The problem is not that the column is not created, but that it is not detected as *common* column, and therefore not included in the chunk copy SELECT. Run with PTDEBUG=1 and look for the common columns line.
The problem is not that the column is not created, but that it is not detected as *common* column, and therefore not included in the chunk copy SELECT.
Run with PTDEBUG=1 and look for the common columns line.