org.apache.hudi.org.apache.hadoop.hbase.regionserver.ScannerIdGenerator Maven / Gradle / Ivy
/**
*
* 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.regionserver;
import org.apache.hbase.thirdparty.com.google.common.hash.Hashing;
import java.util.concurrent.atomic.AtomicInteger;
import org.apache.hadoop.hbase.ServerName;
import org.apache.yetus.audience.InterfaceAudience;
/**
* Generate a new style scanner id to prevent collision with previous started server or other RSs.
* We have 64 bits to use.
* The first 32 bits are MurmurHash32 of ServerName string "host,port,ts".
* The ServerName contains both host, port, and start timestamp so it can prevent collision.
* The lowest 32bit is generated by atomic int.
*/
@InterfaceAudience.Private
public class ScannerIdGenerator {
private final long serverNameHash;
private final AtomicInteger scannerIdGen = new AtomicInteger(0);
public ScannerIdGenerator(ServerName serverName) {
long hash = Hashing.murmur3_32().hashString(serverName.toString(),
java.nio.charset.StandardCharsets.UTF_8).asInt();
this.serverNameHash = hash << 32;
}
public long generateNewScannerId() {
return (scannerIdGen.incrementAndGet() & 0x00000000FFFFFFFFL) | serverNameHash;
}
public static void main(final String [] args) {
ScannerIdGenerator sig = new ScannerIdGenerator(ServerName.valueOf("a.example.org,1234,5678"));
for (int i = 0; i < 10; i++) {
System.out.println(sig.generateNewScannerId());
}
}
}