information_schema在mysql8.0之后有缓存,数据不是最新的,可以通过以下获取最新的统计数据 ANALYZETABLE`your_table`;
OPTIMIZE TABLE 可以在线DDL,通过指定(ALGORITHM=INPLACE) ,不过这个只支持INNODB表,普通表和分区表都是支持的.表重建的方式有两种,OPTIMIZE TABLE 和 ALTER TABLE ... FORCE两种方式都可以触发表重建. OPTIMIZE TABLE 也有适用于 ALGORITHM=COPY的一些条件: 1:当old_alter_table参数设置为ON的时候,OPTIMIZE并不会重...
By default, OPTIMIZE TABLE does not work for tables created using any other storage engine and returns a result indicating this lack of support. You can make OPTIMIZE TABLE work for other storage engines by starting mysqld with the --skip-new option. In this case, OPTIMIZE TABLE is just ma...
这意味着在运行optimize table语句时，可以同时执行读写操作，而不会锁定整个表。通过命令行操作是一种在...
OPTIMIZE TABLE schema.my_parent_table; ALTER TABLE schema.my_parent_table ADD back all indexes and foreign keys … SET FOREIGN_KEY_CHECKS = ON; All of the above works except for the optimize itself (I verified). I get “Error 1025 … Error on rename of … (errno: 150)” because of...
目前支持optimize命令的引擎有MyISAM, InnoDB, and ARCHIVE,对于InnoDB,会将optimize命令映射为ALTER TABLE命令,该命令会重建数据表,更新索引统计信息、回收主键索引中空间。 3. InnoDB 和 MyISAM 如果你的MySQL是有备库的,如果你只希望在主库上执行的话,那么可以加上关键字NO_WRITE_TO_BINLOG(或者LOCAL,意思完全...
Name OPTIMIZE TABLE Synopsis OPTIMIZE [LOCAL|NO_WRITE_TO_BINLOG] TABLE table[, ...] Use this statement to optimize the data contained in a table. Optimization is useful when many rows have been deleted … - Selection from MySQL in a Nutshell, 2nd Editio
OPTIMIZE TABLE reorganizes the physical storage of table data and associated index data, to reduce storage space and improve I/O efficiency when accessing the table. The exact changes made to each table depend on the storage engine used by that table. ...
1. Run optimize table against your tables This command defragments a table after you have deleted a lot of rows from it. 2. Use insert delayed when you do not need instant gratification - a response instantly - when your data is written. This reduces the overall insertion impact because...
OPTIMIZE will rebuild the table so that all (except last) blocks are mostly full. This can lead to a net of freeing some blocks. Your before/after stats imply that no extra blocks could be freed up. If you are running all InnoDB, you could (should) set innodb_buffer_pool_size higher...