/etc/mysql/mysql.conf.d/mysqld.cnf 中加入以下关键配置
[mysqld]
# 1. 核心：限制缓冲池 (生死线)
innodb_buffer_pool_size = 64M
# 如果 64M 还不够稳，可以降到 32M，只是查询稍慢
# 2. 关键：关闭性能监控 (MySQL 8 的内存杀手！)
# 这个选项默认开启，能吃掉 100MB+ 内存，必须关掉
performance_schema = OFF
# 3. 禁用自适应哈希索引 (省内存，换轻微 CPU)
innodb_adaptive_hash_index = OFF
# 4. 限制连接数 (防止并发撑爆)
max_connections = 20
# 5. 压缩每连接缓冲区 (KB 级别)
sort_buffer_size = 64K
read_buffer_size = 64K
read_rnd_buffer_size = 64K
join_buffer_size = 64K
# 6. 临时表限制 (超过即落盘)
max_heap_table_size = 4M
tmp_table_size = 4M
# 7. 减少后台 IO 线程
innodb_read_io_threads = 2
innodb_write_io_threads = 2