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/**
* ============LICENSE_START=======================================================
* org.onap.aai
* ================================================================================
* Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved.
* ================================================================================
* Licensed 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.
* ============LICENSE_END=========================================================
*/
package org.onap.aai.util;
/*
* logging to hbase encountered hotspotting issues, so per
* http://archive.cloudera.com/cdh5/cdh/5/hbase-0.98.6-cdh5.3.8/book/rowkey.design.html
* we decided to salt the rowkeys
* as these keys are generated in a couple places, I made a class to contain that logic
*/
public class HbaseSaltPrefixer {
private int NUM_REGION_BUCKETS = 3; // the number of hbase region servers per cluster
private static class SingletonHolder {
private static final HbaseSaltPrefixer INSTANCE = new HbaseSaltPrefixer();
}
/**
* Instantiates a new hbase salt prefixer.
*/
private HbaseSaltPrefixer() {
}
/**
* Gets the single instance of HbaseSaltPrefixer.
*
* @return single instance of HbaseSaltPrefixer
*/
public static HbaseSaltPrefixer getInstance() {
return SingletonHolder.INSTANCE;
}
/**
* Prepend salt.
*
* @param key the key
* @return the string
*/
public String prependSalt(String key) {
int salt = Math.abs(key.hashCode()) % NUM_REGION_BUCKETS;
return salt + "-" + key;
}
}
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