Planet MySQL Planet MySQL: Meta Deutsch Español Français Italiano 日本語 Русский Português 中文
Showing entries 1 to 2

Displaying posts with tag: dynamic variables (reset)

Contradiction for the Day
+1 Vote Up -0Vote Down

Today’s contradiction:

MySQL has server variables named new and old.

The new variable can be set per-session and globally, and is dynamic. The old variable is not dynamic, and only global in scope. Both default to FALSE in MySQL 5.1.

According to the manual, the new variable:

was used in MySQL 4.0 to turn on some 4.1 behaviors, and is retained for backward compatibility.

That same page notes the following about the old variable:

…  [Read more...]
SHOW VARIABLES Shows Variables MySQL Does Not Know About
+0 Vote Up -0Vote Down

The listing of Dynamic System Variables on the MySQL Reference Manual’s page is supposed to show those variables you can change on-the-fly. innodb_data_home_dir is listed there as a dynamic variable, but it is not one, and trying to change it on-the-fly doesn’t work:

mysql> set global innodb_data_home_dir="/data/mysql/data"; ERROR 1193 (HY000): Unknown system variable 'innodb_data_home_dir'

mysql> set session innodb_data_home_dir="/data/mysql/data"; ERROR [...]

Showing entries 1 to 2

Planet MySQL © 1995, 2016, Oracle Corporation and/or its affiliates   Legal Policies | Your Privacy Rights | Terms of Use

Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily represent the opinion of Oracle or any other party.