Make checkpoint files read/write operations faster

[bersler]

Is your feature request related to a problem? Please describe.
When the schema is very big, the checkpoint file with schema might reach big values. Writing and loading JSON files might be slow.

Describe the solution you'd like
Increase speed of reading and writing JSON files or use a different faster format.

Describe alternatives you've considered
If the checkpoint file is very big, the operation of writing it can be made faster by increasing the interval when the 'interval-mb' and 'interval-s' values. This would force the checkpoint files creation to be done less often.
There is currently no workaround to make faster startup, where the checkpoint file is too big.

Additional context
A different format might be considered to be used.