MySQL throws ER_TOO_MANY_KEYS when a CREATE or ALTER TABLE statement defines more indexes than the server’s maximum (usually 64).
MySQL Error 1069: ER_TOO_MANY_KEYS appears when a table definition contains more than the allowed number of indexes (default 64). Drop redundant indexes or redesign composites, then run ALTER TABLE to resolve the issue.
Too many keys specified; max %d keys allowed
The exact message is: “Too many keys specified; max 64 keys allowed”. MySQL raises it during CREATE TABLE or ALTER TABLE when the definition includes more secondary indexes than the server limit.
The cap protects engine metadata and performance.
As soon as the parser counts index definitions above the limit, execution stops and Error 1069 is returned with SQLSTATE 42000.
Exceeding the hard cap of 64 (MySQL 8.0) or 16 (very old versions) index definitions triggers the error.
Each PRIMARY KEY, UNIQUE, INDEX, FULLTEXT, and foreign-key-backed index counts toward the total.
ORM migrations, automated schema generators, or incremental ALTER statements can silently add indexes until the table hits the ceiling and the next addition fails.
First list existing indexes with SHOW INDEX FROM your_table. Remove duplicates or unused ones using ALTER TABLE DROP INDEX.
Consolidate single-column indexes into multi-column composites that satisfy multiple queries.
If you genuinely need many indexes, consider partitioning or moving seldom-queried columns into a separate table. Upgrading from MySQL 5.6/5.7 (limit 64) will not help because the ceiling remains, so schema refactor is usually required.
Foreign-key heavy EAV schemas often autogenerate dozens of single-column indexes.
Dropping low-selectivity keys or switching to composite indexes removes the blockade.
Django or Laravel migrations that add an index per foreign key can hit the limit. Edit the migration to create only the indexes you query on, then rerun.
Design an index strategy early, matching actual query patterns.
Use EXPLAIN to prove an index’s value before adding it.
Galaxy’s IDE lists current indexes alongside queries, letting teams discuss, approve, and version changes, preventing unchecked index growth.
Error 1070 ER_TOO_MANY_KEY_PARTS occurs when a single composite index has too many columns. Fix by reducing column count per key.
Error 1118 Row size too large arises when too many VARCHAR/TEXT columns increase row length. Refactor wide tables or use normalization.
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MySQL 5.7 and 8.0 allow a maximum of 64 indexes per table. Any definition over this count triggers Error 1069 immediately.
Each FOREIGN KEY automatically spawns an index.
Developers may not realize the accumulation until the limit is reached.
Frameworks like Hibernate, Django, and Rails often create one index per reference column, quickly exhausting the quota in large schemas.
Teams sometimes add overlapping single-column indexes instead of designing strategic composite keys, inflating the total.
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In MySQL 5.6, 5.7, and 8.0 the hard limit is 64 indexes per table, regardless of storage engine. Older versions allowed fewer.
Yes. The PRIMARY KEY is one of the indexes and is included in the total count.
No. The limit is coded in the server source and cannot be changed via configuration parameters.
Galaxy surfaces existing indexes next to your DDL, supports version control, and lets teams endorse optimized schemas, stopping runaway index growth before deployment.
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