com.alibaba.hologres.client.impl.collector.shard.DistributionKeyShardPolicy Maven / Gradle / Ivy

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client for Hologres

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/*
 * Copyright (c) 2021. Alibaba Group Holding Limited
 */

package com.alibaba.hologres.client.impl.collector.shard;

import com.alibaba.hologres.client.impl.util.ShardUtil;
import com.alibaba.hologres.client.model.Record;

import java.util.concurrent.ConcurrentSkipListMap;

/**
 * 使用distribution key去做shard,没有distribution key则随机.
 */
public class DistributionKeyShardPolicy implements ShardPolicy{

	private ConcurrentSkipListMap splitRange = new ConcurrentSkipListMap<>();

	@Override
	public void init(int shardCount) {
		splitRange.clear();
		int[][] range = ShardUtil.split(shardCount);
		for (int i = 0; i < shardCount; ++i) {
			splitRange.put(range[i][0], i);
		}
	}

	@Override
	public int locate(Record record) {
		int raw = ShardUtil.hash(record, record.getSchema().getDistributionKeyIndex());
		int hash = Integer.remainderUnsigned(raw, ShardUtil.RANGE_END);
		return splitRange.floorEntry(hash).getValue();
	}
}