MySQL数据库崩溃问题的检测与解决方法

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;

public class DatabaseHealthChecker {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/my_database";
        String user = "root";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password)) {
            System.out.println("Database is running.");
        } catch (SQLException e) {
            System.err.println("Failed to connect to the database.");
            e.printStackTrace();
        }
    }
}

sudo systemctl restart mysql

sudo service mysql restart

import java.io.BufferedReader;
import java.io.InputStreamReader;

public class DatabaseRestoreFromBackup {
    public static void main(String[] args) {
        String restoreCommand = "mysql -u root -p password my_database < /path/to/backup/my_database.sql";

        try {
            Process process = Runtime.getRuntime().exec(restoreCommand);
            int processComplete = process.waitFor();

            if (processComplete == 0) {
                System.out.println("Database restored successfully.");
            } else {
                System.err.println("Failed to restore the database.");
                try (BufferedReader br = new BufferedReader(new InputStreamReader(process.getErrorStream()))) {
                    br.lines().forEach(System.err::println);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.sql.Statement;

public class CheckAndRepairTables {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/my_database";
        String user = "root";
        String password = "password";

        try (Connection conn = DriverManager.getConnection(url, user, password);
             Statement stmt = conn.createStatement()) {

            // 检查和修复表
            String checkTableSQL = "CHECK TABLE my_table";
            String repairTableSQL = "REPAIR TABLE my_table";

            stmt.execute(checkTableSQL);
            stmt.execute(repairTableSQL);

            System.out.println("Tables checked and repaired if necessary.");

        } catch (SQLException e) {
            e.printStackTrace();
        }
    }
}

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;

public class MySQLErrorLogParser {
    public static void main(String[] args) {
        String logFilePath = "/var/log/mysql/error.log";

        try (BufferedReader br = new BufferedReader(new FileReader(logFilePath))) {
            String line;
            while ((line = br.readLine()) != null) {
                System.out.println(line);
                // 可以根据具体需求分析和过滤日志信息
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

import java.util.Properties;
import javax.mail.*;
import javax.mail.internet.*;

public class AlertSender {
    public static void main(String[] args) {
        String to = "admin@example.com";
        String from = "monitor@example.com";
        String host = "smtp.example.com";
        String username = "smtp_user";
        String password = "smtp_password";

        Properties properties = System.getProperties();
        properties.setProperty("mail.smtp.host", host);
        properties.setProperty("mail.smtp.port", "587");
        properties.setProperty("mail.smtp.auth", "true");
        properties.setProperty("mail.smtp.starttls.enable", "true");

        Session session = Session.getInstance(properties, new Authenticator() {
            protected PasswordAuthentication getPasswordAuthentication() {
                return new PasswordAuthentication(username, password);
            }
        });

        try {
            MimeMessage message = new MimeMessage(session);
            message.setFrom(new InternetAddress(from));
            message.addRecipient(Message.RecipientType.TO, new InternetAddress(to));
            message.setSubject("Database Alert");
            message.setText("Database has crashed. Immediate attention is required.");

            Transport.send(message);
            System.out.println("Alert email sent successfully.");
        } catch (MessagingException mex) {
            mex.printStackTrace();
        }
    }
}

#!/bin/bash

# 检查MySQL服务状态
if systemctl is-active --quiet mysql
then
    echo "MySQL is running."
else
    echo "MySQL is not running. Attempting to restart."
    systemctl restart mysql
    if systemctl is-active --quiet mysql
    then
        echo "MySQL restarted successfully."
    else
        echo "MySQL failed to restart."
        # 发送报警邮件
        echo "MySQL service failed to restart." | mail -s "Database Alert" admin@example.com
    fi
fi

# 检查和修复数据表
mysqlcheck -u root -p'password' --auto-repair --all-databases