3159
MySQLWARNINGCriticalDeprecationHIGH confidence
Deprecated identifier used
Production Risk
Low — warning only; may cause errors on upgrade to a version where the identifier is removed.
What this means
A deprecated identifier (such as a system variable name, keyword, or built-in function name) was used. The identifier still works but will be removed in a future MySQL version.
Why it happens
- 1Using a renamed or deprecated system variable (e.g., query_cache_* variables after removal).
- 2Using deprecated keywords or function names.
How to reproduce
trigger — this will error
trigger — this will error
SET GLOBAL query_cache_size = 0; -- after query cache removal in 8.0
expected output
Warning (Code 3159): Deprecated identifier: 'query_cache_size'.
Fix
Remove references to the deprecated identifier
Remove references to the deprecated identifier
-- Remove query_cache_size and related settings from my.cnf
Why this works
Eliminates the warning and prepares for future version compatibility.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3159 ER_WARN_DEPRECATED_IDENT
Content generated with AI assistance and reviewed for accuracy. Found an error? hello@errcodes.dev