoutHeader != this.uncompressedSizeWithoutHeader) {
return false;
}
if (ByteBufferUtils.compareTo(this.buf, 0, this.buf.limit(), castedComparison.buf, 0,
castedComparison.buf.limit()) != 0) {
return false;
}
return true;
}
public DataBlockEncoding getDataBlockEncoding() {
if (blockType == BlockType.ENCODED_DATA) {
return DataBlockEncoding.getEncodingById(getDataBlockEncodingId());
}
return DataBlockEncoding.NONE;
}
byte getChecksumType() {
return this.fileContext.getChecksumType().getCode();
}
int getBytesPerChecksum() {
return this.fileContext.getBytesPerChecksum();
}
/** @return the size of data on disk + header. Excludes checksum. */
int getOnDiskDataSizeWithHeader() {
return this.onDiskDataSizeWithHeader;
}
/**
* Calculate the number of bytes required to store all the checksums
* for this block. Each checksum value is a 4 byte integer.
*/
int totalChecksumBytes() {
// If the hfile block has minorVersion 0, then there are no checksum
// data to validate. Similarly, a zero value in this.bytesPerChecksum
// indicates that cached blocks do not have checksum data because
// checksums were already validated when the block was read from disk.
if (!fileContext.isUseHBaseChecksum() || this.fileContext.getBytesPerChecksum() == 0) {
return 0;
}
return (int) ChecksumUtil.numBytes(onDiskDataSizeWithHeader,
this.fileContext.getBytesPerChecksum());
}
/**
* Returns the size of this block header.
*/
public int headerSize() {
return headerSize(this.fileContext.isUseHBaseChecksum());
}
/**
* Maps a minor version to the size of the header.
*/
public static int headerSize(boolean usesHBaseChecksum) {
return usesHBaseChecksum?
HConstants.HFILEBLOCK_HEADER_SIZE: HConstants.HFILEBLOCK_HEADER_SIZE_NO_CHECKSUM;
}
/**
* Return the appropriate DUMMY_HEADER for the minor version
*/
byte[] getDummyHeaderForVersion() {
return getDummyHeaderForVersion(this.fileContext.isUseHBaseChecksum());
}
/**
* Return the appropriate DUMMY_HEADER for the minor version
*/
static private byte[] getDummyHeaderForVersion(boolean usesHBaseChecksum) {
return usesHBaseChecksum? HConstants.HFILEBLOCK_DUMMY_HEADER: DUMMY_HEADER_NO_CHECKSUM;
}
/**
* @return This HFileBlocks fileContext which will a derivative of the
* fileContext for the file from which this block's data was originally read.
*/
HFileContext getHFileContext() {
return this.fileContext;
}
/**
* Convert the contents of the block header into a human readable string.
* This is mostly helpful for debugging. This assumes that the block
* has minor version > 0.
*/
@VisibleForTesting
static String toStringHeader(ByteBuffer buf) throws IOException {
byte[] magicBuf = new byte[Math.min(buf.limit() - buf.position(), BlockType.MAGIC_LENGTH)];
buf.get(magicBuf);
BlockType bt = BlockType.parse(magicBuf, 0, BlockType.MAGIC_LENGTH);
int compressedBlockSizeNoHeader = buf.getInt();
int uncompressedBlockSizeNoHeader = buf.getInt();
long prevBlockOffset = buf.getLong();
byte cksumtype = buf.get();
long bytesPerChecksum = buf.getInt();
long onDiskDataSizeWithHeader = buf.getInt();
return " Header dump: magic: " + Bytes.toString(magicBuf) +
" blockType " + bt +
" compressedBlockSizeNoHeader " +
compressedBlockSizeNoHeader +
" uncompressedBlockSizeNoHeader " +
uncompressedBlockSizeNoHeader +
" prevBlockOffset " + prevBlockOffset +
" checksumType " + ChecksumType.codeToType(cksumtype) +
" bytesPerChecksum " + bytesPerChecksum +
" onDiskDataSizeWithHeader " + onDiskDataSizeWithHeader;
}
}