timeline
    title 故障時(shí)間軸
    00:00 : 監(jiān)控系統(tǒng)首次告警
    00:05 : 數(shù)據(jù)庫連接池使用率突破90%
    00:08 : 網(wǎng)關(guān)開始出現(xiàn)503錯(cuò)誤
    00:12 : 自動(dòng)擴(kuò)容觸發(fā)
    00:15 : 人工介入排查

// 監(jiān)控工具清單
public class TroubleshootingTools {
    String[] tools = {
        "SkyWalking 8.7.0", 
        "Arthas 3.6.7",
        "Prometheus + Grafana",
        "MySQL Slow Query Log"
    };
}

-- 問題SQL示例
EXPLAIN SELECT * FROM member_info 
WHERE status = 1 
ORDER BY create_time DESC 
LIMIT 10000, 20;

-- 優(yōu)化后SQL（基于ID分頁）
SELECT * FROM member_info 
WHERE status = 1 AND id > #{lastId}
ORDER BY id ASC 
LIMIT 20;

-- 新增復(fù)合索引
ALTER TABLE member_info 
ADD INDEX idx_status_createtime (status, create_time);

-- 改寫SQL
SELECT * FROM member_info 
WHERE status = 1 
ORDER BY create_time DESC 
LIMIT 20;

public interface MemberMapper {
    // 舊方法（問題代碼）
    @Select("SELECT * FROM member_info WHERE status = #{status} LIMIT #{offset}, #{limit}")
    List<Member> listByPage(@Param("status") int status, 
                          @Param("offset") int offset,
                          @Param("limit") int limit);

    // 新方法（優(yōu)化后）
    @Select("SELECT * FROM member_info WHERE status = #{status} AND id > #{lastId} ORDER BY id ASC LIMIT #{limit}")
    List<Member> listByCursor(@Param("status") int status,
                            @Param("lastId") long lastId,
                            @Param("limit") int limit);
}

public PageResult<Member> getMemberList(int pageSize, Long lastId) {
    // 游標(biāo)分頁查詢
    List<Member> members = memberMapper.listByCursor(1, lastId, pageSize);
    
    // 獲取下一頁的游標(biāo)
    Long nextLastId = members.isEmpty() ? null : members.get(members.size()-1).getId();
    
    return new PageResult<>(members, nextLastId);
}

# my.cnf 慢查詢配置
slow_query_log = 1
slow_query_log_file = /var/log/mysql/mysql-slow.log
long_query_time = 1
log_queries_not_using_indexes = 1