3243
MariaDBWARNINGNotableQuery OptimizationHIGH confidence
Index cannot be used for this query
Production Risk
Low — warning only; query proceeds with a full scan instead.
How to reproduce
trigger — this will error
trigger — this will error
SELECT /*+ INDEX(t1 idx_col) */ * FROM t1 WHERE non_indexed_col = 1;
expected output
Warning 3243: Index 'idx_col' is not applicable for query.
Fix
Remove index hint
Remove index hint
SELECT * FROM t1 WHERE non_indexed_col = 1;
Why this works
Let the optimizer choose the best access path without forcing an inapplicable index.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 3243 ER_WARN_INDEX_NOT_APPLICABLE2
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