1765
MySQLERRORNotableDDLHIGH confidence
Too many key parts specified
Production Risk
Low — DDL rejected.
What this means
An index definition includes more key parts than the MySQL limit allows (16 columns per index).
Why it happens
- 1Creating an index with more than 16 columns.
How to reproduce
trigger — this will error
trigger — this will error
CREATE INDEX idx ON tbl (c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16,c17); -- 17 parts
expected output
ERROR 1765 (HY000): Too many key parts specified; max 16 parts allowed.
Fix
Reduce the number of columns in the index to 16 or fewer
Reduce the number of columns in the index to 16 or fewer
CREATE INDEX idx ON tbl (c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16);
Why this works
Stays within the 16-column-per-index hard limit.
What not to do
✕
Sources
Official documentation ↗
MySQL 8.0 — 1765 ER_TOO_MANY_KEY_PARTS_ERROR
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