Once after updating the ABillS billing system, when opening the Maintenance>Hardware>PON menu and selecting a device, an SQL error occurred:
One day I noticed warnings in the MySQL logs:
Once it was necessary to make a record in the table very quickly and I quickly wrote a SQL query, but after executing it I got an error:Continue reading “Solution for error 21S01 Column count doesn’t match value count at row 1”
Once on Ubuntu Server 18.04 I upgraded Zabbix 4.4 to 5.0 and found an error in the logs during the upgrade:Continue reading “Solution: Specified key was too long; max key length is 767 bytes”
innodb_flush_method defines the method for flushing data from RAM to disk.Continue reading “How to change innodb_flush_method in MySQL”
Once I created a raid, mounted it as a disk system partition and transferred the MySQL directory directly to it, but in this case there were drawbacks, the lost+found directory could appear, it could not be used for other data, etc., after that I began to transfer the MySQL directory not directly to the partition, but created a directory on it and transferred it to it.Continue reading “Migrating MySQL Directory”
innodb_io_capacity – determines the number of write IOPS for background InnoDB tasks, such as flushing pages from a buffer pool, etc. If the cleanup operation is lagging, then InnoDB can perform cleanup more aggressively at a higher IOPS, which is defined in the innodb_io_capacity_max variable.Continue reading “How to change innodb_io_capacity in MySQL”
Partitioning tables in MySQL is splitting a large table into parts according to the specified criteria, which will speed up reading and writing data to it if this table contains a very large amount of data.Continue reading “Partitioning tables in MySQL”
innodb_stats_on_metadata – Lets you collect statistics on metadata operations such as SHOW TABLE STATUS when accessing INFORMATION_SCHEMA.TABLES or INFORMATION_SCHEMA.STATISTICS tables.
In newer versions of MySQL, the innodb_stats_on_metadata parameter is disabled by default, which makes working with these tables faster.
When creating a table, the ENGINE option is used, which specifies the storage engine, if this option is not specified in the SQL query, then the default storage engine is used, which is specified in the MySQL server configuration file or when it starts mysqld –default-storage-engine=InnoDB.Continue reading “How to change default-storage-engine in MySQL”