The server cannot recognize the system variable named in the statement, usually during SET or SELECT @@ operations.
MySQL Error 1193: ER_UNKNOWN_SYSTEM_VARIABLE occurs when you try to read or set a system variable that the running MySQL version does not recognize. Verify the variable spelling, server version, and scope, then use SHOW VARIABLES or upgrade the server to resolve the error.
Unknown system variable '%s'
Error 1193 fires when MySQL encounters a variable name it does not know. The message reads: Unknown system variable 'var_name'. It appears in SET, SELECT @@, or configuration files.<\/p>
The issue blocks session initialization scripts, replication, and startup because MySQL treats unknown variables as fatal. Fixing it quickly restores application connectivity and automation jobs.<\/p>
Using a variable introduced in a newer MySQL release is the top trigger.
A client script may run against an older server that lacks that variable.<\/p>
Typos, wrong letter case, or missing underscores also lead to the error because MySQL performs case-insensitive but exact-spelling checks.<\/p>
Start by verifying the variable list with SHOW GLOBAL VARIABLES LIKE '%var_name%';.
If nothing matches, confirm the server version supports the variable by reading the documentation.<\/p>
When the variable is valid but unsupported in your version, upgrade MySQL or remove the setting. For typos, correct the spelling and rerun the statement.<\/p>
Replication scripts often set binlog_format or log_bin_trust_function_creators on older replicas, producing Error 1193. Upgrade replicas or guard the SET statement with version checks.<\/p>
Docker images that embed my.cnf from a newer distro can fail at startup.
Edit the file to remove unsupported variables before container build.<\/p>
Always test configuration files with mysqld --verbose --help inside CI to catch unknown variables early.<\/p>
Use SHOW VARIABLES output from the target instance to parameterize automation scripts so they never reference missing variables.<\/p>
Error 1192 (ER_CANT_FIND_SYSTEM_REC): occurs when MySQL cannot locate a system database table.
The fix is running mysql_upgrade.<\/p>
Error 1231 (ER_WRONG_ARGUMENTS): appears when a variable receives an invalid value. Validate value ranges to resolve.<\/p>.
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