比如数据库名或表名,列类型,访问权限(更加细化的访问方式) performance_schema 数据库 MySQL 5.5开始新增的数据库,主要用于收集数据库服务器性能参数,库里表的存储引擎均为PERFORMANCE_SCHEMA,用户不能创建存储引擎为PERFORMANCE_SCHEMA的表 sys 数据库 MySQL5.7之后新增加的数据库,库中所有数据源来自performance_schema。
'.',table_name), table_schema,table_name,ENGINE, sum(data_length/1024/1024) as data_mb , sum(index_length/1024/1024) as index_mb, sum((data_length+index_length)/1024/1024) as all_mb, sum(table_rows) from information_schema.tables where table_schema not in('mysql','performance_sche...
FORCE or OPTIMIZE TABLE to defragment tables for better performance ALTER TABLE `crmdb`.`el_crm_history` FORCE; -- can free 114 MiB Total freed space after defragmentation: 114 MiB 230 CVE(s) found for your MySQL release. Consider upgrading your version ! Configure your accounts with ip or...
CSV. The command recognizes the storage engine, but there are no significant performance improvements. Archive. The command compresses the table into a smaller and compact format. Tip 2: Optimize Multiple Tables at Once To optimize multiple tables at once, use: OPTIMIZE TABLE [table_name_1], ...
优化表使用OPTIMIZE TABLE语句。只能优化表中的VARCHAR,BLOB,TEXT类型的字段。OPTIMIZE TABLE语句可以消除删除和更新造成的磁盘碎片,从而减少空间浪费。因为如果一个表使用了TEXT或者BLOB这样的数据类型,那么更新,删除等操作就 会造成磁盘空间的浪费。因为,更新和删除操作以后,以前分配的磁盘空间不会自动回收。使用OPTIMIZE ...
为了获得更理想的使用效果,大家可以在变更表格模式(包括添加、删除索引或者执行其它重要变更)后在某一台MySQL服务器中运行OPTIMIZE TABLE <tab-name>。 在实际使用环境中的测试结果显示,AQL能够将大量查询事务的整体效率提升70倍。在测试中,一套网络内容存储管理系统中包含有十一套复杂表格,在对其进行正常查询时,整个流...
这个锁的作用范围更广,这个锁会阻止文件的创建,重命名,删除,包括 REPAIR TABLE TRUNCATE TABLE, OPTIMIZE TABLE操作以及账户的管理都会被阻塞。当然这些操作对于内存临时表来说是可以执行的,为什么内存表不受这些限制呢?因为内存表不需要备份,所以也就没必要满足这些条件。
[OK] InnoDB log waits: 0 --- Recommendations --- General recommendations: Run OPTIMIZE TABLE to defragment tables for better performance Enable the slow query log to troubleshoot bad queries Variables to adjust: query_cache_limit (> 1M, or use smaller result sets) MySQLTuner offers suggestions...
| performance_schema_max_program_instances | -1 | | profiling | OFF | | profiling_history_size | 15 | | protocol_version | 10 | | proxy_user | | | sha256_password_proxy_users | OFF | | slave_compressed_protocol | OFF | | stored_program_cache | 256 | ...
Performance issues are often stubborn things to cure. Suddenly a query or operation seems slow, or slower-ish. Sadly, the database is often pointed at as the culprit by developers who are either positive their code cannot be at fault or those who see dat