<p>The server cannot write a failed row record to the internal exceptions table, halting the original statement.</p>
<p>MySQL Error 1627 ER_EXCEPTIONS_WRITE_ERROR appears when the server fails to write to its exceptions table, often due to disk, privilege, or corruption issues. Free space, repair the table, or adjust permissions to resolve.</p>
ER_EXCEPTIONS_WRITE_ERROR
MySQL raises error 1627 with the message "Write to exceptions table failed" when it cannot insert a row into the internal exceptions table that stores details about constraint violations.
The server stops the original INSERT, UPDATE, LOAD DATA, or FOREIGN KEY check and returns SQLSTATE HY000, preventing silent data loss.
Most cases stem from insufficient disk space or file system quotas that block writes to the data directory.
Other triggers include missing or corrupted exceptions tables, read-only file systems, and inadequate MySQL privileges for the mysql schema.
First, confirm there is free disk capacity and no OS quota limits. Next, validate that the mysql.exc or related exceptions table exists and is not corrupted with CHECK TABLE or mysqlcheck.
If corruption is found, repair or recreate the table. Finally, verify that the MySQL process owner has write permissions on the data directory and that the SQL user has INSERT rights on the mysql schema.
High-volume bulk loads often trigger the error when the server exhausts disk space in tmpdir. Clearing tmpdir or moving it to a larger partition resolves the issue.
Upgrades that drop or modify the exceptions table definition can break writes. Running mysql_upgrade or recreating the table from the current MySQL distribution script restores functionality.
Monitor disk usage with automated alerts and allocate headroom for bulk operations. Keep the exceptions table on fast, reliable storage.
Schedule regular CHECK TABLE maintenance and ensure automated backups of the mysql schema so corrupted exceptions metadata can be restored quickly.
When the data directory or tmpdir partition is full, the server cannot append rows to the exceptions table.
Dropped or skipped during an upgrade, the table no longer exists, causing every write attempt to fail.
File system crashes or abrupt power losses can corrupt the exceptions table, blocking further inserts.
The SQL user lacks INSERT or FILE privileges in the mysql schema, preventing the write.
Mount options or OS policies mark the data directory read-only, denying all write operations.
Triggers when creating an index with a name that already exists in the table.
Occurs when an INSERT violates a UNIQUE or PRIMARY KEY constraint.
Raised when a DELETE or UPDATE breaks a foreign key reference.
An underlying file system or storage engine problem stops the requested operation.
No data is written to target tables until the server can log the exception, so transactional integrity remains intact.
The table is core to MySQL's constraint handling and cannot be disabled. Fix the root cause instead.
It is common in MySQL 8.0 and later where advanced constraint checking writes to the exceptions table.
Galaxy's editor surfaces disk alerts and schema validation results inline, letting engineers detect space or schema issues before running heavy DML.
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