<p>The table comment exceeds MySQL’s maximum allowed length, triggering error 1628 during CREATE or ALTER TABLE.</p>
<p>MySQL Error 1628 ER_TOO_LONG_TABLE_COMMENT occurs when a CREATE or ALTER TABLE statement sets a comment longer than the 2048-byte limit. Reduce the COMMENT text or split it into external documentation to resolve the issue quickly.</p>
Comment for table '%s' is too long (max = %lu)
MySQL raises error 1628 when the comment defined in a CREATE TABLE or ALTER TABLE statement is larger than the server’s hard limit of 2048 bytes. The operation is aborted and no structural change is applied.
Because comments are stored in the data dictionary, exceeding the limit could impact metadata size and performance. MySQL therefore enforces a strict boundary and returns this runtime error.
The error surfaces immediately after MySQL parses the COMMENT clause and detects that its byte length, after character-set encoding, surpasses the permissible threshold. It affects both new table creations and modifications of existing tables.
Developers usually encounter it during schema migrations, automated deployments, or when copying lengthy documentation text into the COMMENT field.
Unresolved DDL failures halt release pipelines and leave databases in inconsistent states. Trimming comment text restores deploy confidence, enables successful migrations, and prevents downtime in production environments.
Shortening comments or moving extensive documentation to external tools avoids repeated build failures and keeps metadata lean.
Developers sometimes paste full design specs or JSON samples into the COMMENT clause, easily passing 2048 bytes.
ORMs or migration tools may generate verbose comments including column lists, version notes, or audit info.
Storing the same description in multiple languages doubles or triples byte size, quickly breaching the limit.
UTF-8 characters outside ASCII can consume up to 4 bytes each, shrinking the practical character count allowed.
Raised when total row length exceeds the InnoDB page size limit.
Occurs when inserting a value exceeding column length restrictions.
Indicates insufficient privileges to create or modify objects in a database.
A generic DDL failure that may wrap ER_TOO_LONG_TABLE_COMMENT inside its message stack.
MySQL allows up to 2048 bytes, not characters. UTF-8 multi-byte characters reduce the maximum visible length.
No. The boundary is hard-coded in MySQL. Only some MariaDB builds let you recompile to raise it.
Yes, each column COMMENT is also capped at 1024 bytes. Plan documentation accordingly.
Galaxy’s SQL editor highlights comment length in real time and flags queries that exceed 2048 bytes before execution, keeping pipelines green.
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