Simple spring boot app with Jedis inserting 1M keys in redis using pipelining and multi-threading

RedisMassInport.java

package me.grison.redis.foo;

import org.springframework.boot.CommandLineRunner;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import redis.clients.jedis.Jedis;
import redis.clients.jedis.JedisPool;
import redis.clients.jedis.JedisPoolConfig;
import redis.clients.jedis.Pipeline;

import java.util.UUID;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

@ComponentScan
@Configuration
@SpringBootApplication
@EnableAutoConfiguration
public class RedisMassImport {
	@Bean
	JedisPool jedisPool() {
		JedisPoolConfig poolConfig = new JedisPoolConfig();
		poolConfig.setTestOnBorrow(true);
		poolConfig.setTestWhileIdle(true);
		return new JedisPool(poolConfig, "localhost", 6379, 30);
	}

	@Bean
	CommandLineRunner init(JedisPool pool) {
		return args -> {
			int numKeys = 1_000_000;
			int availableProcessors = Runtime.getRuntime().availableProcessors() * 2;
			ExecutorService exec = Executors.newFixedThreadPool(availableProcessors);

			// pre-compute UUIDs
			String[] uuids = new String[numKeys];
			for (int i = 0; i < numKeys; ++i)
				uuids[i] = UUID.randomUUID().toString();

			// split
			final int portion = numKeys / availableProcessors;
			long time = System.nanoTime();

			for (int i = 0; i < availableProcessors; ++i) {
				final int threadId = i;
				exec.submit(() -> {
					try (Jedis jedis = pool.getResource()) {
						// throw the data at redis
						Pipeline p = jedis.pipelined();
						for (int j = threadId * portion; j < (threadId + 1) * portion; ++j)
							p.set(uuids[j], uuids[j]);
						p.sync();
					}
				});
			}
			exec.shutdown();
			try {
				exec.awaitTermination(Long.MAX_VALUE, TimeUnit.SECONDS);

				long endTime = System.nanoTime();
				System.out.println("\tTook " + (endTime - time) + "ns to sync the pipeline.");
			} catch (InterruptedException e) {
				System.err.println("Execution interrupted: " + e.getMessage());
			}
		};
	}


	public static void main(String[] args) {
		SpringApplication.run(RedisMassImport.class, args);
	}
}