Home Backend Development PHP Tutorial mysql表列复制,mysql连接时间跟内存控制

mysql表列复制,mysql连接时间跟内存控制

Jun 13, 2016 pm 12:46 PM
escape mysql nbsp query string

mysql表列复制,mysql连接时间和内存控制。
有两个表临时表temp_t,和正表table1,都是MyISAM,分别有28W条左右的记录。
cron定时每分钟从网络上获取一些信息,先存储到temp_t(频繁写入),
然后cron定时每10分钟从temp_t复制信息到正表table1(频繁读取,每10分钟写一次)。

temp_t字段 id(auto_increment),title(varchar(200)),content(varchar(500)),date(DATETIME), mykey(tinyint(1) Default 1, 这个来判别是否已经复制到正表,复制过后UPDATE为2)

table1字段 id(没有auto_increment),title(varchar(200)),content(varchar(500)),date(DATETIME)


28W记录,每个数据表大概有300MB,每次更新差不多要2K-3K条记录。
如果直接复制的话,MYSQL连接时间过长,导致MYSQL性能下降table1会出现类似于锁表的现象,查询table1的时间明显加长

require dirname(__FILE__) . '/../connection.php';<br />
mysql_select_db("news",$connextion);<br />
mysql_query("SET NAMES utf8");<br />
$query = mysql_query("SELECT * FROM temp_t where mykey = '1'");<br />
while($rows = mysql_fetch_array($query)){<br />
	mysql_query("UPDATE temp_t SET mykey='2' WHERE id='".mysql_real_escape_string($rows['id'])."'");<br />
	mysql_query("INSERT INTO table1 (id,title,content,date) values ('".mysql_real_escape_string($rows['id'])."','".mysql_real_escape_string($rows['title'])."','".mysql_real_escape_string($rows['content'])."','".mysql_real_escape_string($rows['date'])."'");<br />
}<br />
mysql_close($connextion);
Copy after login



于是想先把记录从temp_t里的数据先读出来,存为一个json数组,然后再复制数据到table1,但是有时会遇到Cannot allocate memory,然后导致整个服务器崩溃(是不是这个json数组太大,占了巨量的内存)。PS:已经在php.ini里将memory limit加到64M了(但总觉得治标不治本,这么一个复制过程,不需要那么多内存,关键还是代码不合理)。

require dirname(__FILE__) . '/../connection.php';<br />
mysql_select_db("news",$connextion);<br />
mysql_query("SET NAMES utf8");<br />
$query = mysql_query("SELECT * FROM temp_t where mykey = '1'");<br />
$jon = array();<br />
while($rows = mysql_fetch_array($query)){<br />
	$jon['a'] = $rows['id'];<br />
	$jon['b'] = $rows['title'];<br />
	$jon['c'] = $rows['content'];<br />
	$jon['d'] = $rows['date'];<br />
	$pjon .= json_encode($jon).',';<br />
}<br />
mysql_close($connextion);<br />
$njso = json_decode('['.substr($pjon,0,-1).']');<br />
foreach($njso as $nx){	<br />
	if($nx->a){<br />
		require dirname(__FILE__) . '/../connection.php';<br />
		mysql_select_db("news",$connextion);<br />
		mysql_query("SET NAMES utf8");<br />
		mysql_query("UPDATE temp_t SET mykey='2' WHERE id='".mysql_real_escape_string($nx->a)."'");<br />
		mysql_query("INSERT INTO table1 (id,title,content,date) values ('".mysql_real_escape_string($nx->a)."','".mysql_real_escape_string($nx->b)."','".mysql_real_escape_string($nx->c)."','".mysql_real_escape_string($nx->d)."'");<br />
		mysql_close($connextion);<br />
	}<br />
}
Copy after login


所以求助大虾们,有没有更节省的代码用来复制表的信息?要求mysql连接时间短,内存消耗又少?谢谢大家。

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

Undress AI Tool

Undress AI Tool

Undress images for free

Clothoff.io

Clothoff.io

AI clothes remover

Video Face Swap

Video Face Swap

Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

MySQL: An Introduction to the World's Most Popular Database MySQL: An Introduction to the World's Most Popular Database Apr 12, 2025 am 12:18 AM

MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables.

MySQL's Place: Databases and Programming MySQL's Place: Databases and Programming Apr 13, 2025 am 12:18 AM

MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen

How to connect to the database of apache How to connect to the database of apache Apr 13, 2025 pm 01:03 PM

Apache connects to a database requires the following steps: Install the database driver. Configure the web.xml file to create a connection pool. Create a JDBC data source and specify the connection settings. Use the JDBC API to access the database from Java code, including getting connections, creating statements, binding parameters, executing queries or updates, and processing results.

Why Use MySQL? Benefits and Advantages Why Use MySQL? Benefits and Advantages Apr 12, 2025 am 12:17 AM

MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions.

How to start mysql by docker How to start mysql by docker Apr 15, 2025 pm 12:09 PM

The process of starting MySQL in Docker consists of the following steps: Pull the MySQL image to create and start the container, set the root user password, and map the port verification connection Create the database and the user grants all permissions to the database

MySQL's Role: Databases in Web Applications MySQL's Role: Databases in Web Applications Apr 17, 2025 am 12:23 AM

The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.

Laravel Introduction Example Laravel Introduction Example Apr 18, 2025 pm 12:45 PM

Laravel is a PHP framework for easy building of web applications. It provides a range of powerful features including: Installation: Install the Laravel CLI globally with Composer and create applications in the project directory. Routing: Define the relationship between the URL and the handler in routes/web.php. View: Create a view in resources/views to render the application's interface. Database Integration: Provides out-of-the-box integration with databases such as MySQL and uses migration to create and modify tables. Model and Controller: The model represents the database entity and the controller processes HTTP requests.

How to install mysql in centos7 How to install mysql in centos7 Apr 14, 2025 pm 08:30 PM

The key to installing MySQL elegantly is to add the official MySQL repository. The specific steps are as follows: Download the MySQL official GPG key to prevent phishing attacks. Add MySQL repository file: rpm -Uvh https://dev.mysql.com/get/mysql80-community-release-el7-3.noarch.rpm Update yum repository cache: yum update installation MySQL: yum install mysql-server startup MySQL service: systemctl start mysqld set up booting

See all articles