MySQL 1204: Cannot update entry.

What is MySQL 1204: Cannot update entry.

Check the server's disk space:

df -h

Check the MySQL error log for more details:

grep '1204' /var/log/mysql/error.log

Verify the table's storage engine, focusing on InnoDB status:

SHOW TABLE STATUS LIKE 'yourtablename';

For InnoDB, check if you've hit the `innodbdatafile_path` limit:

SHOW VARIABLES LIKE 'innodbdatafile_path';

Inspect the database and table sizes:

SELECT tableschema AS `Database`, tablename AS `Table`, round(((datalength + indexlength) / 1024 / 1024), 2) `Size in MB` FROM informationschema.TABLES ORDER BY (datalength + index_length) DESC;

If using InnoDB, check the InnoDB storage usage and limits:

SELECT variablename, variablevalue FROM informationschema.globalstatus WHERE variablename IN ('Innodbdatawritten', 'Innodbdata_read');

Increase the database/table size limit if the error is due to a size limit being reached, for instance, by adjusting the `innodbdatafile_path` for InnoDB:

SET GLOBAL innodbdatafile_path = 'ibdata1:12M:autoextend';Note: Adjust the size (`12M`) according to your requirements.

Finally, if applicable, consider purging unnecessary data or archiving old data to free up space.