在linux下面使用mysql,由于一开始建库的时候没有做好mysql问价的配置,结果导致所有的表使用一个表空间,导致ibdata1文件在不到半年时间里面变为30G直接导致mysql服务无法启动,应该在/etc/my.cnf文件的[mysqld]里面添加 innodb_file_per_table=1即mysql的
在linux下面使用mysql,由于一开始建库的时候没有做好mysql问价的配置,结果导致所有的表使用一个表空间,导致ibdata1文件在不到半年时间里面变为30G直接导致mysql服务无法启动,应该在/etc/my.cnf文件的[mysqld]里面添加 innodb_file_per_table=1即mysql的表使用单独的表空间。
innodb_file_per_table=1
innodb_file_per_table=0
值为1时表示使用单独的表空间,值为0是表示使用共享的表空间。
由于楼主在发现这个问题的时候mysql服务已经起不起来了,所以在配置文件里面添加了innodb_force_recovery=6命令。然后启动起来mysql服务,后来备份了数据库,然后从新建库,现在ibdata1文件只有10几M。
## innodb_force_recovery
## 可以设置为6个非零值:1~6。大的数字包含了前面所有小数字的影响,具体情况如下。
#1(SRV_FORCE_IGNORE_CORRUPT):忽略检查到的corrupt页。
#2(SRV_FORCE_NO_BACKGROUND):阻止主线程的运行,如主线程需要执行full purge操作,会导致crash。
#3(SRV_FORCE_NO_TRX_UNDO):不执行事务回滚操作。
#4(SRV_FORCE_NO_IBUF_MERGE):不执行插入缓冲的合并操作。
#5(SRV_FORCE_NO_UNDO_LOG_SCAN):不查看撤销日志(Undo Log),InnoDB存储引擎会将未提交的事务视为已提交。
#6(SRV_FORCE_NO_LOG_REDO):不执行前滚的操作

ACID attributes include atomicity, consistency, isolation and durability, and are the cornerstone of database design. 1. Atomicity ensures that the transaction is either completely successful or completely failed. 2. Consistency ensures that the database remains consistent before and after a transaction. 3. Isolation ensures that transactions do not interfere with each other. 4. Persistence ensures that data is permanently saved after transaction submission.

MySQL is not only a database management system (DBMS) but also closely related to programming languages. 1) As a DBMS, MySQL is used to store, organize and retrieve data, and optimizing indexes can improve query performance. 2) Combining SQL with programming languages, embedded in Python, using ORM tools such as SQLAlchemy can simplify operations. 3) Performance optimization includes indexing, querying, caching, library and table division and transaction management.

MySQL uses SQL commands to manage data. 1. Basic commands include SELECT, INSERT, UPDATE and DELETE. 2. Advanced usage involves JOIN, subquery and aggregate functions. 3. Common errors include syntax, logic and performance issues. 4. Optimization tips include using indexes, avoiding SELECT* and using LIMIT.

MySQL is an efficient relational database management system suitable for storing and managing data. Its advantages include high-performance queries, flexible transaction processing and rich data types. In practical applications, MySQL is often used in e-commerce platforms, social networks and content management systems, but attention should be paid to performance optimization, data security and scalability.

The relationship between SQL and MySQL is the relationship between standard languages and specific implementations. 1.SQL is a standard language used to manage and operate relational databases, allowing data addition, deletion, modification and query. 2.MySQL is a specific database management system that uses SQL as its operating language and provides efficient data storage and management.

InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.

Key metrics for EXPLAIN commands include type, key, rows, and Extra. 1) The type reflects the access type of the query. The higher the value, the higher the efficiency, such as const is better than ALL. 2) The key displays the index used, and NULL indicates no index. 3) rows estimates the number of scanned rows, affecting query performance. 4) Extra provides additional information, such as Usingfilesort prompts that it needs to be optimized.

Usingtemporary indicates that the need to create temporary tables in MySQL queries, which are commonly found in ORDERBY using DISTINCT, GROUPBY, or non-indexed columns. You can avoid the occurrence of indexes and rewrite queries and improve query performance. Specifically, when Usingtemporary appears in EXPLAIN output, it means that MySQL needs to create temporary tables to handle queries. This usually occurs when: 1) deduplication or grouping when using DISTINCT or GROUPBY; 2) sort when ORDERBY contains non-index columns; 3) use complex subquery or join operations. Optimization methods include: 1) ORDERBY and GROUPB


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