<p>MySQL raises this error when the comment defined for a table partition exceeds the maximum permitted length.</p>
<p>MySQL Error 1793: ER_TOO_LONG_TABLE_PARTITION_COMMENT appears when a partition comment is longer than the server’s allowed size. Shorten or remove the PARTITION COMMENT to resolve the issue.</p>
Comment for table partition '%s' is too long (max = %lu)
MySQL throws error 1793 with SQLSTATE HY000 when the comment attached to a table partition is too long. The server checks the length of the COMMENT clause during CREATE TABLE or ALTER TABLE operations and blocks the statement if the byte count exceeds the internal limit.
This safeguard ensures the data dictionary stays within size bounds and remains performant. Because partition metadata is stored with every partition definition, excessively long comments can bloat dictionary storage and hurt performance.
The primary trigger is a PARTITION definition containing a COMMENT string that exceeds the length compiled into the MySQL source (typically 1024 characters). Any attempt to create or modify a partition with a longer comment value will fail immediately.
The error can also surface indirectly when a DDL generator or ORM tool adds descriptive text without validating its length, or when concatenated variables expand beyond the limit during deployment scripts.
The fastest remedy is to shorten the COMMENT text to at most 1024 characters. Review the intended description, remove unneeded prose, and apply the corrected DDL.
If long documentation is required, store it in a separate metadata table instead of the partition definition. Then reference that table in application code or documentation portals.
Automated migrations - Update the migration template to truncate or omit overly long partition comments before executing.
Copy-paste from spec documents - Replace line breaks and redundant wording. Aim for concise labels that fit within the limit.
Version-controlled DDL files - Add a unit test or linter rule that asserts COMMENT length to catch violations during CI.
Define a maximum comment length constant (e.g., 512 characters) in your team's DDL guidelines. Document the limit in coding standards so developers know the boundary.
Automate schema reviews with a Galaxy SQL Collection linter that flags partition comments exceeding the agreed size, preventing the error from ever reaching production.
Errors 1064 (syntax error) and 1113 (incorrect table definition) often occur during the same DDL run when comment strings are malformed. Address those by validating syntax and data types alongside comment length.
The defined COMMENT string simply contains more characters than MySQL allows for partition metadata.
Multi-byte UTF-8 characters inflate the byte length beyond the expected character count.
A tool automatically inserts verbose documentation without enforcing MySQL’s size restriction.
Deployment scripts merge environment strings that push the comment past the safe threshold.
Raised when the CREATE TABLE or ALTER TABLE statement defines more partitions than the server limit.
Occurs if the COMMENT clause is placed in an invalid position or contains illegal characters.
Thrown when a subpartition option conflicts with the partition definition.
No. The limit is hard-coded in the MySQL source and cannot be modified via configuration.
MySQL counts bytes, not characters. Multi-byte characters reduce the maximum visible length.
No. The COMMENT is metadata only and does not affect query logic or performance.
Galaxy’s SQL editor highlights DDL limits and can lint COMMENT length before you run the statement, preventing the error.
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