MySQL Configuration Parameters FAQ

MySQL installation of the initial installation, the longest encountered problem is the configuration parameter compatibility problem, because the database parameters have changed, resulting in the database is not recognized the situation is very troublesome, fortunately there are official documentation guidelines, to solve such problems occur

Currently widely used in mysql5.5 and above, here is 5.6 For example, contains all the parameters used in the mysql5.6:

Http://dev.mysql.com/doc/refman/5.6/en/mysqld-option-tables.html

For example, the following error:

[Warning] TIMESTAMP with implicit the DEFAULT value is deprecated. --explicit_defaults_for_timestamp server option (see documentation for more details).

The warning indicates that the parameter used to be implicitly the default value, but deprecated in the new version, requires that the configuration parameter Explicit_defaults_for_timestamp be explicitly added at configuration or start-up.

View the official website explanation:

1. mysql timestamp column if no explicit declaration is empty, the timestamp column is assigned to a non-empty property. (Columns of other data types, such as those that do not have explicit declarations that are not empty, are allowed to be empty) that is, when the column is set to NULL, the default is converted to the current timestamp.

2, when timestamp as the first column in the table, such as not declared as empty, explicit default and on update clauses. is automatically assigned to the default Current_timestamp and on Update current_timestamp properties.

3. When the timestamp column is the second column in the table, if it is not declared empty, the default clause is automatically assigned as default ' 0000-00-00 00:00:00 ' (' 0 ' timestamp). For rows that do not specify a specific timestamp, the column automatically assigns a zero timestamp and does not produce a warning.

These non-standard behaviors remain as the default timestamp rules until 5.6. Version 6 is deprecated, so when you initialize the database with the above warning message, you can change the non-standard behavior by specifying the Explicit_defaults_for_timestamp parameter.

Explicit_defaults_for_timestamp Takes a Boolean (Boolean) value, which defaults to false, and can be configured to explicitly open arguments in file my.cnf

Explicit_defaults_for_timestamp=true

In version 5.1 of the innodb_file_io_threads parameter, set the number of MySQL InnoDB engine I/O threads, version 5.1 uses InnoDB plugin when innodb_read_io_threads and innodb_ The write_io_threads parameter is replaced by the 5.6 version, and the Innodb_file_io_threads parameter is canceled by using both parameters directly.

Innodb_read_io_threads the default value of 4, the minimum value of 1, and the maximum value of 64.

This article is from the "linuxoracle" blog, make sure to keep this source http://onlinekof2001.blog.51cto.com/3106724/1629665

MySQL Configuration Parameters FAQ