When using Composer in a production environment, you need to pay attention to safety, stability and performance. 1. Use composerinstall-no-dev to reduce unnecessary development dependencies and reduce online environment risks; 2. Always submit and rely on composer.lock files to ensure version consistency, and avoid using updates during deployment; 3. Optional configuration platform-check=false ignores platform differences warnings, which is suitable for building packaging scenarios; 4. Enable APCU to accelerate automatic loading to improve performance, especially suitable for high concurrency services, while paying attention to namespace uniqueness to avoid cache conflicts.

MySQL supports transaction processing, and uses the InnoDB storage engine to ensure data consistency and integrity. 1. Transactions are a set of SQL operations, either all succeed or all fail to roll back; 2. ACID attributes include atomicity, consistency, isolation and persistence; 3. The statements that manually control transactions are STARTTRANSACTION, COMMIT and ROLLBACK; 4. The four isolation levels include read not committed, read submitted, repeatable read and serialization; 5. Use transactions correctly to avoid long-term operation, turn off automatic commits, and reasonably handle locks and exceptions. Through these mechanisms, MySQL can achieve high reliability and concurrent control.

Character set and sorting rules issues are common when cross-platform migration or multi-person development, resulting in garbled code or inconsistent query. There are three core solutions: First, check and unify the character set of database, table, and fields to utf8mb4, view through SHOWCREATEDATABASE/TABLE, and modify it with ALTER statement; second, specify the utf8mb4 character set when the client connects, and set it in connection parameters or execute SETNAMES; third, select the sorting rules reasonably, and recommend using utf8mb4_unicode_ci to ensure the accuracy of comparison and sorting, and specify or modify it through ALTER when building the library and table.

The most direct way to connect to MySQL database is to use the command line client. First enter the mysql-u username -p and enter the password correctly to enter the interactive interface; if you connect to the remote database, you need to add the -h parameter to specify the host address. Secondly, you can directly switch to a specific database or execute SQL files when logging in, such as mysql-u username-p database name or mysql-u username-p database name

The setting of character sets and collation rules in MySQL is crucial, affecting data storage, query efficiency and consistency. First, the character set determines the storable character range, such as utf8mb4 supports Chinese and emojis; the sorting rules control the character comparison method, such as utf8mb4_unicode_ci is case-sensitive, and utf8mb4_bin is binary comparison. Secondly, the character set can be set at multiple levels of server, database, table, and column. It is recommended to use utf8mb4 and utf8mb4_unicode_ci in a unified manner to avoid conflicts. Furthermore, the garbled code problem is often caused by inconsistent character sets of connections, storage or program terminals, and needs to be checked layer by layer and set uniformly. In addition, character sets should be specified when exporting and importing to prevent conversion errors

To install the Composer plug-in, please first confirm that Composer is installed and the composer.json file exists, and then follow the following steps: 1. Make sure that Composer has been installed and created composer.json; 2. Search and copy the required plug-in name on Packagist; 3. Use the composerrequirequire command to install the plug-in, such as composerrequiredealerdirect/phpcodesniffer-composer-installer; 4. Verify whether the plug-in is effective and check compatibility and configuration. Follow these steps to correctly install the Composer plug-in.

To design a reliable MySQL backup solution, 1. First, clarify RTO and RPO indicators, and determine the backup frequency and method based on the acceptable downtime and data loss range of the business; 2. Adopt a hybrid backup strategy, combining logical backup (such as mysqldump), physical backup (such as PerconaXtraBackup) and binary log (binlog), to achieve rapid recovery and minimum data loss; 3. Test the recovery process regularly to ensure the effectiveness of the backup and be familiar with the recovery operations; 4. Pay attention to storage security, including off-site storage, encryption protection, version retention policy and backup task monitoring.

To improve Apache performance, optimize configuration parameters are required. 1. Adjust KeepAlive parameters: Enable MaxKeepAliveRequests and set to 500 or higher, and set KeepAliveTimeout to 2~3 seconds to reduce connection overhead. 2. Configure the MPM module: Set StartServers, MinSpareServers, MaxSpareServers and MaxClients in prefork mode; set ThreadsPerChild and MaxRequestWorkers in event or worker mode to avoid excessive load. 3. Control memory usage: based on the memory usage of a single process