MariaDB Observability Peter Zaitsev, CEO, Percona MariaDB Day Brussels February 2nd, 2020 Brussels, Belgium A SET statement that assigns variable values is not written to the binary log, so in replication scenarios it affects only the host on which you execute it. innodb_sync_spin_loops is a global variable. This is depreciated and even removed in MySQL 5.5. DECLARE Website VARCHAR(45); This example would declare a variable called Website as a VARCHAR(45) data type.. You can then later set or change the value of the Website variable, as follows:. It does not even accept 1000 but when I tried with the value of 500, it took it. When it comes to wait_timeout, yes, the session variable is set to 2880 while global variable is set to 86400. I have 3-node cluster. We can verify this by using the System Properties GUI for exploring environment variables: Press WINDOWS + X, then Y; In the System window, click the Change settings link; Setting a global variable to DEFAULT will restore it to the server default, and setting a session variable to DEFAULT will restore it to the current global value. "If you change a global system variable, the value is remembered and used for new connections until the server restarts. Today I performed testing on Galera Clustering with MariaDB 10.3.10. Hey Rick, yes, you were right. In order to have this parameter persistent, should I edit a configuration file? Also, you can specify using flags as --set-variable=var_name=value. Most options can be set using their actual names in the my.cnf. SET Website = 'CheckYourMath.com'; I have added a event to my mySQL db and it works fine, but the thing that is bothering me is that every now and then I have to set the mysql global variable to 1 so that my event is active.I log in as root user and have complete privileges (I use it for practice purpose) The following sections describe SET syntax for setting variables. set-variable=var_name=value is the classic method to do this in my.cnf. DEFAULT. The next time we log into the system, with the same user account, that environment variable will still be set. Examples. Would that file be C:\Program Files\MySQL\MySQL Server 5.5\my.ini? To affect all replication hosts, execute the statement on each host. Isn't the set command persistent? Earlier than MySQL 4.0.2, most configuration options were set using this method. MariaDB [(none)]> SET GLOBAL host_cache_size=autoset; ERROR 1232 (42000): Incorrect argument type to variable 'host_cache_size' There is special code to handle auto-sizing for this system variable (and others) at startup: The ‘update’ callback functions for several settable global InnoDB variables are acquiring InnoDB latches while holding LOCK_global_system_variables.. On the other hand, some InnoDB code is invoking THDVAR() while holding InnoDB latches. Example - Declaring a variable. Like SET GLOBAL, SET PERSIST is the command that can be used for updating the system variables at runtime and make them persistent across restarts. (To make a global system variable setting permanent, you should set it in an option file)" – mvmn Jan 21 '16 at 19:02 When we use the PERSIST keyword, the variable changes are updated to the mysqld-auto.cnf option file in the data directory. Below is an example of how to declare a variable in MariaDB called Website.. 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