How can I enable support for pages with more than 16MB of content?

1 Error message for larger pages

The full source of a published page is written into the column source of table publish. Be default this column has a maximum size of 16MB. If pages have published content of more the 16MB, the publish process will fail with an error like Caused by: com.mysql.jdbc.MysqlDataTruncation: Data truncation: Data too long for column 'source'

2 Raising the limit

To raise the limit to 4GB, the following SQL Statement must be used:

ALTER TABLE publish MODIFY column source LONGTEXT;

Depending on the database size, configuration settings and the overall system performance, this change might take some time to complete (up to several hours). During this time, the system will not be fully usable. It is also strongly recommended to make a backup before altering the table.