Hi Srini
There is no technical restriction on number of CVCs to be added into realignment table.
But it´s good to realignment in small chucks because of run times. All the CVCs get locked during this time so it you have big number of CVCs then job could run for longer time and lock the CVCs are longer time.
Make sure you remove Activate Application Log flag to improve your run time.
I hope this information will help you.
Thanks
Amol