I have a big table with BLOB fields that contain many NULL values. I enabled Multiple Tablespaces and got a separate ibd file for each table. The physical size of this table is much more than the size I calculate myself, so my conclusion is that it should be possible to shrink this ibd file, but I am still not able to do this, even after reloading a dump file. I verified the dump file really contains SQL statements that inserts NULL values. Any tips to shrink physical size of this table? Or is this impossible because MySQL allocates a fixed size for blobs?