数据Rebalance (RebalanceBatchOp)

Java 类名：com.alibaba.alink.operator.batch.dataproc.RebalanceBatchOp
Python 类名：RebalanceBatchOp

功能介绍

该组件对数据进行 rebalance。

实现原理

将数据按轮转（round-robin）的方式划分分区，后续每个 worker 处理一个分区，各个分区间负载相等。
可以用于优化数据倾斜带来的性能问题。

参数说明

代码示例

Python 代码

from pyalink.alink import *
import pandas as pd
useLocalEnv(1)
df = pd.DataFrame([
       ["0,0,0"],
       ["0.1,0.1,0.1"],
       ["0.2,0.2,0.2"],
       ["9,9,9"],
       ["9.1,9.1,9.1"],
       ["9.2,9.2,9.2"]
])
inOp = BatchOperator.fromDataframe(df, schemaStr='Y string')
inOp.link(RebalanceBatchOp()).print()

Java 代码

import org.apache.flink.types.Row;
import com.alibaba.alink.operator.batch.BatchOperator;
import com.alibaba.alink.operator.batch.dataproc.RebalanceBatchOp;
import com.alibaba.alink.operator.batch.source.MemSourceBatchOp;
import org.junit.Test;
import java.util.Arrays;
import java.util.List;
public class RebalanceBatchOpTest {
    @Test
    public void testRebalanceBatchOp() throws Exception {
        List <Row> df = Arrays.asList(
            Row.of("0,0,0"),
            Row.of("0.1,0.1,0.1"),
            Row.of("0.2,0.2,0.2"),
            Row.of("9,9,9"),
            Row.of("9.1,9.1,9.1"),
            Row.of("9.2,9.2,9.2")
        );
        BatchOperator <?> inOp = new MemSourceBatchOp(df, "Y string");
        inOp.link(new RebalanceBatchOp()).print();
    }
}

运行结果

| Y | | —- |

| 0,0,0 |

| 0.1,0.1,0.1 |

| 0.2,0.2,0.2 |

| 9,9,9 |

| 9.1,9.1,9.1 |

| 9.2,9.2,9.2 |