1659
MySQLERRORNotableInnoDBHIGH confidence
InnoDB full-text index limit reached
Production Risk
Low — the ALTER is rejected; existing indexes are unaffected.
What this means
The number of full-text indexes on a single InnoDB table has reached the maximum limit of 6.
Why it happens
- 1Attempting to create more than 6 full-text indexes on one InnoDB table.
How to reproduce
trigger — this will error
trigger — this will error
ALTER TABLE articles ADD FULLTEXT INDEX ft7 (col7); -- when 6 already exist
expected output
ERROR 1659 (HY000): Cannot create more than 6 full-text indexes on InnoDB table.
Fix
Combine columns into a single full-text index
Combine columns into a single full-text index
ALTER TABLE articles DROP INDEX ft6, DROP INDEX ft5, ADD FULLTEXT INDEX ft_combined (col5, col6, col7);
Why this works
Multi-column full-text indexes count as one, allowing more columns to be indexed within the limit.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 1659 ER_INNODB_FT_LIMIT
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