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package parallelai.spyglass.hbase;
import java.io.IOException;
import java.util.Arrays;
import java.util.SortedSet;
import java.util.TreeSet;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.io.ImmutableBytesWritable;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Pair;
/**
* Use this Salter if you want maximum efficiency and speed when writing new data into HBase
*
* The 'Region Hot Spot' problem occurs when we are writing in an HBase table data,
* where the key is in sequential order.
*
* http://www.appfirst.com/blog/best-practices-for-managing-hbase-in-a-high-write-environment/
*
* By using this salter we can prefix the keys with a character followed by an _
* i.e.
*
* SCALDING -> G_SCALDING
*
* and thus distribute better the write load in the HBase cluster
*/
public class HBaseSalter {
private static final Log LOG = LogFactory.getLog(HBaseSalter.class);
public static byte [] addSaltPrefix(byte [] key) throws IOException {
if( key == null || key.length < 1 ) throw new IOException("Input Key is EMPTY or Less than 1 Character Long");
String keyStr = Bytes.toString(key);
return Bytes.toBytes(keyStr.substring(keyStr.length() - 1) + "_" + keyStr);
}
public static String addSaltPrefix(String key) throws IOException {
if( key == null || key.length() < 1 ) throw new IOException("Input Key is EMPTY or Less than 1 Character Long");
return (key.substring(key.length() - 1) + "_" + key);
}
public static ImmutableBytesWritable addSaltPrefix( ImmutableBytesWritable key ) throws IOException {
return new ImmutableBytesWritable( addSaltPrefix(key.get()));
}
public static byte [] delSaltPrefix(byte [] key) throws IOException {
if( key == null || key.length < 3 ) throw new IOException("Input Key is EMPTY or Less than 3 Characters Long");
String keyStr = Bytes.toString(key);
return Bytes.toBytes(keyStr.substring(2));
}
public static String delSaltPrefix(String key) throws IOException {
if( key == null || key.length() < 3 ) throw new IOException("Input Key is EMPTY or Less than 3 Characters Long");
return key.substring(2);
}
public static ImmutableBytesWritable delSaltPrefix( ImmutableBytesWritable key ) throws IOException {
return new ImmutableBytesWritable( delSaltPrefix(key.get()));
}
public static final String DEFAULT_PREFIX_LIST = " !\"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~";
public static Pair<byte[], byte[]>[] getDistributedIntervals(byte[] originalStartKey, byte[] originalStopKey) throws IOException {
return getDistributedIntervals(originalStartKey, originalStopKey, DEFAULT_PREFIX_LIST);
}
public static Pair<byte[], byte[]>[] getDistributedIntervals(byte[] originalStartKey, byte[] originalStopKey, String prefixList) throws IOException {
return getDistributedIntervals(originalStartKey, originalStopKey, HConstants.EMPTY_START_ROW, HConstants.EMPTY_END_ROW, prefixList);
}
public static Pair<byte[], byte[]>[] getDistributedIntervals(
byte[] originalStartKey, byte[] originalStopKey,
byte[] regionStartKey, byte[] regionStopKey,
String prefixList) throws IOException {
LOG.debug("".format("OSRT: (%s) OSTP: (%s) RSRT: (%s) RSTP: (%s) PRFX: (%s)",
Bytes.toString(originalStartKey),
Bytes.toString(originalStopKey),
Bytes.toString(regionStartKey),
Bytes.toString(regionStopKey),
prefixList
));
byte[][] startKeys;
byte[][] stopKeys;
if(Arrays.equals(regionStartKey, HConstants.EMPTY_START_ROW)
&& Arrays.equals(regionStopKey, HConstants.EMPTY_END_ROW) ) {
startKeys = getAllKeys(originalStartKey, prefixList);
stopKeys = getAllKeys(originalStopKey, prefixList);
} else if(Arrays.equals(regionStartKey, HConstants.EMPTY_START_ROW)) {
startKeys = getAllKeysWithStop(originalStartKey, prefixList, regionStopKey[0]);
stopKeys = getAllKeysWithStop(originalStopKey, prefixList, regionStopKey[0]);
} else if(Arrays.equals(regionStopKey, HConstants.EMPTY_END_ROW)) {
startKeys = getAllKeysWithStart(originalStartKey, prefixList, regionStartKey[0]);
stopKeys = getAllKeysWithStart(originalStopKey, prefixList, regionStartKey[0]);
} else {
startKeys = getAllKeysInRange(originalStartKey, prefixList, regionStartKey[0], regionStopKey[0]);
stopKeys = getAllKeysInRange(originalStopKey, prefixList, regionStartKey[0], regionStopKey[0]);
}
if( startKeys.length != stopKeys.length) {
throw new IOException("LENGTH of START Keys and STOP Keys DO NOT match");
}
if( Arrays.equals(originalStartKey, HConstants.EMPTY_START_ROW)
&& Arrays.equals(originalStopKey, HConstants.EMPTY_END_ROW) ) {
Arrays.sort(stopKeys, Bytes.BYTES_RAWCOMPARATOR);
// stop keys are the start key of the next interval
for (int i = startKeys.length - 1; i >= 1; i--) {
startKeys[i] = startKeys[i - 1];
}
startKeys[0] = HConstants.EMPTY_START_ROW;
stopKeys[stopKeys.length - 1] = HConstants.EMPTY_END_ROW;
} else if (Arrays.equals(originalStartKey, HConstants.EMPTY_START_ROW)) {
Arrays.sort(stopKeys, Bytes.BYTES_RAWCOMPARATOR);
// stop keys are the start key of the next interval
for (int i = startKeys.length - 1; i >= 1; i--) {
startKeys[i] = startKeys[i - 1];
}
startKeys[0] = HConstants.EMPTY_START_ROW;
} else if (Arrays.equals(originalStopKey, HConstants.EMPTY_END_ROW)) {
Arrays.sort(startKeys, Bytes.BYTES_RAWCOMPARATOR);
// stop keys are the start key of the next interval
for (int i = 0; i < stopKeys.length - 1; i++) {
stopKeys[i] = stopKeys[i + 1];
}
stopKeys[stopKeys.length - 1] = HConstants.EMPTY_END_ROW;
}
Pair<byte[], byte[]>[] intervals = new Pair[startKeys.length];
for (int i = 0; i < startKeys.length; i++) {
intervals[i] = new Pair<byte[], byte[]>(startKeys[i], stopKeys[i]);
}
return intervals;
}
public static byte[][] getAllKeys(byte[] originalKey) throws IOException {
return getAllKeys(originalKey, DEFAULT_PREFIX_LIST);
}
public static byte[][] getAllKeys(byte[] originalKey, String prefixList) throws IOException {
char[] prefixArray = prefixList.toCharArray();
return getAllKeysWithStartStop(originalKey, prefixList, (byte)prefixArray[0], (byte)prefixArray[prefixArray.length - 1]);
}
public static byte[][] getAllKeysWithStart(byte[] originalKey, String prefixList, byte startKey) throws IOException {
char[] prefixArray = prefixList.toCharArray();
return getAllKeysWithStartStop(originalKey, prefixList, startKey, (byte)prefixArray[prefixArray.length - 1]);
}
public static byte[][] getAllKeysWithStop(byte[] originalKey, String prefixList, byte stopKey) throws IOException {
char[] prefixArray = prefixList.toCharArray();
return getAllKeysWithStartStop(originalKey, prefixList, (byte)prefixArray[0], stopKey);
}
public static byte[][] getAllKeysInRange(byte[] originalKey, String prefixList, byte startPrefix, byte stopPrefix) {
return getAllKeysWithStartStop(originalKey, prefixList, startPrefix, stopPrefix);
}
private static byte[][] getAllKeysWithStartStop(byte[] originalKey, String prefixList, byte startPrefix, byte stopPrefix) {
LOG.debug("".format("getAllKeysWithStartStop: OKEY (%s) PLIST (%s) PSRT (%s) PSTP (%s)",
Bytes.toString(originalKey), prefixList, startPrefix, stopPrefix));
char[] prefixArray = prefixList.toCharArray();
TreeSet<Byte> prefixSet = new TreeSet<Byte>();
for( char c : prefixArray ) {
prefixSet.add((byte)c);
}
SortedSet<Byte> subSet = prefixSet.subSet(startPrefix, true, stopPrefix, true);
LOG.debug("".format("Prefix subset (%s)", subSet));
return getAllKeys(originalKey, subSet.toArray(new Byte[]{}));
}
public static byte[][] getAllKeys(byte[] originalKey, Byte [] prefixArray) {
LOG.debug("".format("getAllKeys: OKEY (%s) PARRAY (%s)",
Bytes.toString(originalKey), prefixArray ));
byte[][] keys = new byte[prefixArray.length][];
for (byte i = 0; i < prefixArray.length; i++) {
keys[i] = Bytes.add(new byte[] {prefixArray[i].byteValue()}, Bytes.add( Bytes.toBytes("_"), originalKey));
}
return keys;
}
public static void main(String [] args) throws IOException {
String s = "";
for (byte i = 32; i < Byte.MAX_VALUE; i++) {
s += (char)i;
}
System.out.println("".format("[%s]", s));
System.out.println("".format("[%s]", DEFAULT_PREFIX_LIST));
String start = Bytes.toString(HConstants.EMPTY_START_ROW);
String stop = Bytes.toString(HConstants.EMPTY_END_ROW);
System.out.println("".format("START: (%s) STOP: (%s)", start, stop));
Pair<byte[], byte[]>[] intervals = getDistributedIntervals(Bytes.toBytes(start), Bytes.toBytes(stop), "1423");
for( Pair<byte[], byte[]> p : intervals ) {
System.out.println("".format("iSTART: (%s) iSTOP: (%s)", Bytes.toString(p.getFirst()), Bytes.toString(p.getSecond())));
}
}
}
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