1939
MariaDBERRORNotableDDLHIGH confidence
The total length of the partition expression is too long
Production Risk
Low — DDL is rejected.
What this means
The combined key length of the columns used in a COLUMNS partitioning definition exceeds the maximum allowed key length (typically 3072 bytes for InnoDB).
Why it happens
- 1Selecting too many large VARCHAR or CHAR columns in PARTITION BY RANGE COLUMNS or LIST COLUMNS.
How to reproduce
trigger — this will error
trigger — this will error
-- RANGE COLUMNS with very long VARCHAR columns exceeding key length limit
expected output
ERROR 1939 (HY000): The total length of the partition expression is too long.
Fix
Use shorter columns or fewer columns as the partitioning key
Use shorter columns or fewer columns as the partitioning key
-- Use a smaller prefix or choose integer/date columns for partitioning
Why this works
InnoDB enforces a maximum key length; reduce the combined byte length of partitioning columns.
Sources
Official documentation ↗
MySQL 8.0 — 1939 ER_PARTITION_FIELDS_TOO_LONG2
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