Assess and adjust SQL instance flags

[jan-meyer-1986]

A range of flages to adjusted were suggested:

max_join_size // useful for denying execution of outright stupid queries like large cross-joins.
    key_buffer_size, join_buffer_size, innodb_buffer_pool_size // optimal sizes depend on available RAM. I am mentioning it just to make sure it is not left at the default values
    max_allowed_packet = 10M // important for imports with long rows. You might have already encountered this limit
    sql_mode // I think I was disabling some of MySQL shenanigans and making it more ANSI compatible.
    wait_timeout, lock_wait_timeout, max_execution_time // consider decreasing these default values to improve availability of the server for the public

---

The following list shows them with their current (default) values:

'max_join_size', '18446744073709551615'

'key_buffer_size', '8388608'
'join_buffer_size', '262144'
'innodb_buffer_pool_size', '2550136832'

'max_allowed_packet', '33554432'

'sql_mode', 'ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION'

'wait_timeout', '28800'
'lock_wait_timeout', '31536000'
'max_execution_time', '0'

[jan-meyer-1986]

https://dev.mysql.com/doc/refman/8.0/en/sql-mode.html#sqlmode_ansi

This sql_mode seems tailored for ANSI compatibility

[jan-meyer-1986]

https://releem.com/docs/mysql-performance-tuning/key_buffer_size

The key_buffer_size variable is used with the MyISAM storage engine in earlier versions of MySQL. InnoDB replaced MyISAM starting with MySQL 5.5. This variable can be set very low if you do not use MyISAM within your servers.

When key_buffer_size is increased more memory is allocated for the MySQL index buffer. More memory means less reliance on disk I/O and improved performance. For server situations still using MyISAM, set this value at 25 to 30% of available memory.

[jan-meyer-1986]

https://releem.com/docs/mysql-performance-tuning/join_buffer_size

1% of RAM -> 60MB

[jan-meyer-1986]

https://releem.com/docs/mysql-performance-tuning/innodb_buffer_pool_size

Seems pretty important.

< than 80% of RAM

current default value: 39.6%

needs observation during usage

[jan-meyer-1986]

https://releem.com/docs/mysql-performance-tuning/max_allowed_packet

default value of 32MB seems okay. hard to tell whether to change or not.