Analysis of practical methods of Java technology to improve database search efficiency
Data plays an extremely important role in the modern Internet era, whether it is an e-commerce website or a financial system. A large amount of data needs to be searched and queried. In scenarios where massive amounts of data are processed, how to improve database search efficiency has become an urgent issue. This article will share with you some practical methods that can be used to improve database search efficiency in Java technology, and provide specific code examples.
Code example:
CREATE INDEX idx_user_id ON user (user_id); -- 创建主键索引 CREATE UNIQUE INDEX idx_product_sku ON product (sku); -- 创建唯一索引 CREATE INDEX idx_product_category ON product (category_id, brand_id); -- 创建联合索引
OFFSET
and LIMIT
keywords, because this will cause the database to scan a large amount of useless data during the query. The efficiency of paging queries can be improved by using methods such as "paging mark" or "paging query optimization plug-in". Code example:
SELECT * FROM user WHERE user_id > ? ORDER BY user_id LIMIT 10; -- 分页标记法
Code example:
public User getUserById(Long userId) { User user = redisClient.get("user_" + userId); // 先从缓存中获取数据 if (user == null) { user = userDao.getUserById(userId); // 如果缓存中没有,则从数据库查询 redisClient.set("user_" + userId, user, 300); // 将数据放入缓存,并设置过期时间为300秒 } return user; }
SELECT *
. Selecting only the required fields can reduce the amount of query data. At the same time, try to avoid using IN
and NOT. Operators such as IN
and LIKE
, because these operators will cause a full table scan and poor performance. In addition, the JOIN
and WHERE
clauses can be used appropriately to reduce data association and filtering and improve query efficiency. Code example:
SELECT user_id, username FROM user WHERE age > 18; -- 只选择需要的字段 SELECT user_id, username FROM user WHERE username LIKE 'abc%'; -- 尽量避免使用LIKE操作符 SELECT u.user_id, u.username, o.order_id FROM user u JOIN orders o ON u.user_id = o.user_id; -- 合理使用JOIN子句
Code example:
HikariDataSource dataSource = new HikariDataSource(); dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/mydb"); dataSource.setUsername("username"); dataSource.setPassword("password"); dataSource.setMaximumPoolSize(100); dataSource.setMinimumIdle(10);
Through the above practical methods, we can effectively improve the efficiency of database search, so that the system can handle massive data query requests more efficiently. Of course, this is not the only solution. Depending on actual needs and specific circumstances, we can also combine other technical means to optimize database search efficiency. I hope this article can help everyone understand and apply methods to improve database search efficiency in Java technology.
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