Still waters run deep

摘要： Q:I read from many places that disabling index before loading a data table can significantly speed up the importing process. But innodb does not support "disable index". Particularly, I got a warning message after runningALTERTABLE mytable DISABLE KEYS;+-------+------+--------------------- 阅读全文

摘要： Q:I'm ready to move from MyISAM to InnoDB but wanted to know if there was a full list of things to look for? For example, I haven't seen any list mention that running DISABLE KEYS on an InnoDB table will throw a warning, except the manual page for ALTER TABLE. It's that kind of thing I n 阅读全文

摘要： Q:I read the following on this pagehttp://dev.mysql.com/doc/mysql/en/server-system-variables.htmlbulk_insert_buffer_size MyISAM uses a special tree-like cache to make bulk inserts faster for INSERT ... SELECT, INSERT ... VALUES (...), (...), ..., and LOAD DATA INFILE. This variable limits the size o 阅读全文

摘要： delay_key_writeThis option applies only to MyISAM tables. It can have one of the following values to affect handling of the DELAY_KEY_WRITE table option that can be used in CREATE TABLE statements.If DELAY_KEY_WRITE is enabled for a table, the key buffer is not flushed for the table on every index u 阅读全文

摘要： There have been a few posts by Sheeri and Baron today on the MySQL sort_buffer_size variable. I wanted to add some more information about this buffer, what is impacted when it is changed, and what to do about it?The first thing you need to know is the sort_buffer_size is a per session buffer. That i 阅读全文

摘要： Q:I am MySQL on server with 6GB RAM. I need to know what is the difference between myisam_sort_buffer_size and sort_buffer_size?I have following size set to them:myisam_sort_buffer_size = 8Msort_buffer_size = 256MPlease also mention if these values are fine or need adjustments?ThanksA:sort_buffer_si 阅读全文

摘要： Share nothing理论在数据库设计和优化中的实践应用 首先介绍share nothing概念。最早接触它是在 DataBaseManagentSystem一书的并行数据库章节中。 并行数据库要求尽可能的去并行执行数据库操作，从而提高性能。在并行计算体系结构实现中有很多可选的体系结构。包括： share-memory：多个cpu共享同一片内存，cpu之间通过内部通讯机制（interconnection network）进行通讯； share-disk ：　每一个cpu使用自己的私有内存区域，通过内部通讯机制直接访问所有磁盘系统。 Share-nothing： 每一个cpu都有私... 阅读全文

摘要： This function returns a string result with the concatenated non-NULLvalues from a group. It returnsNULLif there are no non-NULLvalues. The full syntax is as follows:GROUP_CONCAT([DISTINCT] expr [,expr ...] [ORDER BY {unsigned_integer | col_name | expr} [ASC | DESC] [,col_... 阅读全文

摘要： 1.环境Mysql主从Mysql版本：5.1.49-log系统：RedHatEnterpriseLinuxServerrelease5.464bit2.表面现象数据库操作变慢，如用主键作为条件查询，有时也会超过1秒；主库IO使用率一直在90%以上（平常io比较低20%以内），dirty页占总数的90%左右，脏页刷不完；持续了几个小时~3.从系统上看主库的iostat的使用率一直在90%以上，Mysqldata所在目录的大小一直没变；主库的ib_logfile20分钟切换一次（主库上面的innodblog写得还是比较频繁），而从库的ib_logfile4小时切换一次。4.从mysql上看在主库B 阅读全文

摘要： We receive this question about the ibdata1 file in MySQL very often inPercona Support.The panic starts when the monitoring server sends an alert about the storage of the MySQL server – saying that the disk is about to get filled.After some research you realize that most of the disk space is used by 阅读全文