Test creating 100k tables in greptimedb

CreateTablesTest.java

package com.greptime;

import static org.junit.Assert.assertTrue;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import java.util.concurrent.CyclicBarrier;
import java.util.concurrent.ThreadLocalRandom;
import java.util.concurrent.atomic.AtomicInteger;

import org.junit.Test;

/**
 * Unit test for simple App.
 */
public class CreateTablesTest {
	@Test
	public void testGreptimeDB() throws Exception {
		int tables = 100000;
		int tags = 100;
		int tagsPerTable = 15;
		// Execute "CREATE TABLE phy (ts timestamp time index, val double) engine=metric
		// with ("physical_metric_table" = "");"
		boolean isMetricsTable = true;

		String[] demoTags = new String[tags];
		for (int i = 0; i < tags; i++) {
			demoTags[i] = "tag_" + i;
		}

		Class.forName("com.mysql.cj.jdbc.Driver");
		final ThreadLocalRandom rand = ThreadLocalRandom.current();

		if (isMetricsTable) {
			Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:4002/public", "root", "password");
			Statement stmt = conn.createStatement();
			stmt.execute(
					"CREATE TABLE IF NOT EXISTS phy (ts timestamp time index, val double) engine=metric with (\"physical_metric_table\" = \"\")");
			stmt.close();
			conn.close();
		}

		int threads = 10;
		int partitons = tables / threads;

		CyclicBarrier barrier = new CyclicBarrier(threads + 1);
		AtomicInteger counter = new AtomicInteger(0);

		for (int t = 0; t < threads; t++) {
			final int threadsNumber = t;
			Thread thread = new Thread() {
				public void run() {
					try {
						Connection conn = DriverManager.getConnection("jdbc:mysql://localhost:4002/public", "root",
								"password");
						Statement stmt = conn.createStatement();
						barrier.await();
						for (int i = threadsNumber * partitons; i < threadsNumber * partitons + partitons; i++) {

							StringBuilder sql = new StringBuilder("create table test_") //
									.append(i) //
									.append("("); //

							StringBuilder priKeys = new StringBuilder();

							Set<String> tagSet = new HashSet<String>();

							for (int j = 0; j < tagsPerTable; j++) {
								String tag = null;

								while (tag == null || tagSet.contains(tag)) {
									tag = demoTags[rand.nextInt(tags)];
								}
								tagSet.add(tag);

								sql.append(tag).append(" string").append(",");
								priKeys.append(tag);
								if (j != tagsPerTable - 1) {
									priKeys.append(",");
								}
							}
							sql.append("ts timestamp time index, val double, primary key(") //
									.append(priKeys)//
									.append("))");//

							if (isMetricsTable) {
								sql.append(" engine = metric with (\"on_physical_table\" = \"phy\")");
							} else {
								sql.append(" engine = mito");
							}

							stmt.execute(sql.toString());

							int c = counter.incrementAndGet();
							if (c % 1000 == 0) {
								System.out.println("Created " + c + " tables...");
							}

						}
						stmt.close();
						conn.close();
						barrier.await();
					} catch (Exception e) {
						e.printStackTrace();
						System.exit(1);
					}
				}
			};

			thread.start();

			System.out.println("Threads " + t + " started");
		}

		long start = System.currentTimeMillis();
		barrier.await();
		barrier.await();

		System.out.println("Created " + tables + "tables with " + tags + " tags, cost:"
				+ ((System.currentTimeMillis() - start) / 1000.0) + " seconds.");

	}
}