/*
* 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.codec.prefixtree;
import java.nio.ByteBuffer;
import org.apache.hadoop.hbase.Cell;
import org.apache.hadoop.hbase.CellUtil;
import org.apache.hadoop.hbase.KeyValue;
import org.apache.hadoop.hbase.KeyValue.KVComparator;
import org.apache.hadoop.hbase.KeyValue.Type;
import org.apache.hadoop.hbase.KeyValueUtil;
import org.apache.hadoop.hbase.SettableSequenceId;
import org.apache.hadoop.hbase.classification.InterfaceAudience;
import org.apache.hadoop.hbase.codec.prefixtree.decode.DecoderFactory;
import org.apache.hadoop.hbase.codec.prefixtree.decode.PrefixTreeArraySearcher;
import org.apache.hadoop.hbase.codec.prefixtree.scanner.CellScannerPosition;
import org.apache.hadoop.hbase.io.HeapSize;
import org.apache.hadoop.hbase.io.encoding.DataBlockEncoder.EncodedSeeker;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.ClassSize;
/**
* These methods have the same definition as any implementation of the EncodedSeeker.
*
* In the future, the EncodedSeeker could be modified to work with the Cell interface directly. It
* currently returns a new KeyValue object each time getKeyValue is called. This is not horrible,
* but in order to create a new KeyValue object, we must first allocate a new byte[] and copy in
* the data from the PrefixTreeCell. It is somewhat heavyweight right now.
*/
@InterfaceAudience.Private
public class PrefixTreeSeeker implements EncodedSeeker {
protected ByteBuffer block;
protected boolean includeMvccVersion;
protected PrefixTreeArraySearcher ptSearcher;
public PrefixTreeSeeker(boolean includeMvccVersion) {
this.includeMvccVersion = includeMvccVersion;
}
@Override
public void setCurrentBuffer(ByteBuffer fullBlockBuffer) {
block = fullBlockBuffer;
ptSearcher = DecoderFactory.checkOut(block, includeMvccVersion);
rewind();
}
/**
* Currently unused.
* <p/>
* TODO performance leak. should reuse the searchers. hbase does not currently have a hook where
* this can be called
*/
public void releaseCurrentSearcher(){
DecoderFactory.checkIn(ptSearcher);
}
@Override
public ByteBuffer getKeyDeepCopy() {
return KeyValueUtil.copyKeyToNewByteBuffer(ptSearcher.current());
}
@Override
public ByteBuffer getValueShallowCopy() {
return CellUtil.getValueBufferShallowCopy(ptSearcher.current());
}
/**
* currently must do deep copy into new array
*/
@Override
public ByteBuffer getKeyValueBuffer() {
return KeyValueUtil.copyToNewByteBuffer(ptSearcher.current());
}
/**
* currently must do deep copy into new array
*/
@Override
public Cell getKeyValue() {
Cell cell = ptSearcher.current();
if (cell == null) {
return null;
}
return new ClonedPrefixTreeCell(cell.getRowArray(), cell.getRowOffset(), cell.getRowLength(),
cell.getFamilyArray(), cell.getFamilyOffset(), cell.getFamilyLength(),
cell.getQualifierArray(), cell.getQualifierOffset(), cell.getQualifierLength(),
cell.getValueArray(), cell.getValueOffset(), cell.getValueLength(), cell.getTagsArray(),
cell.getTagsOffset(), cell.getTagsLength(), cell.getTimestamp(), cell.getTypeByte(),
cell.getSequenceId());
}
/**
* Currently unused.
* <p/>
* A nice, lightweight reference, though the underlying cell is transient. This method may return
* the same reference to the backing PrefixTreeCell repeatedly, while other implementations may
* return a different reference for each Cell.
* <p/>
* The goal will be to transition the upper layers of HBase, like Filters and KeyValueHeap, to
* use this method instead of the getKeyValue() methods above.
*/
public Cell get() {
return ptSearcher.current();
}
@Override
public void rewind() {
ptSearcher.positionAtFirstCell();
}
@Override
public boolean next() {
boolean advance = ptSearcher.advance();
if (ptSearcher.hasMovedToPreviousAsPartOfSeek()) {
ptSearcher.setMovedToPreviousAsPartOfSeek(false);
}
return advance;
}
// @Override
public boolean advance() {
return ptSearcher.advance();
}
private static final boolean USE_POSITION_BEFORE = false;
/**
* Seek forward only (should be called reseekToKeyInBlock?).
* <p/>
* If the exact key is found look at the seekBefore variable and:<br/>
* - if true: go to the previous key if it's true<br/>
* - if false: stay on the exact key
* <p/>
* If the exact key is not found, then go to the previous key *if possible*, but remember to
* leave the scanner in a valid state if possible.
* <p/>
* @param keyOnlyBytes KeyValue format of a Cell's key at which to position the seeker
* @param offset offset into the keyOnlyBytes array
* @param length number of bytes of the keyOnlyBytes array to use
* @param forceBeforeOnExactMatch if an exact match is found and seekBefore=true, back up 1 Cell
* @return 0 if the seeker is on the exact key<br/>
* 1 if the seeker is not on the key for any reason, including seekBefore being true
*/
@Override
public int seekToKeyInBlock(byte[] keyOnlyBytes, int offset, int length,
boolean forceBeforeOnExactMatch) {
if (USE_POSITION_BEFORE) {
return seekToOrBeforeUsingPositionAtOrBefore(keyOnlyBytes, offset, length,
forceBeforeOnExactMatch);
} else {
return seekToOrBeforeUsingPositionAtOrAfter(keyOnlyBytes, offset, length,
forceBeforeOnExactMatch);
}
}
/*
* Support both of these options since the underlying PrefixTree supports both. Possibly
* expand the EncodedSeeker to utilize them both.
*/
protected int seekToOrBeforeUsingPositionAtOrBefore(byte[] keyOnlyBytes, int offset, int length,
boolean seekBefore){
// this does a deep copy of the key byte[] because the CellSearcher interface wants a Cell
KeyValue kv = new KeyValue.KeyOnlyKeyValue(keyOnlyBytes, offset, length);
return seekToOrBeforeUsingPositionAtOrBefore(kv, seekBefore);
}
/*
* Support both of these options since the underlying PrefixTree supports
* both. Possibly expand the EncodedSeeker to utilize them both.
*/
protected int seekToOrBeforeUsingPositionAtOrBefore(Cell kv, boolean seekBefore) {
// this does a deep copy of the key byte[] because the CellSearcher
// interface wants a Cell
CellScannerPosition position = ptSearcher.seekForwardToOrBefore(kv);
if (CellScannerPosition.AT == position) {
if (seekBefore) {
ptSearcher.previous();
return 1;
}
return 0;
}
return 1;
}
protected int seekToOrBeforeUsingPositionAtOrAfter(byte[] keyOnlyBytes, int offset, int length,
boolean seekBefore) {
// this does a deep copy of the key byte[] because the CellSearcher
// interface wants a Cell
KeyValue kv = new KeyValue.KeyOnlyKeyValue(keyOnlyBytes, offset, length);
return seekToOrBeforeUsingPositionAtOrAfter(kv, seekBefore);
}
protected int seekToOrBeforeUsingPositionAtOrAfter(Cell kv, boolean seekBefore) {
// should probably switch this to use the seekForwardToOrBefore method
CellScannerPosition position = ptSearcher.seekForwardToOrAfter(kv);
if (CellScannerPosition.AT == position) {
if (seekBefore) {
// We need not set movedToPrevious because the intention is to seekBefore
ptSearcher.previous();
return 1;
}
return 0;
}
if (CellScannerPosition.AFTER == position) {
if (!ptSearcher.isBeforeFirst()) {
ptSearcher.previous();
ptSearcher.setMovedToPreviousAsPartOfSeek(true);
}
return 1;
}
if (position == CellScannerPosition.AFTER_LAST) {
if (seekBefore) {
ptSearcher.previous();
}
return 1;
}
throw new RuntimeException("unexpected CellScannerPosition:" + position);
}
@Override
public int compareKey(KVComparator comparator, byte[] key, int offset, int length) {
// can't optimize this, make a copy of the key
ByteBuffer bb = getKeyDeepCopy();
return comparator.compareFlatKey(key, offset, length, bb.array(), bb.arrayOffset(), bb.limit());
}
@Override
public int seekToKeyInBlock(Cell key, boolean forceBeforeOnExactMatch) {
if (USE_POSITION_BEFORE) {
return seekToOrBeforeUsingPositionAtOrBefore(key, forceBeforeOnExactMatch);
} else {
return seekToOrBeforeUsingPositionAtOrAfter(key, forceBeforeOnExactMatch);
}
}
@Override
public int compareKey(KVComparator comparator, Cell key) {
ByteBuffer bb = getKeyDeepCopy();
return comparator.compare(key,
new KeyValue.KeyOnlyKeyValue(bb.array(), bb.arrayOffset(), bb.limit()));
}
/**
* Cloned version of the PrefixTreeCell where except the value part, the rest
* of the key part is deep copied
*
*/
private static class ClonedPrefixTreeCell implements Cell, SettableSequenceId, HeapSize {
private static final long FIXED_OVERHEAD = ClassSize.align(ClassSize.OBJECT
+ (5 * ClassSize.REFERENCE) + (2 * Bytes.SIZEOF_LONG) + (4 * Bytes.SIZEOF_INT)
+ (Bytes.SIZEOF_SHORT) + (2 * Bytes.SIZEOF_BYTE) + (5 * ClassSize.ARRAY));
private byte[] row;
private short rowLength;
private byte[] fam;
private byte famLength;
private byte[] qual;
private int qualLength;
private byte[] val;
private int valOffset;
private int valLength;
private byte[] tag;
private int tagsLength;
private long ts;
private long seqId;
private byte type;
public ClonedPrefixTreeCell(byte[] row, int rowOffset, short rowLength, byte[] fam,
int famOffset, byte famLength, byte[] qual, int qualOffset, int qualLength, byte[] val,
int valOffset, int valLength, byte[] tag, int tagOffset, int tagLength, long ts, byte type,
long seqId) {
this.row = new byte[rowLength];
System.arraycopy(row, rowOffset, this.row, 0, rowLength);
this.rowLength = rowLength;
this.fam = new byte[famLength];
System.arraycopy(fam, famOffset, this.fam, 0, famLength);
this.famLength = famLength;
this.qual = new byte[qualLength];
System.arraycopy(qual, qualOffset, this.qual, 0, qualLength);
this.qualLength = qualLength;
this.tag = new byte[tagLength];
System.arraycopy(tag, tagOffset, this.tag, 0, tagLength);
this.tagsLength = tagLength;
this.val = val;
this.valLength = valLength;
this.valOffset = valOffset;
this.ts = ts;
this.seqId = seqId;
this.type = type;
}
@Override
public void setSequenceId(long seqId) {
this.seqId = seqId;
}
@Override
public byte[] getRowArray() {
return this.row;
}
@Override
public int getRowOffset() {
return 0;
}
@Override
public short getRowLength() {
return this.rowLength;
}
@Override
public byte[] getFamilyArray() {
return this.fam;
}
@Override
public int getFamilyOffset() {
return 0;
}
@Override
public byte getFamilyLength() {
return this.famLength;
}
@Override
public byte[] getQualifierArray() {
return this.qual;
}
@Override
public int getQualifierOffset() {
return 0;
}
@Override
public int getQualifierLength() {
return this.qualLength;
}
@Override
public long getTimestamp() {
return ts;
}
@Override
public byte getTypeByte() {
return type;
}
@Override
@Deprecated
public long getMvccVersion() {
return getSequenceId();
}
@Override
public long getSequenceId() {
return seqId;
}
@Override
public byte[] getValueArray() {
return val;
}
@Override
public int getValueOffset() {
return this.valOffset;
}
@Override
public int getValueLength() {
return this.valLength;
}
@Override
public byte[] getTagsArray() {
return this.tag;
}
@Override
public int getTagsOffset() {
return 0;
}
@Override
public int getTagsLength() {
return this.tagsLength;
}
@Override
@Deprecated
public byte[] getValue() {
return this.val;
}
@Override
@Deprecated
public byte[] getFamily() {
return this.fam;
}
@Override
@Deprecated
public byte[] getQualifier() {
return this.qual;
}
@Override
@Deprecated
public byte[] getRow() {
return this.row;
}
@Override
public String toString() {
String row = Bytes.toStringBinary(getRowArray(), getRowOffset(), getRowLength());
String family = Bytes.toStringBinary(getFamilyArray(), getFamilyOffset(), getFamilyLength());
String qualifier = Bytes.toStringBinary(getQualifierArray(), getQualifierOffset(),
getQualifierLength());
String timestamp = String.valueOf((getTimestamp()));
return row + "/" + family + (family != null && family.length() > 0 ? ":" : "") + qualifier
+ "/" + timestamp + "/" + Type.codeToType(type);
}
@Override
public long heapSize() {
return FIXED_OVERHEAD + rowLength + famLength + qualLength + valLength + tagsLength;
}
}
}