目录
为了在2G内存的学习服务器里运行MySQL、redis和spring boot项目，需要通过配置减少MySQL的内存占用
# 备份配置文件
sudo cp /etc/my.cnf /etc/my.cnf.backup.$(date +%Y%m%d)编辑MySQL配置文件
一般在/etc/my.cnf，增加以下配置
# ========== 内存优化（针对2G服务器） ==========
# MyISAM键缓存（如果不用MyISAM可以更小）
key_buffer_size = 8M
# 连接设置
max_connections = 30 # 限制连接数
thread_cache_size = 4
table_open_cache = 200
# 临时表内存
tmp_table_size = 16M
max_heap_table_size = 16M
# 排序缓冲
sort_buffer_size = 256K
read_buffer_size = 128K
read_rnd_buffer_size = 256K
join_buffer_size = 128K
# ========== 性能优化:InnoDB日志 ==========
innodb_log_buffer_size = 8M
innodb_log_file_size = 32M
innodb_file_per_table = 1
innodb_flush_method = O_DIRECT
innodb_flush_log_at_trx_commit = 2 # 平衡性能和数据安全
# InnoDB缓冲池 - 最重要！设为128M
innodb_buffer_pool_size = 128M
innodb_stats_on_metadata = OFF
# ========== 关闭不必要功能节省内存 ==========
# 关闭性能模式（节省大量内存）
performance_schema = OFF
table_definition_cache = 400
skip_name_resolve = 1
explicit_defaults_for_timestamp = 1
# ========== 慢查询日志设置 ==========
slow_query_log = 1
slow_query_log_file = /var/log/mysql/slow-query.log # 指定慢查询日志文件路径
long_query_time = 2 # 慢查询时间阈值为2秒
# ========== 字符集 ==========
character-set-server = utf8mb4
collation-server = utf8mb4_unicode_ci
[mysql]
default-character-set = utf8mb4
[client]
default-character-set = utf8mb4
socket=/var/lib/mysql/mysql.sock
重启MySQL服务
sudo systemctl restart mysqld 2>/dev/null || sudo systemctl restart mysql检查服务状态
sudo systemctl status mysqld 2>/dev/null || sudo systemctl status mysql
服务状态: active (running)表示成功重启
启动时间: 2025-12-23 16:01:16 CST（已运行2分12秒）
创建慢查询日志目录和文件
# 创建MySQL日志目录
sudo mkdir -p /var/log/mysql
# 创建慢查询日志文件
sudo touch /var/log/mysql/slow-query.log
# 设置正确的所有者和权限
sudo chown -R mysql:mysql /var/log/mysql
sudo chmod 750 /var/log/mysql
sudo chmod 640 /var/log/mysql/*.log
# 查看创建结果
ls -la /var/log/mysql/