MySQL中优化CPU使用的详细指南

SELECT * FROM orders WHERE customer_id = 123 AND order_date > '2022-01-01';

EXPLAIN SELECT order_id, order_date, amount FROM orders WHERE customer_id = 123 AND order_date > '2022-01-01';

-- 创建组合索引
CREATE INDEX idx_customer_id_date ON orders (customer_id, order_date);

SELECT * FROM orders WHERE YEAR(order_date) = 2022;

-- 预先创建一个合适的索引
CREATE INDEX idx_order_date ON orders (order_date);

SELECT * FROM orders WHERE order_date BETWEEN '2022-01-01' AND '2022-12-31';

[mysqld]
max_connections = 500  # 根据实际需要设置最大连接数
thread_cache_size = 50  # 缓存线程的数量

[mysqld]
innodb_thread_concurrency = 16  # 限制InnoDB并发线程数
innodb_read_io_threads = 8  # 读取I/O线程数
innodb_write_io_threads = 8  # 写入I/O线程数
innodb_flush_log_at_trx_commit = 2  # 减少日志写入操作
innodb_buffer_pool_instances = 8  # 缓冲池实例数量

[mysqld]
query_cache_type = 1  # 启用查询缓存
query_cache_size = 64M  # 查询缓存的大小
query_cache_limit = 2M  # 单个查询可以使用的最大缓存大小

[mysqld]
tmp_table_size = 256M  # 内存临时表的大小
max_heap_table_size = 256M  # 内存表的最大大小，与tmp_table_size一致
sort_buffer_size = 4M  # 排序操作使用的缓冲区大小
read_buffer_size = 2M  # 顺序扫描使用的缓冲区大小
read_rnd_buffer_size = 4M  # 随机读使用的缓冲区大小

HikariConfig config = new HikariConfig();
config.setJdbcUrl("jdbc:mysql://hostname:3306/database");
config.setUsername("username");
config.setPassword("password");
config.addDataSourceProperty("cachePrepStmts", "true");
config.addDataSourceProperty("prepStmtCacheSize", "250");
config.addDataSourceProperty("prepStmtCacheSqlLimit", "2048");

HikariDataSource ds = new HikariDataSource(config);

try (Connection conn = ds.getConnection()) {
    // 使用连接
}

from sqlalchemy import create_engine

engine = create_engine('mysql+pymysql://username:password@hostname:3306/database', pool_size=10, max_overflow=20)

with engine.connect() as connection:
    result = connection.execute("SELECT * FROM orders")

ALTER TABLE orders ENGINE=InnoDB;

ALTER TABLE orders ENGINE=MyISAM;

OPTIMIZE TABLE orders;

ANALYZE TABLE orders;

# 使用MySQL Tuner
wget http://mysqltuner.pl/ -O mysqltuner.pl
chmod +x mysqltuner.pl
./mysqltuner.pl